Electronic Fuel Injection Service & Diagnostics

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BRIGGS & STRATTON CUSTOMER EDUCATION

ELECTRONIC FUEL INJECTION SERVICE & DIAGNOSTICS

VANGUARD™ 810 EFI BIG BLOCKTM EFI

Contents

Contents Section 1 General Information Oxygen Sensor Caution Information...... 2 P0131/P0132 ...... 19-21 Common Abbreviations...... 3 PE System Lean Wire color Abbreviations ...... 4 P0174...... 22 General Diagnostic Aids...... 5-8 Fuel Injector A and B Mil Blink Diagnostic Trouble Codes ...... 6 P0201/P0202 ...... 23-24 On-Board Diagnostic (OBD) System Check 6 Fuel Pump Relay 490000 Scanning for Diagnostic Trouble Codes ... 6-8 P0230/P0232 ...... 25-26 Tools Needed...... 9 Fuel Pump Relay 610000 Service Precautions...... 10 P0230/P0232 ...... 27-31 General Circuit testing ...... 11-12 Crank Position Sensor Troubleshooting with a DVOM ...... 12 P0336/P0337 ...... 32-33 Troubleshooting with a Test Light...... 12 Ignition Coil A and B Troubleshooting with a Noid Light...... 12 P0351/P0352 ...... 34-35 Wiring...... 13-14 Idle Air Control Model 490000 Component Locator...... 16 P0505...... 36-37 Model 610000 Component Locator...... 17 System Voltage P0562/P0563 ...... 38-39 Fuel and Air Metering System Section 2 Malfunction Indicator Lamp Fuel Supply Components ...... 2-3 P0650...... 40-41 ECM Modes of Operation ...... 2 Closed Loop Control ...... 2 Section 3b Diagnostic Trouble Codes Fuel Pressure Relief Procedure...... 4 Scan Diagnostics Fuel Rail Assembly...... 5 Oxygen Sensor Heater Fuel Injectors ...... 6 P0031/P0032 ...... 2-4 Diaphragm Lift Pump Model 490000 ...... 7-8 Manifold Absolute Pressure Sensor Electric Lift pump for Model 610000 ...... 9-10 P0107/P0108 ...... 5-7 Fuel Pump Module...... 11 Manifold Air Temperature Sensor Throttle Body Assembly ...... 12 P0112/P0113 ...... 8-10 Fuel Flow diagrams...... 13-14 Engine Head Temperature Sensor P0117/P0118...... 11-13 Section 3 Diagnostic Trouble Codes Throttle Position Sensor 490000 ECM Connector Pin-Out ...... 2-3 P0122/P0123 ...... 14-16 EFI System Diagram Model 490000...... 4-5 Throttle Position Sensor 610000 Model 490000 Engine to Chassis diagrams 6-7 P0122/P0123 ...... 17-19 EFI System Diagram Model 610000...... 8-9 Oxygen Sensor Model 610000 Engine to Chassis diagram 10 P0131/P0132 ...... 20-22 Fuse/Relay box component locations...... 11 PE System Lean Diagnostic Trouble Codes List ...... 12 P0174...... 23 Verifying the ECM is Powering Up...... 13 Fuel Injector A and B P0201/P0202 ...... 24-25 Section 3a Diagnostic Trouble Codes Fuel Pump Relay 490000 Non-Scan Diagnostics P0230/P0232 ...... 26-27 Oxygen Sensor Heater Fuel Pump Relay 610000 P0031/P0032 ...... 2-3 P0230/P0232 ...... 28-30 Manifold Absolute Pressure Sensor Crank Position Sensor P0107/P0108 ...... 4-6 P0336/P0337 ...... 31-32 Manifold Air Temperature Sensor Ignition Coil A and B P0112/P0113 ...... 7-9 P0351/P0352 ...... 33-34 Engine Head Temperature Sensor Idle Air Control P0117/P0118...... 10-12 P0505...... 35-36 Throttle Position Sensor 490000 System Voltage P0122/P0123 ...... 13-15 P0562/P0563 ...... 37-38 Throttle Position Sensor 610000 Malfunction Indicator Lamp P0122/P0123 ...... 16-18 P0650...... 39-40 Contents

Contents Section 4 Symptoms Introduction to Symptoms ...... 2 Engine will NOT Crank...... 3 Engine Cranks But Will NOT Start...... 4-5 Hard Start Symptoms ...... 6-7 Engine Has Low Power Output...... 8-9 Engine Hunting and Surging...... 10-11 Possible Symptoms with ECM Connectors 12-13 General Information Section 1 - 1 Contents

Section 1 General Information Caution Information...... 2 Common Abbreviations...... 3 Wire color Abbreviations ...... 4 General Diagnostic Aids...... 5-8 Mil Blink Diagnostic Trouble Codes ...... 6 On-Board Diagnostic (OBD) System Check 6 Scanning for Diagnostic Trouble Codes ... 6-8 Tools Needed...... 9 Service Precautions...... 10 General Circuit testing ...... 11-12 Troubleshooting with a DVOM ...... 12 Troubleshooting with a Test Light...... 12 Troubleshooting with a Noid Light...... 12 Wiring...... 13-14 Model 490000 Component Locator...... 16 Model 610000 Component Locator...... 17 Section 1 - 2 General Information

•CAUTION

To reduce the chance of personal injury and/or property damage, the following instructions must be carefully observed.

Proper service and repair are important to the safety of the service technician and the safe, reli- able operation of all Electronic Fuel Injection (EFI) equipped engines. If part replacement is necessary, the part must be replaced with one of the same part number or with an equivalent part. Do not use a replacement part of lesser quality.

The service procedures recommended and described in this service manual are effective methods of performing service and repair. Some of these procedures require the use of tools specifi- cally designed for the purpose.

Accordingly, anyone who intends to use a replacement part, service procedure, or tool which is not recommended by the manufacturer, must first determine that neither his safety nor the safe operation of the unit will be jeopardized by the replacement part, service procedure or tool selected.

It is important to note that this manual contains various Cautions and Notices that must be carefully observed in order to reduce the risk of personal injury during service or repair, or the possi- bility that improper service or repair may damage the unit or render it unsafe. It is also important to understand that these “Cautions” and “Notices” are not exhaustive, because it is impossible to warn of all the possible hazardous consequences that might result from failure to follow these instructions.

All information, illustrations and specifications contained in this manual are based on the latest product information available at the time of publication approval. The right is reserved to make changes at any time without notice. General Information Section 1 - 3

Common Abbreviations

BARO - BAROMETRIC PRESSURE IC - IGNITION CONTROL BAT - BATTERY, BATTERY POSITIVE IGN - IGNITION TERMINAL, BATTERY OR SYSTEM INJ - INJECTOR VOLTAGE I/O - INPUT/OUTPUT B+ - BATTERY POSITIVE kPa - KILOPASCAL CAN - CONTROLLER AREA NETWORK KV - KILOVOLTS CKT - CIRCUIT MAP - MANIFOLD ABSOLUTE PRESSURE CONN - CONNECTOR MAT - MANIFOLD AIR TEMPERATURE CYL - CYLINDER MFI - MULTIPORT FUEL INJECTION DEG - DEGREES MIL - MALFUNCTION INDICATOR LAMP DIAG - DIAGNOSTIC MSEC - MILLISECOND DLC - DATA LINK CONNECTOR MPR - MAIN POWER RELAY DTC - DIAGNOSTIC TROUBLE CODE N/C - NORMALLY CLOSED DVOM - DIGITAL VOLT OHMMETER N/O - NORMALLY OPEN ECM - ENGINE CONTROL MODULE OBD - ON-BOARD DIAGNOSTIC EHT - ENGINE HEAD TEMPERATURE OPT - OPTIONAL SENSOR PWM - PULSE WIDTH MODULATION EI - ELECTRONIC IGNITION RAM - RANDOM ACCESS MEMORY EFI - ELECTRONIC FUEL INJECTION REF HI - REFERENCE HIGH EMI - ELECTROMAGNETIC INTER- FERENCE REF LO - REFERENCE LOW ENG - ENGINE ROM - READ ONLY MEMORY EOP - ENGINE OIL PRESSURE SPN - SUSPECT PARAMETER NUMBER EST - ELECTRONIC SPARK TIMING SW - SWITCH E-STOP- EMERGENCY STOP TAC - THROTTLE ACTUATOR CONTROL FMI - FAILURE MODE INDICATOR TACH - TACHOMETER GND - GROUND TERM - TERMINAL GOV - GOVERNOR TP - THROTTLE POSITION GPH - GALLONS PER HOUR TPS - THROTTLE POSITION SENSOR O2 - HEATED OXYGEN SENSOR V - VOLTS HG - INCHES OF MERCURY VAC - VACUUM IAC - IDLE AIR CONTROL WOT - WIDE OPEN THROTTLE Section 1 - 4 General Information

Wire Color Abbreviations

ABBREVIATION MAIN COLOR TRACER COLOR BLK - BLACK – BLK/WHT - BLACK / WHITE BLU - BLUE – BLU/BRN - BLUE / BROWN BLU/YEL - BLUE / YELLOW BRN - BROWN – GRN - GREEN – GRN/WHT - GREEN / WHITE GRY - GREY – GRY/BLK - GREY / BLK LT.BLU - LIGHT BLUE – LT.BLU/BLK - LIGHT BLUE / BLACK LT.BLU/WHT - LIGHT BLUE / WHITE LT.GRN - LIGHT GREEN – ORG - ORANGE – ORG/BLK - ORANGE / BLACK ORG/WHT - ORANGE / WHITE PNK - PINK – PNK/BLK - PINK / BLACK RED - RED – RED/WHT - RED / WHITE TAN - TAN – TAN/BLK - TAN / BLACK VIO - VIOLET – VIO/BLK - VIOLET / BLACK VIO/WHT - VIOLET / WHITE WHT - WHITE – WHT/GRN - WHITE / GRN WHT/RED - WHITE / RED YEL - YELLOW – General Information Section 1 - 5

General Diagnostic Aids

Engine Control Module (ECM) Self- Diag- Reading DTC’s using only the MIL blink nostics code. The Engine Control Module (ECM) performs To activate the MIL blink code follow these a continuous self diagnosis on certain control steps. functions. This diagnostic capability is comple- 1. Verify the battery is above 12v. mented by the diagnostic procedures con- 2. Turn off the key switch for 10 seconds. tained in this manual. The ECM’s language for 3. Turn the key ON then OFF, ON then OFF, communicating the source of a malfunction is Then back to the ON position but do not a system of Diagnostic Trouble Codes (DTC’s). start the engine. Each On then OFF se- When a malfunction is detected by the ECM, a quence must be done with less then 2.5 DTC is set and the Malfunction Indicator Lamp seconds in between. (MIL) is illuminated. 4. If the steps are followed correctly the Malfunction Indicator Lamp (MIL) MIL will begin to blink or flash a series of The Malfunction Indicator Lamp (MIL) is de- times. Each series of flashes represents a signed to alert the operator that a problem number. Count the number of blinks and has occurred and that the equipment should this will give you the Diagnostic Trouble be taken for service as soon as reasonably Code(s) that have been set. The DTC(s) possible. As a bulb and system check, the that are in the ECM’s memory current and light will come “ON” with the key “ON,” engine history will blink. “OFF.” When the engine is started, the light NOTE: It is a good technique to write the num- will turn “OFF.” If the light remains “ON,” the bers down after each series has flashed. self-diagnostic system has detected a prob- 5. The DTC’s are four numbers long. There lem. If the problem goes away, the light will is a 1 second pause in between each MIL go out in most cases after 10 seconds, but a blink series. Four series of flashes will give DTC will remain stored in the ECM. When the you the four digit diagnostic trouble code. light remains “ON” while the engine is running, After the DTC(s) are blinked a two digit 61 or when a malfunction is suspected due to an will blink to indicate the DTC(s) have all operational problem, the “On-Board Diagnostic been shown. (OBD) System Check” must be performed as 6. The code 61 will always be the last code the first step. These checks will expose mal- to blink. If code 61 blinks immediately The functions which may not be detected if other ECM has not set any DTC’s and the EFI diagnostics are performed prematurely. system is operating properly.

Diagnostic Trouble Codes DTC’s Example of how to decipher the MIL blink codes with the end code The Engine Control Module (ECM) monitors O O O O O O O O O O =0 all engine operations against preset calibrated One second pause limits. When a component goes outside of its O O =2 One second pause Diagnostic Trouble calibrated limits the ECM sets a DTC. The Code P0251 DTC will be stored in the ECM and the Mal- O O O O O =5 function Indicator Lamp (MIL) will illuminate. One second pause O =1 If the component goes back into it’s normal operation window the MIL will shut off but the Three second pause DTC will still be stored in the ECM under DTC O O O O O O =6 End Code One second pause 61 history until it is cleared. If the MIL stays il- O =1 luminated it indicates a current malfunction in the EFI system and should be serviced imme- Figure 1-1 MIL blink code example. diately. Section 1 - 6 General Information

Reading Diagnostic Trouble Codes (With out using the Mil blink code) The provision for communicating with the ECM is the Data Link Connector (DLC) refer to figure 1-2. It is part of the engine wiring harness, and is a 6-pin connector, which is electrically Figure 1-2 Data Link Connector (DLC) connected to the ECM. The DTC’s stored in Technician Assistant Diagnostic Software the ECM’s memory can be retrieved through a The ECM can communicate a variety of infor- hand-held diagnostic code reader plugged into mation through the DLC. This data is transmit- the DLC, or a PC based software program de- ted at a high frequency which requires a scan signed to interface with the ECM data stream. tool for interpretation. With an understanding of On-Board Diagnostic (OBD) System Check the data which the Technician Assistant Diag- After the visual/physical inspection, the “On- nostic Software displays, and knowledge of Board Diagnostic (OBD) System Check” is the the circuits involved, the scan tool can be very starting point for all diagnostic procedures. The useful in obtaining information which would be correct procedure to diagnose a problem is to more difficult or impossible to obtain with other follow two basic steps: equipment. The Technician Assistant Diagnos- 1. Are the on-board diagnostics working? This tic Software does not make the use of diag- is determined by performing the “On-Board nostic tables unnecessary, nor do they indicate Diagnostic (OBD) System Check.” This is exactly where the problem is in a particular the starting point for the diagnostic proce- circuit. dures. The OBD system check will lead to Technician Assistant Diagnostic Software a diagnostic table in the Diagnosis section With Intermittents to correct the problem. Intermittents are problems that occur in irregu- 2. Is there a DTC stored? If a DTC is stored, lar intervals. The system may function nor- go directly to that DTC table number in the mally most of the time then occasionally have Diagnosis section. problems that seem to fix themselves. This a Using the Tiny Scan tool to read DTC’s good example of an intermittent problem. Connect the Tiny Scan tool to the Diagnostic The Technician Assistant Diagnostic Software Link Connector (DLC). Once connected turn provides the ability to perform a “wiggle test” the ignition “ON” Engine “OFF.” Once the igni- on wiring harnesses or components with the tion is on the Tiny Scan will read all diagnostic engine not running, while observing the dis- trouble codes (DTC’s.) If for some reason the play. Tiny Scan cannot connect to the ECM to read The Technician Assistant Diagnostic Software the DTC’s it will display no-C which means no can be plugged in and observed while operat- communication. ing under the condition when the MIL turns After the DTC’s have been read, the unit will “ON” or the engine operation is poor. If the show how many DTC’s were read. For exam- problem seems to be related to certain param- ple dc-4 means that 4 DTC’s were read. Press- eters that can be checked on the Technician ing the select button will cycle and show each Assistant Diagnostic Software, they should be DTC. After the last DTC is read it will take you checked during operation with engine running. to the cleared code screen, hold the button If there does not seem to be any correlation until the screen says hold and continue to hold between the problem and any specific circuit, it down until it changes to clr (clear). Press- the Technician Assistant Diagnostic Software ing the button again will rescan for persistent can be checked on each position, watching for DTC’s. It is helpful to write down each DTC a period of time to see if there is any change as it is shown to help with further diagnostics in the readings that indicates an intermittent when they are needed. operation. General Information Section 1 - 7

The Technician Assistant Diagnostic Software good diagnostic aid. is also an easy way to compare the operating 1. Connect your code reader, or PC to the 6 parameters of a poorly operating engine with pin diagnostic link connector (DLC) located those of a known good one. For example, a on the wiring harness. You will need to sensor may shift in value but not set a DTC. remove the cap from this connector to ac- Comparing the sensor’s readings with those cess the connector. of a known good identical engine may uncover 2. Turn the ignition key to the on position (key the problem. on), Engine off. The Technician Assistant Diagnostic Software 3. Select the “clear codes” or the “clear has the ability to save time in diagnosis and DTC’s” function prevent the replacement of good parts. The 4. Clear DTC’s key to using the Technician Assistant Diag- 5. Turn Ignition OFF (key off) for at least 20 nostic Software successfully for diagnosis lies seconds. in the technician’s ability to understand the 6. Turn ignition ON and reread DTC’s. If system they are trying to diagnose, as well as DTC’s are still present, check “Notice” an understanding of the Technician Assistant below and repeat procedure following from Diagnostic Software operation and limitations. step 2. The technician should read the tool manufac- NOTICE: When clearing DTC’s with the use of turer’s operating manual to become familiar a code reader, the ignition must be cycled to with the tool’s operation. the OFF position or the DTC’s will NOT clear. How Diagnostic Trouble Codes (DTC) Are Non-Scan Diagnosis of operating concerns Set (No DTC’s Set) The ECM is programmed to receive calibrated If Operating concerns still exist after follow- voltage signals from the sensors. The voltage ing the OBD system check and reviewing the signal from the sensor may range from as low Symptoms tables, an out of range sensor may as 0.1 volt to as high as 4.9 volts. The sensor be suspected. Because of the unique design of voltage signal is calibrated for engine appli- the EFI system, the ECM will replace sensed cation. This would be the sensor’s operating values with calibrated default values in the case parameter or “window.” of a sensor or circuit malfunction. By allowing If a sensor is within its operating or acceptable this to occur, limited engine performance is re- parameters, the ECM does not detect a prob- stored until the engine is repaired. A basic un- lem. When a sensor voltage signal falls out of derstanding of sensor operation is necessary to this “window,” the ECM no longer receives a be able to diagnose an out of range sensor. signal voltage within the operating “window.” If the sensor is out of range, but still within the When the ECM does not receive the “window” operating “window” of the ECM, the problem voltage for a calibratable length of time, a DTC may go undetected by the ECM and may result will be stored. The MIL will be illuminated and in an operation concern. a calibrated default value will replace the sen- A good example of this would be if the Engine sor value to restore engine performance. Head Temperature (EHT) Sensor was reading Clearing Diagnostic Trouble Codes incorrectly and indicating to the ECM that En- The following procedure will instruct you on gine Head Temperature was at 20°F, but the the method for clearing codes from the ECM’s actual temperature was at 150°F. This would fault code memory. cause the ECM to deliver more fuel than what Before you clear codes it is advisable to was actually needed by the engine. This would record the codes by writing them on a piece result in an overly rich condition, causing rough of paper or in your service notebook. Since running. This condition would not have caused you may want to remember which codes were a DTC to set, as the ECM interprets this within set at a later time, writing them down will be a the operating “window”. Section 1 - 8 General Information

To identify a sensor that is out of range, you could unplug the sensor electrical connector while the engine is running. After a short period of time, the DTC for that sensor will set, illuminate the MIL, and replace the sensed value with a calibrated default value. If at that point, a noticeable performance variation is observed, the DTC table for that particular sensor should be followed to correct the problem. NOTICE: Be sure to clear each DTC after dis- connecting and reconnecting each sensor. Fail- ure to do so may result in a misdiagnosis of the operation concern. Battery Disconnect Caution •Caution: Before servicing any electrical component, the ignition key must be in the OFF or LOCK position and all electrical loads must be OFF, unless instructed otherwise in the procedures. As a further precaution, you may want to disconnect the battery cables from the battery terminals. This will help ensure that there will not be any accidental short-to-ground connections. Failure to follow these precautions may cause personal injury and/or damage to the equipment or its components. General Information Section 1 - 9

Special Tool and Equipment

Fuel Pressure Gauge Spark Tester Service Tool Part Service Tool Part # 19627 # 19368

Digital Volt Ohmmeter Extech Ma220 Test Light Service Tool Part (Source Locally) #19602

Back Probe Wire Set Diagnostic Cable Service Tool Part # 19628 # 19625

Tiny Scan Noid Light Code reader Service Tool Part Service Tool Part # 19623 # 19626

BIG BLOCK™ Fuel PSI Test Adapter # 19624 Section 1 - 10 General Information

Service Precautions Service Precautions equipment may either give incorrect test The following requirements must be observed results or damage good components. when working on engines. 11. All measurements using a Digital Volt Ohm- 1. Before removing any ECM system compo- meter (DVOM) must use a digital meter nent, disconnect the negative battery cable. with a rating of 10 megohm input imped- 2. Never start the engine without the battery ance. being solidly connected. 12. When a test light is specified, a “low- 3. Never separate the battery from the on- power” test light must be used. Do not use board electrical system while the engine is a high-wattage test light. While a particu- running. lar brand of test light is not suggested, a 4. Never separate the battery feed wire from simple test on any test light will ensure it to the charging system while the engine is be safe for system circuit testing. Connect running. an accurate ammeter (such as the high im- 5. When charging the battery, disconnect it pedance Digital Volt Ohmmeter DVOM) in from the equipment’s electrical system. series with the test light being tested, and 6. Ensure that all cable harnesses are con- power the test light ammeter circuit with the nected solidly and the battery connections battery. are thoroughly clean. 7. Never connect or disconnect the wiring harness at the ECM when the ignition is switched “ON.” 8. Before attempting any electric arc welding on the equipment, disconnect the battery leads and the ECM connectors. 9. When steam cleaning engines, do not direct the nozzle at any ECM system components. If this happens, corrosion of the terminals or damage of components can take place. 10. Use only the test equipment specified in the diagnostic tables, since other test

testlight DC Amps * + Battery -

If the ammeter indicates less than 3/10 amp (.3A) current ﬂow, the test light is safe to use. If the ammeter indicates more than 3/10(.3A) current ﬂow, the test light is not safe to use. Figure 1-3Test Light Amperage Draw Test General Information Section 1 - 11

General Circuit Testing Visual / Physical Inspection oxidized or loose connections. A careful visual and physical inspection must Before making a connector repair, be certain of the be performed as part of any diagnostic proce- type of connector. Some connectors look similar dure. This can often lead to fixing a problem but are serviced differently. without further diagnostics. Inspect all vacuum Probing Electrical Connectors hoses for correct routing, pinches, cracks or disconnects. Be sure to inspect hoses that Back probe are difficult to see. Inspect all the wires in the Back probing connectors if done properly is a engine compartment for proper connections, safe and effective way to check and verify the burned or chafed spots, pinched wires or con- wiring harness. To back probe a terminal, slide tact with sharp edges or hot manifolds. This the metal pin side of the back probe adaptor in visual/physical inspection is very important. It between the wire and the seal on the back side must be done carefully and thoroughly. of the connector. Push the back probe adaptor gently into the connector until it stops. DO NOT Basic Knowledge and Tools Required To use this manual most effectively, a general force the back probe adaptor into the connector understanding of basic electrical circuits and or it may damage the terminal. circuit testing tools is required. You should be Important: familiar with wiring diagrams, the meaning of • Back probe connector terminals only when voltage, ohms, amps and the basic theories of required in diagnostic procedures. electricity. You should also understand what • Back probing can be a source of damage happens if a circuit becomes open, shorted to connector terminals. Use care in order to ground or shorted to voltage. To perform to avoid deforming the terminal, either by system diagnostics, several special tools and forcing the back probe too far into the cavity equipment are required. Please become ac- or by using too large of a back probe. . quainted with the tools and their use before • After back probing any connector, inspect attempting to diagnose the system. Special for terminal damage. If terminal damage is tools that are required for system service are suspected, test for proper terminal contact. illustrated in this section. Do not disconnect the connector and probe the terminals from the harness side (front) of the Wiring Connector Service Most connectors on the engine wiring harness are connector. protected against moisture and dirt which could Notice: Do not insert test equipment probes into create oxidation and deposits on the terminals. the mating side (front) of any connector or fuse This protection is important because of the block terminal. The diameter of the test probes very low voltage and current levels found in the will deform most terminals. A deformed terminal electronic system. The connectors have a lock can cause a poor connection, which can result in which secures the male and female terminals system failures Do not use paper clips or other together. A secondary lock holds the seal and substitutes as they can damage terminals and terminal into the connector. cause incorrect measurements. When diagnosing, open circuits are often difficult Testing for Intermittent and Poor to locate by sight because oxidation or terminal Connections misalignment are hidden by the connectors. Most intermittent conditions are caused by faulty Merely wiggling a connector on a sensor, or in electrical connections or wiring. Inspect for the the wiring harness, may locate the open circuit condition. This should always be considered when an open circuit or failed sensor is indicated. Intermittent problems may also be caused by Section 1 - 12 General Information

General Circuit Testing following items: at the point being tested. • Wiring broken inside the insulation Troubleshooting using a Noid Light • Poor connection between the male and A noid light can simply and quickly test the fuel female terminal at a connection. injector circuit and the Ignition coil circuit for • Poor terminal to wire connection—Some voltage. conditions which fall under this description To properly operate a noid light use the are poor crimps, poor solder joints, crimping following procedure. over the wire insulation rather than the wire 1. Verify the noid light you are using has itself and corrosion in the wire to terminal the correct terminals on it so it doesn’t contact area, etc. misshape the connector terminals it’s being • Wire insulation which is rubbed through, plugged into. this causes an intermittent short as the bare 2. Plug the noid light into the circuit to be area touches other wiring or parts of the tested. engine. 3. Start or turn over the engine. If the noid light Troubleshooting with a Digital Volt blinks there is voltage at the point being Ohmmeter Test Probe Notice tested. A DVOM should be used instead of a test lamp Measuring Voltage in order to test for voltage in high impedance Notice: Refer to Test Probe Notice circuits. While a test lamp shows whether voltage The following procedure measures the voltage at is present, a DVOM indicates how much voltage a selected point in a circuit. is present. 1. Disconnect the electrical harness connector The ohmmeter function on a DVOM shows how for the circuit being tested, if necessary. much resistance exists between 2 points along 2. Enable the circuit and/or system being tested. a circuit. Low resistance in a circuit means good Use the following methods: continuity. • Ignition ON Engine OFF. Important: Disconnect the power feed from the • Ignition ON Engine ON. suspect circuit when measuring resistance with • Turn on the circuit and/or system with a scan a DVOM. This prevents incorrect readings. A tool in Output Controls. DVOM applies such a small voltage to measure • Turn on the switch for the circuit and/or system resistance that the presence of any other voltages being tested. can upset the resistance reading. 3. Select the V (AC) or V (DC) position on the Diodes and solid state components in a circuit can DVOM. cause a DVOM to display a false reading. To find 4. Connect the positive lead of the DVOM to the out if a component is affecting a measurement take point of the circuit to be tested. a reading once, then reverse the leads and take 5. Connect the negative lead of the DVOM to a a second reading. If the readings differ the solid good ground. state component is affecting the measurement. 6. The DVOM displays the voltage measured at Troubleshooting with a Test Light that point. A test lamp can simply and quickly test a low impedance (low resistance) circuit for voltage. To properly operate a test light use the following procedure. 1. Attach 1 lead to ground. 2. Touch the other lead to various points along the circuit where voltage should be present. 3. When the bulb illuminates, there is voltage General Information Section 1 - 13

Introduction to Wiring

Visual / Physical Inspection Diagnosis A careful visual and physical inspection must The diagnostic tables and functional checks in this be performed as part of any diagnostic proce- manual are designed to locate a faulty circuit or dure. This can often lead to fixing a problem component through logic based on the process without further diagnostics. Inspect all the of elimination. The tables are prepared with the wires in the engine compartment for proper requirement that the system functioned correctly connections, burned or chafed spots, pinched at the time of assembly and that there are no wires or contact with sharp edges or hot mani- multiple failures. folds. This visual/physical inspection is very Engine control circuits contain many special design important. It must be done carefully and thor- features not found in standard equipment wiring. oughly. Environmental protection is used extensively Electrostatic Discharge Damage to protect electrical contacts. Proper splicing Electronic components used in control sys- methods must be used when necessary. tems are often designed to carry very low The proper operation of low amperage input/ voltage, and are very susceptible to damage output circuits depend upon good continuity caused by electrostatic discharge. It is pos- between circuit connectors. It is important sible for less than 100 volts of static electricity before component replacement and/or during to cause damage to some electronic compo- normal troubleshooting procedures that a visual nents. By comparison, it takes as much as inspection of any questionable mating connector 4,000 volts for a person to feel the zap of a is performed. Mating surfaces should be properly static discharge. There are several ways a formed, clean and likely to make proper contact. person can become statically charged. The Some typical causes of connector problems are most common methods of charging are by fric- listed below: tion and by induction. An example of charging • Improperly formed contacts and/or connector by friction is a person sliding across a seat, in housing. which a charge of as much as 25,000 volts can • Damaged contacts or housing due to improper build up. Charging by induction occurs when a engagement. person with well insulated shoes stands near a • Corrosion, sealer or other contaminants on highly charged object and momentarily touch- the contact mating surfaces. es ground. Charges of the same polarity are • Incomplete mating of the connector halves drained off, leaving the person highly charged during initial assembly or during subsequent with the opposite polarity. Static charges of troubleshooting procedures. either type can cause damage. Therefore, it is • Tendency for connectors to come apart due important to use care when handling and test- to vibration and/or temperature cycling. ing electronic components. • Terminals not fully seated in the connector Engine Wiring body. When it is necessary to move any of the wir- • Inadequate terminal crimps to the wire. ing, whether to lift wires away from their har- On-Board Wiring Harness Service nesses or move harnesses to reach some Wiring harnesses should be replaced with proper component, take care that all wiring is re- part number harnesses. When wires are spliced placed in its original position and all harnesses into a harness, use the same gauge wire with high are routed correctly. If clips or retainers break, temperature insulation only. replace them. Electrical problems can result With the low current and voltage levels found in from wiring or harnesses becoming loose and the system, it is important that the best possible moving from their original positions, or from bond be made at all wire splices by soldering the being rerouted. Section 1 - 14 General Information splices as shown in Figure 1-4. Use care when probing a connector or replacing a connector terminal. It is possible to short between adjacent terminals. If this happens, certain components can be damaged. Always use jumper 1. Locate damaged wire wires with the corresponding mating terminals 2. Remove insulation as required. between connectors for circuit checking. NEVER probe through connector seals, wire insulation, secondary ignition wires, boots, nipples or covers. Microscopic damage or holes may result in water intrusion, corrosion and/or 3. Splice two wires together using splice clips component failure. and rosin core solder.

4. Cover splice with tape or heat shrink to insulate from other wires. 5. Re twist as before and tape with electrical tape or heat shrink and hold in place. Figure 1-4 Wire Slicing Procedure General Information Section 1 - 15

This page left intentionally blank Section 1 - 16 General Information

Model 490000 (810 Vanguard) EFI component Locator

CKP Located behind the shroud in the circled Ignition Coil A area. Ignition Coil B Located behind the Located behind the shroud in the circled shroud in the circled area. area.

ECM

MAT/MAP

Fuel Injector A Fuel Injector B

EHT

Fuse Relay Block

HO 2

Figure 1-5 Model 490000 Component locator (Some shrouds have been removed for better component visual aid.) General Information Section 1 - 17

Model 610000 (Big Block) component Locator

MAT/MAP Vertical shaft will be mounted as EHT seen in diagram. Located in the circled area on the engine. Horizontal shaft is located behind the intake manifold in the circled area.

Fuse Relay Block

IAC ECM Fuel Injector B Fuel Injector A

TPS

Ignition Coil B Ignition Coil A

CKP

Figure 1-6 Model 610000 Component locator (Some shrouds have been removed for better component visual aid.) Section 1 - 18 General Information

This page left intentionally blank Fuel and Air Metering System Section 2- 1

Contents

Fuel and Air Metering System Section 2 Fuel Supply Components ...... 2-3 ECM Modes of Operation ...... 2 Closed Loop Control ...... 2 Fuel Pressure Relief Procedure...... 4 Fuel Rail Assembly...... 5 Fuel Injectors ...... 6 Diaphragm Lift Pump Model 490000 ...... 7-8 Electric Lift pump for Model 610000 ...... 9-10 Fuel Pump Module...... 11 Throttle Body Assembly ...... 12 Fuel Flow diagrams...... 13-14 Section 2- 2 Fuel and Air Metering System General Description Purpose jector pulses are not delivered if the ECM does The function of the fuel metering system is to not receive reference pulses from the crank deliver the correct amount of fuel to the engine position sensor, which means the engine is not under all operating conditions. Fuel is deliv- running. ered to the engine by individual fuel injectors Closed Loop Fuel Control mounted in the intake manifold near each The ECM monitors the EHT and oxygen sen- cylinder. sor. The ECM needs to monitor the exhaust Modes Of Operation stream to adjust the air/fuel ratio so that the The ECM looks at inputs from several sen- engine will operate at peak efficiency. Mea- sors to determine how much fuel to deliver to suring the amount of oxygen remaining after the engine. The fuel is delivered under one combustion is a means to indicate the air/ of several conditions, called “modes.” All the fuel ratio. A richer mixture will consume more “modes” are controlled by the ECM and are oxygen during combustion than a leaner mix- described below. ture. The oxygen sensor or air/fuel ratio sensor Starting Mode measures the amount of oxygen remaining On the 490000 Model when the ignition switch after the combustion in the exhaust stream. is turned to the crank position, the ECM turns Using this information and information from the fuel pump “ON.” On the 610000 Model the other sensors on the EFI system the ECM when the ignition switch is turned to the crank will control the injection duration to achieve the position, the ECM sends a ground signal to ideal air/fuel ratio. the fuel pump relay. The ground signal powers NOTE: The engine operation often requires up the relay. The fuel pump relay then sends different air/fuel ratios for starting, maximum B+ to the fuel pump(s). The ECM then checks power and maximum fuel economy. the MAP sensor or barometric pressure and Fuel Pump Electrical Circuit model 490000 determines the proper air/fuel ratio for starting. When the ignition switch is turned “ON,” the The ECM controls the amount of fuel delivered ECM turns the fuel pump “ON” for two sec- in the starting mode by changing how long the onds causing the fuel pump to pressurize the injectors are turned “ON” and “OFF.” This is fuel system. done by “pulsing” the injectors for very short When the ignition switch is turned to the crank times. position, the ECM turns the fuel pump “ON” Run Mode causing the fuel pump to run. During the cranking event, once the engine If the ECM does not receive ignition reference passes a 300 RPM threshold, the engine is pulses (engine cranking or running), it shuts said to be in the RUN mode. The ECM will “OFF” the fuel pump, causing the fuel pump to calculate the desired air/fuel ratio based on stop. these ECM inputs: RPM, EHT sensor and Fuel Pump Electrical Circuit model 610000 MAP. Higher engine loads (MAP input) and (Big Block) colder Engine Head Temperatures (EHT input) When the ignition switch is turned “ON,” the require more fuel, or a richer air/fuel ratio. ECM turns the fuel pump relay “ON” for two Acceleration Mode seconds causing the fuel pump to pressurize The ECM looks at rapid changes in TPS (if the fuel system. equipped) and MAP, and provides extra fuel by When the ignition switch is turned to the crank increasing the injector pulse width. position, the ECM turns the fuel pump relay Fuel Cutoff Mode “ON” causing the fuel pump to run. No fuel is delivered by the injector when the If the ECM does not receive ignition reference ignition is “OFF,” to prevent dieseling. Also, in- pulses (engine cranking or running), it shuts Fuel and Air Metering System Section 2- 3

Fuel Metering System Components (If Equipped) pump module that is located on the side of the engine. The fuel pump module (figure 2-8) has an electric pump and a fuel regulator inside it to maintain a constant pressure of 39 psi through the fuel rail to the fuel injectors. On the marine model 610000 the electric lift pump will be located somewhere in the fuel line between the remote fuel tank and the fuel pump module. The electric diaphragm (figure 2-6) pump pulls fuel from the fuel tank through an in-line filter then pushes it through a second in-line filter and supplies the fuel pump mod- Figure 2-1 Mechanical Diaphragm Fuel Pump ule. The fuel pump module (figure 2-8) has an “OFF” the fuel pump relay, causing the fuel internal fuel regulator inside it to maintain a pump to stop. constant fuel pressure to the fuel injectors. Fuel Injectors The injector assembly is a solenoid like operated device, controlled by the ECM, that me- •Caution: To reduce the risk of fire and ters pressurized fuel to a single engine cylin- personal injury, relieve fuel system pres- der. The ECM energizes the injector, which sure before servicing fuel system compo- opens a pintle valve, allowing fuel to flow past nents. the pintle valve, and through a recessed flow After relieving fuel pressure, a small director plate. The director plate has machined amount of fuel may be released when ser- holes that control the fuel flow, generating a vicing fuel lines or connections. To reduce conical spray pattern of finely atomized fuel the chance of personal injury, cover fuel at the injector tip. Fuel can be directed at the line fittings with a shop towel before dis- intake valve, causing it to become further connecting to catch any fuel that may leak atomized and vaporized before entering the out. Place the towel in an approved con- combustion chamber. tainer when disconnection is completed. Fuel Rail Assembly The fuel rails are either a specially formulated ECM Function hard hose or a rubber flexible hose depending The ECM supplies either 5 or 12 volts to power on the application. An O-ring equipped quick- various sensors or switches. This is done disconnect device is located on the fuel mod- through resistances in the ECM which are so ule. To remove the fuel line squeeze the two high in value that a test light may not illumi- tabs together and gently pull back on the fitting nate when connected to the circuit. In some to disconnect it from the fuel fitting. cases, an ordinary voltmeter will not give an Fuel Supply Components (Pump-on engine) accurate reading because its resistance is The fuel supply is stored in the fuel tank. On too low. Therefore, a digital voltmeter Extech the model 490000 (810 Vanguard) a mechani- Ma220 (Part number 19602) should be used. cal diaphragm pump (figure 2-1) is located The ECM controls output circuits such as the on the plastic shroud near cylinder 2. It uses injectors, relays, etc. by controlling the ground crank case pressure to operate a diaphragm or power feed circuit. style pump to pull fuel from the fuel tanks and Throttle Position Sensor (TPS) If equipped through an in line filter. The diaphragm pump The Throttle Position Sensor (TPS) is a poten- then pushes the fuel to the electrical fuel tiometer connected to the throttle shaft on the Section 2- 4 Fuel and Air Metering System throttle body. By monitoring the voltage on the Fuel Pressure Relief Procedure signal line, the ECM calculates throttle position. As the throttle valve angle is changed, the •Caution: TPS signal also changes, at a closed throttle • Make sure you are wearing proper eye position, the output of the TPS is low. As the protection. throttle valve opens, the voltage output in- • Make sure there are no open flame or creases so that at Wide Open Throttle (WOT) potential ignition devices in the area the out put voltage should be above 4 volts. that you are working. (The TPS is not used on all models.) • Collect any fuel in an approved contain- In-Line Fuel Filter. er and dispose of it properly. On the model 490000 (810 Vanguard) the fuel Tool Required: filter is located on the fuel line in between the Fuel Pressure Gauge (Service Tool Part fuel tanks and the mechanical lift pump. #19627) On the marine model 610000 (Big Block) there 1. Disconnect negative battery cable to avoid are two in-line filters. One is located before the possible fuel discharge if an accidental at- electric lift pump and one after the electric lift tempt is made to start the engine. pump. To replace the filters remove both hose 2. Loosen fuel filler cap to relieve any tank clamps one on either end. vapor pressure. 3. Connect the fuel pressure gauge to the fuel pressure test port (Schrader valve.) Wrap a •Caution: The line may be pressur- shop towel around fitting while connecting ized. Cover the line with a shop towel to the gauge to avoid any spillage. eliminate any fuel discharge. Wear safety 4. Install bleed hose to the fuel pressure glasses at all times. gauge then put the other end of the hose Always replace with a new fuel filter. Most into an approved container and open valve filters will have a direction arrow on the filter. to bleed system pressure. Fuel connections Make sure it is pointing towards the fuel line are now safe for servicing. going to the engine. 5. Drain any fuel remaining in the gauge into Fuel Control On-Board Service an approved container. • The following is general information required when working on the fuel system. • Always keep a dry chemical fire extinguish- er near the work area. • Always bleed off fuel pressure before servicing any fuel system components. • Do not do any repairs on the fuel system until you have read the instructions and checked the figures relating to the repair. • Observe all notices and cautions. Fuel and Air Metering System Section 2- 5

Fuel Rail Assembly 1. Remove the negative battery cable. The fuel rails should be removed as an assem- 2. Remove the air box. bly with the injectors attached. 3. Remove the plastic upper engine shroud. Notice: 4. Disconnect the fuel pump(s) and fuel injec- • Use care in removing the fuel rail assembly tor electrical connectors. to prevent damage to the injector electrical 5. Remove the band clamps and the fuel connector terminals and the injector spray injector caps that attach the fuel rail to the tips. intake manifold and fuel injectors. • Prevent dirt and other contaminants from 6. Remove the fuel injectors and the fuel rail entering open lines and passages. Fittings together. should be capped and holes plugged dur- 7. Squeeze the two tabs together on the quick ing servicing. disconnect fitting and pull away from the Clean pump. • Before removal, the fuel rail assembly may Install or Connect be cleaned with a spray type engine clean- Note: When replacing the fuel rail the entire er, following package instructions. Do Not assembly should be replaced. soak fuel rails in liquid cleaning solvent. 1. Push the quick disconnect fitting back on the fuel pump module. Push firmly until you feel it fully seat. Give the connector a gen- •Caution: Safety glasses must be worn tle tug to insure that it is properly seated. when using compressed air as flying dirt 2. Install Fuel injectors and the fuel rail to- particles may cause eye injury. gether. 3. Connect the fuel pump(s) and fuel injector • Where injectors fit into intake manifold, use electrical connectors. low pressure compressed air to remove 4. Install the plastic upper engine shroud. any debris from around injectors before 5. Install the air box. removing. 6. Hook up the negative battery terminal. Remove or Disconnect Inspect •Caution: To reduce the risk of fire and Turn ignition switch to the “ON” position for 2 Personal injury, relieve the fuel system seconds, then turn to the “OFF” position for 10 pressure before servicing the fuel system seconds. Turn the ignition switch back to the components. “ON” position and check for fuel leaks.

Fuel rail quick disconnect Fuel injector Fuel injector cap Band clamps cap

Figure 2-2 Fuel Rail assembly Section 2- 6 Fuel and Air Metering System

Fuel Injectors Notice: Use care in removing injectors to prevent damage to the injector electrical connector pins or the injector spray tips. The fuel injector is serviced as a complete assembly only. Since it is an electrical component, Do Not immerse it in any cleaner.

•Caution: To reduce the risk of fire and personal injury, relieve fuel system pressure before servicing fuel system components. After relieving fuel pressure, a small amount of fuel may be released when ser- Figure 2-3 Fuel Injector side and top views. vicing fuel lines or connections. To reduce the chance of personal injury, cover fuel burrs or corrosion. Replace injector if dam- line fittings with a shop towel before dis- aged. Clean with spray cleaner and wipe connecting to catch any fuel that may leak groove clean with lint free cloth. out. Place the towel in an approved con- • Do Not use abrasive materials or wire brush tainer when disconnection is completed. on injectors. They are plated with an anti-cor- rosive material. Remove or Disconnect Important 1. Remove the negative battery cable. • When ordering individual replacement fuel 2. Relieve the fuel pressure. injectors, be sure to order the identical part • Refer to the “Fuel Pressure Relief Proce- number that is inscribed on the old injector. dure.” Assemble 3. Remove the fuel rail assembly following 1. Lubricate new injector O-ring seals with the procedures outlined in this section. clean engine oil and install on injector. Disassemble 2. EFI fuel injector assembly into fuel rail 1. The injector will pull right out of the fuel rail. injector socket with electrical connector fac- 2. Remove the bolt on each fuel injector cap ing outward. that secures the fuel rail to the intake mani- Install or Connect fold and fuel injector. 1. Install the fuel rail assembly following pro- 3. Remove the injector O-ring seals from both cedures outlined in this section. ends of the injector and discard. 2. Connect the negative battery cable. Clean and Inspect Inspect Injector bores in fuel rail and intake manifold • Turn ignition switch to the “ON” position for 2 for nicks, burrs or corrosion damage. If severe, seconds, then turn to the “OFF” position for 10 replace. Clean lightly with emery cloth in a seconds. Turn the ignition switch back to the radial motion. “ON” position and check for fuel leaks. Inspect injector O-ring seal grooves for nicks, Fuel and Air Metering System Section 2- 7

Diaphragm Lift Pump for Model 490000 (810 Vanguard) •Caution: • Make sure you are wearing proper eye protection. • Make sure there are no open flame or potential ignition devices in the area where you are working. • Whenever you remove a hose or fitting, make sure to cover the area with a shop Figure 2-4 Mechanical Diaphragm Fuel Pump towel so as to minimize any fuel spray that may occur from residual pressure Fuel Volume Testing The purpose of this test is to verify that the in the line. proper amount of fuel is being delivered to the • Collect any fuel in an approved contain- engine. In order to validate proper delivery er and dispose of it properly. volumes, a volumetric test may be performed. • Be careful not to get any debris in the Since there are two different style pumps used fuel line or fuel pump. on this system, there is a separate test proce- Remove or Disconnect 1. Remove the negative battery cable. dure for each style pump. 2. Relieve fuel pressure. To test the mechanical diaphragm style “lift” or • Refer to the “Fuel Pressure Relief Proce- feeder pump, use the following procedure to dure” in this section. verify the proper volumetric output. 3. Remove the two hose clamps that attach 1. Carefully observe the safety precautions. the two fuel lines to the pump. 2. Disconnect the negative battery terminal. 4. Remove the 2 screws that attach it to the 3. Disconnect the fuel line on the OUTPUT plastic shroud. side of the pump 5. Gently pull the crankcase hose off. 4. With a volumetric measuring device with marked graduations (graduated cylinder Install or Connect or measuring cup), measure the volume of Note: Briggs & Stratton hose clamps should be replaced with factory components to ensure fuel discharged from the pump. To do this, proper fitment and tensions. re-connect the negative battery cable, start 1. Gently push the crank case hose on. the engine and watch for fuel to discharge 2. Mount the diaphragm pump using the two from the now disconnected hose. As soon screws. The diaphragm lift pump should be as you begin to see fuel flow, start a stop- installed in the same position as seen in watch and continue to run for 30 seconds figure 2-4 with the vent port and fuel inlet at 2200 RPM. After 30 seconds, turn off the port pointing down. engine. Refer to the specification chart for 3. Slide the inlet and outlet hose back on and the approximate volume of fuel discharged. clamp them down securely using hose Fuel pumping for 30 seconds clamps. 237 ml 4. Slide the crank case vent hose back onto 0.5 pt the pump. Fuel Amount 5. Connect the negative battery terminal. 0.25 qt Inspect 1.0 cup Start or crank over the engine for 15 to 20 seconds. Check fuel line connections for leaks. Section 2- 8 Fuel and Air Metering System

Note: • The engine will run for a period of longer Engine cranking for 10 seconds than the 30 second interval using fuel 65 ml trapped in the electric pump reservoir. 0.13 pt Fuel Amount • Volumetric measurements are only approxi- 0.06 qt mate. If you are within 10% of the specified 0.27 cup measurement, the pump is likely functioning properly. • If you are measuring the fuel with a measuring device that is placed BELOW the fuel pump. The pump will gravity feed and give you a false reading. Engine Cranks but will not start If the engine cranks but will not start you may choose to perform a volumetric measurement test. Disconnect the output side of the fuel pump. Use a measuring device to measure the amount of fuel. Turn the engine over using the starter for 10 seconds. Compare your results to the chart below. Actual amounts will vary slightly.

Selection valve Fuel Fuel Tank Tank

Inline fuel Filter Measuring Device To Crankcase Vacuum

Figure 2-5 How to measure the flow rate of the diaphragm fuel pump. Fuel and Air Metering System Section 2- 9

Lift Pump For Model 610000 (Big Block) 1. Connect the inlet and outlet hoses and fasten them securely with hose clamps •Caution: 2. Fasten the pump using 2 screws. • Make sure you are wearing proper eye 3. Connect the fuel pump electrical connector protection. to the wiring harness. • Make sure there are no open flame or 4. Connect the negative battery terminal. potential ignition devices in the area Inspect where you are working. Turn ignition switch to the “ON” position for 2 • Whenever you remove a hose or fitting, seconds, then turn to the “OFF” position for 10 make sure to cover the area with a shop seconds. Turn the ignition switch back to the towel so as to minimize any fuel spray “ON” position and check for fuel leaks. that may occur from residual pressure Testing in the line. The purpose of this test is to verify that the • Be careful not to get any debris in the proper amount of fuel is being delivered to the fuel line or fuel pump. engine. In order to validate proper delivery Remove or Disconnect volumes, a volumetric test may be performed. 1. Remove the negative battery cable. Since there are two different style pumps used 2. Disconnect the fuel pump from the wiring on this system, there is a separate test proce- harness dure for each style pump. 3. Relieve fuel pressure. To test the diaphragm style “lift” or electrical • Refer to the “Fuel Pressure Relief Proce- feeder pump, use the following procedure to dure”, in this section. verify the proper volumetric output. 4. Remove the screws that mount the lift 1. Carefully observe the safety precautions. pump. 2. Disconnect the negative battery terminal. 5. Remove both hose clamps that attach the 3. Disconnect the fuel line on the OUTPUT fuel line to the pump. side of the pump Install or Connect 4. With a volumetric measuring device with Note: Briggs & Stratton hose clamps should marked graduations (graduated cylinder be replaced with factory components to ensure or measuring cup), measure the volume proper fitment and tensions. of fuel discharged from the pump. To do this, re-connect the negative battery cable. NOTICE: The fuel pump will prime for 2 seconds when the ignition is keyed on. Do not count that fuel in the measured amount. Start the engine and watch for fuel to discharge from the now disconnected hose. • If the engine will not run, hook a fused jumper wire to the Deutch connector on the lift fuel pump. Hook the other side of the fused jumper wire to 12v B+. 5. As soon as you begin to see fuel flow, start a stopwatch and continue to run for 30 seconds. After 30 seconds, turn off the engine. Refer to the specification chart for the approximate volume of fuel discharged. Figure 2-6 Model 610000 Fuel Lift Pump Section 2- 10 Fuel and Air Metering System

Note: • The engine will run for a period of longer Fuel pumping for 30 seconds than the 30 second interval using fuel 478 ml trapped in the electric pump reservoir. 1.0 pt • Volumetric measurements are only approxi- Fuel Amount 0.5 qt mate. If you are within 10% of the specified measurement, the pump is likely function- 2.0 cup ing properly. • If you are measuring the fuel with a measuring device that is placed BELOW the fuel pump. The pump will gravity feed and give you a false reading. Fuel Tank

Inline fuel Filter

Electric Lift Pump

Measuring Device

Figure 2-7 How to measure the flow rate of the electric lift fuel pump. Fuel and Air Metering System Section 2- 11

Fuel Pump Module For Models 490000 and 610000 •Caution: • Make sure you are wearing proper eye protection. • Make sure there are no open flame or potential ignition devices in the area where you are working. • Whenever you remove a hose or fitting, make sure to cover the area with a shop towel so as to minimize any fuel spray that may occur from residual pressure in the line. • Collect any fuel in an approved container and dispose of it properly. • Be careful not to get any debris in the fuel line or fuel pump. • The electric lift pump is an electrical Figure 2-8 Fuel Pump Module component, Do Not immerse it in any 3. Relieve any residual fuel rail pressure. cleaners. 4. Screw the fuel pressure gauge onto the Remove or Disconnect fuel test port (Schrader valve.) 1. Remove the negative battery cable. • Wrap a shop towel around the fitting as 2. Disconnect the fuel pump module from the you’re screwing it onto the test port to catch wiring harness. any fuel that may leak out. 3. Relieve fuel pressure. 5. Once the fitting is hand tightened “start the • Refer to the “Fuel Pressure Relief Proce- engine.” dure.” The fuel pressure gauge should hold a steady 4. Remove the fuel supply hose. fuel pressure between 35 PSI and 43 PSI. This 5. Remove the fuel rail assembly following the verifies the fuel pump module is working prop- procedures outlined in this section. erly. 6. Remove the mounting bolts Install or Connect 1. Mount the pump using 3 bolts. 2. Mount the fuel rail. 3. Hook up the fuel supply line. 4. Hook the wiring harness into the fuel pump module. 5. Connect the negative battery terminal. Inspect Turn ignition switch to the “ON” position for 2 seconds, then turn to the “OFF” position for 10 seconds. Turn the ignition switch back to the “ON” position and check for fuel leaks. Pressure Testing Procedure 1. Carefully observe the safety precautions 2. Ignition “OFF.” Section 2- 12 Fuel and Air Metering System

Throttle Body Assembly • Discard gasket. The throttle body assembly repair procedures Notice: Use care in cleaning old gasket ma- cover component replacement with the unit on terial from machined aluminum surfaces as the equipment. However, throttle body replace- sharp tools may damage sealing surfaces. ment requires that it be removed from the Install or Connect engine. 1. Install the throttle body assembly with new Clean flange gasket. Important 2. Install the throttle body attaching bolts. • To clean the throttle body following disas- 3. Connect the throttle cable.. sembly, use a spray type cleaner that will 4. Connect the vacuum lines. not damage the material or components.. 5. Connect the electrical connector to the Use a shop towel to remove heavy depos- throttle position sensor and the idle air con- its. trol valve if equipped.. • An approved immersion cleaner may be 6. Install the engines upper shroud. used on disassembled metal parts ONLY. 7. Install the air filter. • When cleaning a throttle body, extreme 8. Reconnect the negative battery cable. care should be taken not to allow solvents of any kind in or near the throttle position sensor or IAC motor if equipped..

Remove or Disconnect 1. Remove the negative battery cable. 2. Remove the air filter. 3. Remove the electrical connector from the throttle position sensor and the idle air control valve if equipped. 4. Remove the vacuum lines. 5. Remove the upper engine shroud. Figure 2-10 Throttle Body Top view (with IAC) 6. Disconnect the throttle cable. 7. Remove the throttle body attaching bolts. 8. Remove the throttle body assembly and flange gasket.

Figure 2-9 Throttle Body Side view (with IAC) Fuel and Air Metering System Section 2- 13

Fuel Flow Diagram (typical for Lawn and Garden) for Model 490000

Fuel Fuel Tank Tank Selection valve

Inline fuel Fuel Injector Fuel Injector Filter

Fuel Test Port (Schrader Valve) See Image Below For a More Detailed View

Vent Port

To Crankcase Vacuum

Fuel Test Port (Schrader Valve) With the valve cap removed.

Figure 2-11 Model 490000 flow direction chart Section 2- 14 Fuel and Air Metering System

Fuel Flow Diagram (typical for Marine) Model 610000 (Big Block)

Fuel Tank

Fuel Injector Fuel Injector

Inline fuel Filters

Fuel Pump Moduel Electric Lift Vent Port Pump

Figure 2-12 Model 610000 flow direction chart Diagnostic Trouble Codes Section 3- 1

Contents

Section 3 Diagnostic Trouble Codes ECM Connector Pin-Out ...... 2-3 EFI System Diagram Model 490000...... 4-5 Model 490000 Engine to Chassis diagrams 6-7 EFI System Diagram Model 610000...... 8-9 Model 610000 Engine to Chassis diagram 10 Fuse/Relay box component locations...... 11 Diagnostic Trouble Codes List ...... 12 Verifying the ECM is Powering Up...... 13 Section 3- 2 Diagnostic Trouble Codes

J1(Grey) ECM Connector

9 1

18 10

Connector/ Wire Color Function Pin Number J1-1 BLU/BRN IACAHI (Idle Air Control A Hi) If equipped J1-2 - N/A (Not Applicable) J1-3 ORG/BLK MIL (Malfunction Indicator Light) J1-4 - N/A (Not Applicable) J1-5 - N/A (Not Applicable) J1-6 - TACHOMETER J1-7 GRN CANLo (Used only for Development ECM) J1-8 YEL CANHi (Used only for Development ECM) J1-9 BLK GROUND (Power) J1-10 PPL/WHT ESTCOILB (Engine Spark Timing Coil B) J1-11 BLU/GRN IACALO (Idle Air Control A Lo) If equipped J1-12 BLU/GRY IACBHI (Idle Air Control B Hi) If equipped J1-13 BLU/RED IACBLO (Idle Air Control B Lo) If equipped J1-14 ORG/WHT Safety Interrupt J1-15 - N/A (Not Applicable) J1-16 - N/A (Not Applicable) J1-17 RED MPR (Main Power Relay) J1-18 - N/A (Not Applicable) Diagnostic Trouble Codes Section 3- 3

J2(Black) ECM Connector

9 1

18 10

Connector/ Wire Color Function Pin Number J2-1 PPL/BLK ESTCOILA (Engine Spark Timing Coil A) J2-2 BLK GROUND (Power) J2-3 PNK SDATA (Serial Data) J2-4 BLK/WHT Crank VR Hi (23X) J2-5 LT. BLU/BLK INJA (Injector A) J2-6 LT. BLU/WHT INJB (Injector B) (Oxygen Sensor Heater) J2-7 WHT/GRN O2HTR If equipped J2-8 TAN/BLK MAT (Manifold Air Temperature) J2-9 BLU/YEL FPR (Fuel Pump Relay) J2-10 BRN 5VRTN1 (5 Volt Return 1) J2-11 WHT/RED MAP (Manifold Absolute Pressure) J2-12 PNK/BLK TPS (Throttle Position Sensor) If equipped J2-13 GRN/WHT Crank VR Lo (23X) J2-14 TAN EHT (Engine Head Temperature Sensor) J2-15 RED IGN (Ignition) J2-16 RED/WHT 5VREF (5 Volt Reference) (Oxygen Sensor) J2-17 GRY/BLK O2Hi J2-18 RED VBAT (Voltage Battery) Section 3- 4 Diagnostic Trouble Codes

Engine Typical Model 490000 EFI System Diagram Control Module (ECM)

Main Power VBAT Relay VBAT 4 10 J2-18

3 9 BLK GND J1-09 RED MPR PPL 20A fuse RED J1-17 IGN/All Switch MPR 15A fuse RED RED IGN J2-15

IGN

ANALOG INPUTS Throttle 1 BRN 5VREF J2-16 PNK/BLK + - Position 3 TPS J2-12 Battery Sensor 2 RED/WHT 5VRTN1 12V GND J2-10 (POWER ) RED/WHT 2 5VREF J2-16 WHT/RED Manifold 1 MAP J2-11 pressure and 4 BRN 5VRTN1 Temperature J2-10 Sensor 3 TAN/BLK MAT J2-08

1 TAN EHT Engine Head J2-14 Temperature 2 BRN 5VRTN1 J2-10

RED MPR A C GRY/BLK Heated 02 HI J2-17 Oxygen D BRN 5VRTN1 Sensor J2-10 B WHT/GRN O2 HTR J2-07

Shielded Twisted Cable Pair 23XVRHI BLK/WHT 2 J2-04 VR Sensor 1 23XVRLO GRN/WHT 23X J2-13 Crank Position (CKP) Sensor TARGET WHEEL DISCRETE INPUTS (The Target Wheel is integrated Saftey Interrupt into the flywheel.) (Safety Circuit Input) ORG/WHT J1-14 Diagnostic Trouble Codes Section 3- 5

Engine Control Typical Model 490000 EFI System Diagram Module (ECM) MPR

YEL COILB(CYL#2) VIO/WHT J1-10

COILA(CYL#1) VIO/BLK Ignition Coil Ignition Coil J2-01

Spark Plugs 1 2 Injector 1 Injector 2

INJA (CYL#1) LT.BLU/BLK AB B A J2-05

INJB (CYL#2) LT.BLU/WHT J2-06 RED MPR BLU/YEL J2-09 FPR

M Fuel Pump

RED MPR

1.4w lamp or LED with resistor J1-03 MIL ORG/BLK

O IGN

SDATA (KW2000 ) PNK J2-03 F K-

E CANLo GRN J1-07 D CAN Lo CANHi YEL J1-08 C CAN Hi BLK B Power Ground RED VBAT A Battery

GND 6-Pin DIAGNOSTIC (POWER ) CONNECTOR

POWER GND BLK J1-09 POWER GND J2-02 Section 3- 6 Diagnostic Trouble Codes

490000 Engine to Chassis Connector

Engine Connector

1 4

2 5 VIO 3 6 YEL/RED Starter 15A Fuse

ORG/WHT RED ORG/BLK J1 14 J2 15 J1 03

IGN MIL Engine Safety Control Interrupt Module (ECM)

Chassis Connector

1.4W Lamp or LED with resister ORG/BLK Saftey Interrupt 4 1

O (Safety Circuit Input) ORG/WHT 5 2 YEL/RED VIO 6 3

IGN Ignition Switch Starter Diagnostic Trouble Codes Section 3- 7

490000 8 way Engine to Chassis Connector

Engine Connector

Starter 15A Fuse YEL/RED

5 6 7 8 1 2 3 4

ORG/WHT ORG/BLK VIO

J1 14 J1 03 J2 15

MIL IGN Engine Safety Control Interrupt Module (ECM)

Chassis Connector

YEL/RED

Starter 8 7 6 5 Ignition Switch 4 3 2 1 IGN VIO

ORG/WHT

ORG/BLK O Saftey Interrupt 1.4W Lamp or (Safety Circuit Input) LED with resister Section 3- 8 Diagnostic Trouble Codes

Engine Typical Model 610000 EFI System Diagram Control Module (ECM)

Main Power VBAT Relay VBAT 4 10 J2-18 MPR 3 9 BLK GND J1-09 RED MPR VIO 20A fuse RED J1-17 15A fuse IGN RED RED IGN J2-15 IGN/All Switch RED RED Fuel Pump Relay Electric Lift Fuel Pump 2 8 M M RED 7 Pump Module 1 BLU/YEL FPR J2-09 BLK GND BLK J1-09 ANALOG INPUTS RED/WHT BLK GND Throttle 1 5VREF J2-16 (POWER ) PNK/BLK + - Position 3 TPS J2-12 Battery Sensor 2 BRN 5VRTN1 12V GND J2-10 (POWER ) RED/WHT 2 5VREF J2-16 WHT/RED Manifold Air 1 MAP J2-11 Pressure and 4 BRN 5VRTN1 Temperature J2-10 Sensor 3 TAN/BLK MAT J2-08

1 TAN EHT Engine Head J2-14 Temperature Sensor 2 BRN 5VRTN1 J2-10

RED MPR Heated A C WHT/GRN O2 HI J2-17 Oxygen D BRN 5VRTN1 Sensor J2-10 B GRY/BLK O2 HTR J2-07

Shielded Twisted Cable Pair 23XVRHI BLK/WHT 2 J2-04 VR Sensor 1 23XVRLO GRN/WHT 23X J2-13 Crank Position (CKP) Sensor TARGET WHEEL DISCRETE INPUTS Saftey Interrupt (The Target Wheel is integrated (Safety Circuit Input) into the flywheel.) ORG/WHT J1-14 Diagnostic Trouble Codes Section 3- 9

Engine Control Typical Model 610000 EFI System Diagram Module (ECM) MPR

YEL COILB(CYL#2) VIO/WHT J1-10

COILA(CYL#1) VIO/BLK Ignition Coil Ignition Coil J2-01

Spark Plugs 1 2 Injector 1 Injector 2

INJA (CYL#1) LT.BLU/BLK AB B A J2-05

INJB (CYL#2) LT.BLU/WHT J2-06 RED MPR

BLU/BRN J1-01 IACAHI D J1-12 IACBHI BLU/GRY B Idle Air Control J1-11 IACALO BLU/GRN C Valve J1-13 IACBLO BLU/RED A

1.4w lamp or LED with resistor J1-03 MIL ORG/BLK

O IGN

SDATA (KW2000 ) PNK J2-03 F K-

E CANLo GRN J1-07 D CAN Lo CANHi YEL J1-08 C CAN Hi BLK B Power Ground RED VBAT A Battery

GND 6-Pin DIAGNOSTIC (POWER ) CONNECTOR

POWER GND BLK J1-09 POWER GND J2-02 Section 3- 10 Diagnostic Trouble Codes

610000 Marine Engine to Chassis Connectors

Engine Connectors

ORG/BLK RED 2 1 FPR

1 6 YEL/RED ORG/WHT Starter 2 5 VIO BLK 15A Fuse 3 4

RED GND

J1 03 J2 15 J2 02 J1 09 J1 14

MIL IGN GND GND Engine Safety Control Interrupt Module (ECM)

Chassis Connectors

Electric Fuel RED ORG/BLK Lift Pump 1 2 O 1.4W Lamp or LED with resister

Saftey Interrupt (Safety Circuit Input) 6 1 ORG/WHT YEL/RED Ignition 5 2 Starter Switch 4 3 VIO IGN Diagnostic Trouble Codes Section 3- 11

Pictorial view of the Fuse/Relay box and Component locations

Typical Fuse/Relay Box For 490000 and 610000 20a Fuse Battery

6 5 4 3 2 1

12 11 10 9 8 7

15a Fuse Fuel Pump Ignition Relay Main Power Relay

490000 Alternative Fuse/Relay Box 20a Fuse Battery

A B C D

HGFE

15a Fuse Main Power Ignition Relay Section 3- 12 Diagnostic Trouble Codes

Diagnostic Trouble Codes (DTC)

DTC System or Component DTC Description Number

Oxygen Sensor Heater P0031 HO2S Heater Circuit High Voltage If equipped P0032 HO2S Heater Circuit Low Voltage Manifold Absolute P0107 MAP Circuit Low Voltage or Open Pressure sensor (MAP) P0108 MAP Circuit High Voltage Manifold Air Temperature P0112 MAT Circuit Low Voltage Sensor (MAT) P0113 MAT Circuit High Voltage or Open Engine Head Temperature sensor Circuit Low Engine Head P0117 Voltage Temperature Engine Head Temperature sensor Circuit High (EHT) Sensor P0118 Voltage or Open Throttle Position P0122 TPS Low Voltage or Open Sensor (TPS) If equipped P0123 TPS High Voltage O S 1 Circuit Low Voltage Oxygen Sensor P0131 2 If equipped P0132 O2S 1 Circuit High Voltage PE System Lean P0174 Lean Fuel Condition while in Power Enrichment Fuel Injector A P0201 Injector A Fault Fuel Injector B P0202 Injector B Fault Fuel Pump P0230 FPR Coil Circuit Low Voltage or Open Relay (FPR) If equipped P0232 FPR Coil Circuit High Voltage Crankshaft P0336 CKP Sensor Noisy Signal Position Sensor (CKP) P0337 CKP Sensor No Signal Ignition Coil A P0351 Cylinder A Ignition Coil Fault Ignition Coil B P0352 Cylinder B Ignition Coil Fault Idle Control System P0505 Idle Speed Control Error If equipped System P0562 System Voltage Low Voltage P0563 System Voltage High MIL P0650 MIL Circuit Malfunction Safety Interrupt P1500 Safety Interrupt Sensor Malfunction/Triggered Sensor Diagnostic Trouble Codes Section 3- 13

Verifying the ECM is Powering Up (Non-Scan Diagnostics)

Circuit Description to actually remove and clean battery terminals. Every component associated with the EFI en- They may appear to be clean , but corrosion gine management system relies on the ECM. can coat the inner surfaces of the terminals Therefore it is imperative that your diagnostic and cause a poor connection to ground. procedures include verification of power and Note: When the ECM is powered up you may grounds to the ECM. There are 4 terminals by hear the fuel pump module prime for 2 sec- which you can verify ECM operation. They are onds, this is not definitive enough to verify the the battery “feed” terminal, the ignition-on ter- ECM is getting the proper voltage. minal and two ground terminals. Be cautious

Step Action Value(s) Yes No 1. Ignition “Off.” 2. With a DVOM connected to a known good 12.2- 1 ground back probe terminal J2-18 of the Go to Step 2 Go to Step 5 13.5v ECM harness connector. Is the voltage within the specified value? 1. Ignition “ON,” Engine “OFF.” 2. With a DVOM connected to a known good 12.2- 2 ground back probe terminal J2-15 of the Go to Step 3 Go to Step 6 13.5v ECM harness connector. Is the voltage within the specified value? 1. Ignition “Off.” 2. Using a DVOM connected to a known good ground take an Ohm reading by 3 2 Ohms Go to Step 4 Go to Step 7 back probing terminal J2-02. Is the resistance less then the specified value? 1. Ignition “Off.” 2. Using a DVOM connected to a known good ground take an Ohm reading by 4 2 Ohms System OK Go to Step 7 back probing terminal J1-09. Is the resistance less then the specified value? Locate and repair open or short to ground in 5 the Battery (B+) feed circuit. -Verify Repair - Is action complete? Locate and repair open or short to ground in 6 the ignition feed circuit. - Verify Repair - Is action complete? Locate and repair open or short in the ECM 7 ground circuit. - Verify Repair - Is action complete? Section 3- 14 Diagnostic Trouble Codes

This page left intentionally blank Diagnostic Trouble Codes Section 3a- 1

Contents

Section 3a Diagnostic Trouble Codes Non-Scan Diagnostics Oxygen Sensor Heater P0031/P0032 ...... 2-3 Manifold Absolute Pressure Sensor P0107/P0108 ...... 4-6 Manifold Air Temperature Sensor P0112/P0113 ...... 7-9 Engine Head Temperature Sensor P0117/P0118...... 10-12 Throttle Position Sensor 490000 P0122/P0123 ...... 13-15 Throttle Position Sensor 610000 P0122/P0123 ...... 16-18 Oxygen Sensor P0131/P0132 ...... 19-21 PE System Lean P0174...... 22 Fuel Injector A and B P0201/P0202 ...... 23-24 Fuel Pump Relay 490000 P0230/P0232 ...... 25-26 Fuel Pump Relay 610000 P0230/P0232 ...... 27-31 Crank Position Sensor P0336/P0337 ...... 32-33 Ignition Coil A and B P0351/P0352 ...... 34-35 Idle Air Control P0505...... 36-37 System Voltage P0562/P0563 ...... 38-39 Malfunction Indicator Lamp P0650...... 40-41 Section 3a- 2 Diagnostic Trouble Codes

DABC

Heated Oxygen Sensor

VIO WHT GRY BLK Inline A B C D Connector

RED WHT/ GRY/ BRN GRN BLK From MPR (Main Power Relay) J2 07JJ2 17 2 10

Oxygen Oxygen 5 Volt Engine Sensor Sensor Return Control Heater Signal Module Low Control (ECM)

DTC P0031/P0032 Oxygen Sensor Heater if equipped (Non-Scan Diagnostics)

Circuit Description Diagnostic Aids

The Heated Oxygen (HO2) Sensor varies volt- Check for the following conditions: age within a range from about 1.0 volt if the Poor connection in harness. Inspect harness exhaust is rich, down to about 0.1 volt if the connectors for backed out terminals, improper exhaust is lean. mating, broken locks, improperly formed or The sensor behaves like an open circuit and damaged terminals and poor terminal to wire produces no voltage when the exhaust tem- connection. perature is below 360°C (600°F). An open For proper wire and connection repairs, refer oxygen sensor circuit or cold oxygen sensor to Wiring Repair. causes an open loop operation. After repairs, clear DTCs following “Clear The heater in the sensor provides a faster DTCs Procedure.” Failure to do so may result sensor warm-up. This allows the sensor to in DTCs not properly being cleared. become active in a shorter period of time and remain active during a long extended idle. DTC P0031 determines if the heated oxygen sensor has developed an open circuit. With an active DTC P0031 set, the system operates in an Open Loop mode and the Malfunction Indicator Lamp (MIL) is turned on. Diagnostic Trouble Codes Section 3a- 3

DTC P0031/P0032 Oxygen Sensor (HO2) Heater (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Disconnect the HO2 sensor electrical connector. 2. Ignition “ON,” Engine “OFF.” 2 3. With a test light connected to a known - Go to Step 3 Go to Step 6 good ground, back probe terminal A of the harness connector. Does the test light illuminate brightly? Using a DVOM back probe between terminals 12.2- 3 A and B of the HO sensor harness connector. Go to Step 4 Go to Step 7 2 13.5v Is the voltage within the specified value? 1. Ignition “ON,” Engine ”OFF.” 2. Using a DVOM connected to a good 4.20- 4 Go to Step 5 Go to Step 8 ground and terminal J2-17 at the ECM. 4.95v Is the voltage within the specified value? 1. Ignition “ON,” Engine “OFF.” 2. Using a DVOM check the voltage between 4.20- 5 Go to Step 10 Go to Step 9 terminals C and D. 4.95v Is the voltage within the specified value? Locate and repair open or short to ground in

6 the ignition feed circuit for the HO2 heater. - Verify Repair - Is action complete? Locate and repair open in the ground circuit

7 for the HO2 heater. - Verify Repair - Is action complete? Locate and repair open in the HO2 sensor signal circuit. 8 - Verify Repair Go to Step 11 If a problem is found, repair as necessary. Was a problem found?

Locate and repair open in the HO2 sensor ground circuit. 9 - Verify Repair Go to Step 11 If a problem is found, repair as necessary. Was a problem found?

Repair faulty HO2 sensor connections or re-

10 place faulty HO2 sensor. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 11 faulty ECM. - Verify Repair - Is action complete? Section 3a- 4 Diagnostic Trouble Codes

Manifold Air Temperature Absolute Pressure 4 3 2 1 (MAT/MAP) Sensor

3 4 1 2

TAN/BLK BRN WHT/RED RED/WHT

J2 08 J2 10 J2 11 J2 16

MAT 5 Volt MAP 5 Volt Engine Sensor Return Sensor Reference Control Signal Signal Module (ECM)

DTC P0107/P0108 Manifold Absolute Pressure (MAP) (Non-Scan Diagnostics)

Circuit Description The Manifold Absolute Pressure (MAP) sen- manifold pressure is equal to atmospheric sor responds to changes in manifold pressure pressure and the signal voltage will be (vacuum). The ECM receives this information high. This information is used by the ECM as a signal voltage that will vary from about as an indication of barometric pressure and 0.5 volts at idle to 4.5 volts at Wide Open is referred to as BARO. Throttle (WOT). 4. If DTC P0107 is set, check for an open in If the MAP sensor fails, the ECM will substitute ground circuit. a default MAP value. 5. If a MAP sensor circuit failure is pres- The MAP sensor voltage of 5 volts is delivered ent, the Throttle Position sensor (TPS) –if to the MAP sensor through the ECM terminal equipped– value will be used along with the J2-16. The MAP sensor will send a voltage MAP sensor default value. signal back to the ECM on terminal J2-11 ac- 6. If the ground is bad in the ECM or the cording to the manifold pressure value on the ground circuit has a bad connection this terminal. could cause multiple DTC's to be set. Diagnostic Aids After repairs, clear DTC's following Clear Check for the following conditions: DTC's Procedure in the General Information 1. Poor connection at ECM. Inspect harness section. Failure to do so may result in DTC's connectors for backed out terminals, im- not properly being cleared. proper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. 2. Damaged harness. Inspect the wiring harness and connectors for damage. 3. With the ignition ON, engine OFF, the Diagnostic Trouble Codes Section 3a- 5 DTC P0107 Manifold Absolute Pressure (MAP) Sensor- Signal Voltage Low (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition OFF. 2. Disconnect MAP sensor harness connector. 3. Connect a jumper wire from harness termi- 2 nal 1 to harness terminal 2. - Go to Step 4 Go to Step 3 4. Start engine and idle for 2 minutes or until code reader indicates a stored DTC. 5. Ignition “ON,” Engine “OFF.” Is DTC P0108 present? 1. Remove jumper wire from terminals 1 and 2. 3 2. Connect DVOM from harness terminal 2 to 4.0v Go to Step 5 Go to Step 6 harness terminal 4. Is voltage reading above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty MAP sensor. - Verify Repair - Is action complete? Locate and repair open or short to ground in the map sensor signal circuit. If a problem is 5 - Verify Repair Go to Step 7 found, repair as necessary. Was a problem found? Locate and repair open or short to ground in 5v reference circuit. 6 - Verify Repair Go to Step 7 If a problem is found, repair as necessary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Section 3a- 6 Diagnostic Trouble Codes

DTC P0108 Manifold Absolute Pressure (MAP) Sensor- Signal Voltage High (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect the MAP sensor harness connector. 2 3. Start the engine and idle for 2 minutes or - Go to Step 4 Go to Step 3 until a DTC is indicated. 4. Ignition “ON,” Engine “OFF.” Is DTC P0107 present? 1. Disconnect the MAP sensor harness connector. 2. Ignition “ON,” Engine “OFF.” 3 4.0v Go to Step 5 Go to Step 6 3. Connect DVOM from harness terminals 2 and 4 at the sensor connector. Is voltage reading above the specified value? Check for plugged or leaking sensor vacuum fitting. Also locate and repair intermittent faulty 4 - Verify Repair - connections. If OK, replace faulty MAP sensor. Is action complete? Locate and repair short to voltage in the MAP sensor signal circuit. If a problem is found, 5 - Verify Repair Go to Step 7 repair as necessary. Was a problem found? Locate and repair open in the sensor ground circuit. If a problem is found, repair as neces- 6 - Verify Repair Go to Step 7 sary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3a- 7

Manifold Air Temperature Absolute Pressure 4 3 2 1 (MAT/MAP) Sensor

3 4 1 2

TAN/BLK BRN WHT/RED RED/WHT

J2 08 J2 10 J2 11 J2 16

MAT 5 Volt MAP 5 Volt Engine Sensor Return Sensor Reference Control Signal Signal Module (ECM)

DTC P0112/P0113-Manifold Air Temperature (MAT) Sensor (Non-Scan Diagnostics)

Circuit Description The Manifold Air Temperature (MAT) Sensor 3. Inspect the wiring harness for damage. uses a thermistor to control the signal voltage 4. If the harness appears to be OK, observe to the ECM. The ECM applies 5 volts on the the MAT display on the code reader while sensor circuit. When the engine is cold, the moving connectors and wiring harnesses sensor (thermistor) resistance is high. As the related to the MAT. A change in the MAT engine warms up, the sensor resistance be- display will indicate the location of the fault. comes lower. 5. If DTC P0113 is also set, check for an open Diagnostic Aids ground. Check for the following conditions: 6. After repairs, clear DTC’s following Clear- 1. Poor connection at ECM. ing DTC’s Procedure in the General Infor- 2. Inspect the wire harness connectors for mation section. Failure to do so may result backed out terminals, improper mating, bro- in DTC’s not properly being cleared. ken locks, improperly formed or damaged terminals and poor terminal to wire connection. Section 3a- 8 Diagnostic Trouble Codes

DTC P0112 Manifold Air Temperature (MAT) Sensor Circuit - Low Temp Indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect the MAT sensor harness connector. 2 3. Ignition “ON,” Engine “OFF.” 4.0v Go to Step 4 Go to Step 3 4. Connect a DVOM by back probing terminals 3 and 4. Is voltage above the specified value? 1. Ignition “OFF.” 2. Connect a DVOM to terminal 3 of the sen- 3 sor connector and a known good ground. 4.0v Go to Step 6 Go to Step 5 3. Ignition “ON,” Engine “OFF.” Is voltage above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty MAT sensor. - Verify Repair - Is action complete? Locate and repair open in the MAT sensor signal circuit. If a problem is found, repair as 5 - Verify Repair Go to Step 7 necessary. Was a problem found? Locate and repair open in the sensor ground circuit. If a problem is found, repair as neces- 6 - Verify Repair Go to Step 7 sary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3a- 9

DTC P0113 Manifold Air Temperature (MAT) Sensor Circuit - High Temp Indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect the MAT sensor harness connector. 2 3. Ignition “ON,” Engine “OFF.” 4.0v Go to Step 3 Go to Step 4 4. Connect a DVOM by back probing terminals 3 and 4 at the sensor connector. Is the voltage above the specified value? Locate and repair intermittent faulty connec- 3 tions. If OK, replace faulty MAT sensor. - Verify Repair - Is action complete? Locate and repair short to ground in MAT signal circuit. If a problem is found, repair as 4 - Verify Repair Go to Step 5 necessary. Was a problem found? Repair faulty ECM connections or replace 5 faulty ECM. - Verify Repair - Is action complete? Section 3a- 10 Diagnostic Trouble Codes

Engine Head Temperature (EHT) Sensor

2 1

GRY GRY Harness Splice

BRN TAN

J2 10 J2 14 5 Volt EHT Engine Return Sensor Control Signal Module (ECM)

DTC P0117/P0118 Engine Head Temperature (EHT) Sensor (Non-Scan Diagnostics)

Circuit Description The Engine Head Temperature (EHT) Sensor uses a thermistor to control the signal voltage Temperature Temperature Resistance to the ECM. The ECM applies 5 volts on the °C °F Ohms sensor circuit. When the engine is cold, the -10 14 58,506 sensor (thermistor) resistance is high. As the 0 32 33,723 engine warms up, the sensor resistance be- 10 50 20,210 comes lower. 20 68 12,542 Diagnostic Aids 30 86 8,032 Check for the following conditions: 40 104 5,292 1. Poor connection at ECM. 50 122 3,578 2. Inspect the wire harness connectors for 60 140 2,477 backed out terminals, improper mating, bro- 80 176 1,263 ken locks, improperly formed or damaged terminals and poor terminal to wire connec- 90 194 927 tion. 110 230 525 3. After repairs, clear DTC's following Clear- 120 248 403 ing DTC's Procedure in the General Infor- 135 275 278 mation section. Failure to do so may result 145 293 221 in DTC’s not properly being cleared. 155 311 177 4. To verify that the Thermistor is working properly check the approximate resistance value with an ohms tester using the table below as a guide. Connector J2 of the ECM must be disconnected before doing a resistance check. Diagnostic Trouble Codes Section 3a- 11

DTC P0117 Engine Head Temperature (EHT) Sensor Circuit - Low Temp Indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “ON,” Engine “OFF.” 2. Connect the DVOM to terminals J2-10 and 1.5- 2 Go to Step 4 Go to Step 3 J2-14 in the ECM connector. 4.5v Is voltage above the specified value? Connect a DVOM to terminal J2-14 and a 3 known good ground. 4.0v Go to Step 6 Go to Step 5 Is voltage above specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty EHT sensor. - Verify Repair - Is action complete? Locate and repair open in the EHT sensor circuit. If a problem is found, repair as neces- 5 - Verify Repair Go to Step 7 sary. Was a problem found? Locate and repair open ground in the 5v return circuit. If a problem is found, repair as 6 - Verify Repair Go to Step 7 necessary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Section 3a- 12 Diagnostic Trouble Codes

DTC P0118 Engine Head Temperature (EHT) Sensor Circuit - High Temperature Indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “ON,” Engine “OFF.” 2. Connect the DVOM to terminals J2-10 and 1.5- 2 Go to Step 3 Go to Step 4 J2-14 in the ECM connector. 4.5v Is voltage above the specified value? Locate and repair intermittent faulty connec- 3 tions. If OK, replace faulty EHT sensor. - Verify Repair - Is action complete? Locate and repair short to ground in the EHT sensor signal circuit. If a problem is found, 4 - Verify Repair Go to Step 5 repair as necessary. Was a problem found? Repair faulty ECM connections or replace 5 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3a- 13

2 2 1 Throttle 3 Position (TPS) Sensor

RED/WHT BRN PNK/BLK

J2 16 J2 10 J2 12

5 Volt 5 Volt TPS Engine Reference Return Sensor Control Signal Module (ECM)

DTC P0122/P0123 Model 490000 Throttle Position Sensor (TPS) If equipped (Non-Scan Diagnostics) Circuit Description The Throttle Position Sensor (TPS) is a poten- bad connection this could cause multiple tiometer connected to the throttle shaft on the DTC's to be thrown. throttle body. By monitoring the voltage on the After repairs, clear DTC's following the Clear signal line, the ECM calculates throttle posi- DTC's Procedure in the General Information tion. As the throttle valve angle is changed, the section. Failure to do so may result in DTC's TPS signal also changes. At a closed throttle not properly being cleared. position, the output of the TPS is low. As the throttle valve opens, the voltage output in- creases so that at Wide Open Throttle (WOT) the output voltage should be above 4 volts. Diagnostic Aids Check for the following conditions: 1. Poor connection at ECM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. 2. Damaged harness. Inspect the wiring harness and connectors for damage. 3. If the ground is bad in the ECM or has a Section 3a- 14 Diagnostic Trouble Codes

DTC P0122 Model 490000 Throttle Position Sensor (TPS) Circuit - Signal Voltage Low (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect TPS harness connector. 3. Connect a jumper wire from harness terminal 2 to harness terminal 3. 2 - Go to Step 4 Go to Step 3 4. Start engine and idle for 2 minutes or until DTC tool indicates a stored DTC. 5. Ignition “ON,” engine “OFF.” Is DTC PO123 present? 1. Remove jumper wire from terminals 2 and 3. 3 2. Connect DVOM by back probing harness 4.0v Go to Step 5 Go to Step 6 terminals 1 and 2 on the sensor connector. Is voltage reading above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty TPS. - Verify repair - Is action complete? Locate and repair open or short to ground in the TPS signal circuit. If a problem is found, 5 - Verify repair Go to Step 7 repair as necessary. Was a problem found? Locate and repair open or short to ground in 6 the 5v reference circuit. - Verify repair Go to Step 7 Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify repair - Is action complete? Diagnostic Trouble Codes Section 3a- 15

DTC P0123 Model 490000 Throttle Position Sensor (TPS) Circuit - Signal Voltage High (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD 1 - Go to Step 2 tem checked? System Check 1. Ignition “OFF.” 2. Disconnect TPS harness connector. 3. Start engine and idle for 2 minutes or until 2 - Go to Step 4 Go to Step 3 DTC tool indicates a stored DTC. 4. Ignition “ON,” Engine “OFF.” Is DTC PO122 present? Disconnect the TPS harness connector. 5. Ignition “ON,” Engine “OFF.” 3 6. Connect DVOM from harness terminal 1 to 4.0v Go to Step 6 Go to Step 5 harness terminal 2. Is voltage reading above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty TPS. - Verify Repairs - Is action complete? Locate and repair open in the 5v return circuit. 5 If a problem is found, repair as necessary. - Verify Repairs Go to Step 7 Was a problem found? Locate and repair short to voltage in the TPS signal circuit. If a problem is found, repair as 6 - Verify Repairs Go to Step 7 necessary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repairs - Is action complete? Section 3a- 16 Diagnostic Trouble Codes

2 2 1 Throttle 3 Position (TPS) Sensor

BRN RED/WHT PNK/BLK

J2 10 J2 16 J2 12

5 Volt 5 Volt TPS Engine Return Reference Sensor Control Signal Module (ECM)

DTC P0122/P0123 Model 610000 Throttle Position Sensor (TPS) (Non-Scan Diagnostics)

Circuit Description The Throttle Position Sensor (TPS) is a poten- bad connection this could cause multiple tiometer connected to the throttle shaft on the DTC's to be thrown. throttle body. By monitoring the voltage on the After repairs, clear DTC's following the Clear signal line, the ECM calculates throttle posi- DTC's Procedure in the General Information tion. As the throttle valve angle is changed, the section. Failure to do so may result in DTC's TPS signal also changes. At a closed throttle not properly being cleared. position, the output of the TPS is low. As the throttle valve opens, the voltage output in- creases so that at Wide Open Throttle (WOT) the output voltage should be above 4 volts. Diagnostic Aids Check for the following conditions: 1. Poor connection at ECM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. 2. Damaged harness. Inspect the wiring harness and connectors for damage. 3. If the ground is bad in the ECM or has a Diagnostic Trouble Codes Section 3a- 17

DTC P0122 Model 610000 Throttle Position Sensor (TPS) Circuit - Signal Voltage Low (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect TPS harness connector. 3. Connect a jumper wire from harness terminal 1 to harness terminal 3. 2 - Go to Step 4 Go to Step 3 4. Start engine and idle for 2 minutes or until DTC tool indicates a stored DTC. 5. Ignition “ON,” engine “OFF.” Is DTC PO123 present? 1. Remove jumper wire from terminals 1 and 3. 3 2. Connect DVOM by back probing harness 4.0v Go to Step 5 Go to Step 6 terminals 1 and 2 on the sensor connector. Is voltage reading above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty TPS. - Verify repair - Is action complete? Locate and repair open or short to ground in the TPS signal circuit. If a problem is found, 5 - Verify repair Go to Step 7 repair as necessary. Was a problem found? Locate and repair open or short to ground in 6 the 5v reference circuit. - Verify repair Go to Step 7 Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify repair - Is action complete? Section 3a- 18 Diagnostic Trouble Codes

DTC P0123 Model 610000 Throttle Position Sensor (TPS) Circuit - Signal Voltage High (Non-Scan Diagnostics)

DABC

Heated Oxygen Sensor

VIO WHT GRY BLK Inline A B C D Connector

RED WHT/ GRY/ BRN GRN BLK From MPR (Main Power Relay) J2 07JJ2 17 2 10

Oxygen Oxygen 5 Volt Engine Sensor Sensor Return Control Heater Signal Module Low Control (ECM)

DTC P0131/P0132-Oxygen (HO2) Sensor If equipped (Non-Scan Diagnostics) Circuit Description Diagnostic Aids

The Heated Oxygen (HO2) sensor(s) varies Check for the following conditions: voltage within a range from about 1.0 volt if the Poor connection in harness. Inspect harness exhaust is rich, down to about 0.1 volt if the connectors for backed out terminals, improper exhaust is lean. mating, broken locks, improperly formed or The sensor behaves like an open circuit and damaged terminals and poor terminal to wire produces no voltage when the exhaust tem- connection. perature is below 360°C (600°F). An open For proper wire and connection repairs, refer oxygen sensor circuit or cold oxygen sensor to Wiring Repair. After repairs, clear DTC’s causes an Open Loop operation. following “Clear DTC’s Procedure.” Failure to The heater in the sensor provides for a faster do so may result in DTC’s not properly being sensor warm-up. This allows the sensor(s) to cleared. become active in a shorter period of time and remain active during a long extended idle. DTC P0131 determines if the heated oxygen sensor has developed an open circuit. With an active DTC P0131 set, the system operates in an Open Loop mode and the Malfunction Indicator Lamp (MIL) is turned on. Section 3a- 20 Diagnostic Trouble Codes

DTC P0131 Heated Oxygen Sensor Low Voltage- Lean Exhaust indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) sys- Go to OBD 1 - Go to Step 2 tem check performed? System check 1. Run the Engine at normal operating temperature 2. Increase the engine speed to a specified value. 2200 rpm 2 3. Using a DVOM check the voltage be- Go to Step 3 Go to Step 4 tween terminal C and D by back probing 0.10v the sensor connector.

Is the HO2 sensor voltage displayed fixed less than the specified value.

1. Disconnect the HO2 sensor electrical connector. 2. Using a jumper wire, connect the HO 2 Refer to sensors low circuit terminal B to a known 0.15- 3 Diagnostic Go to Step 5 good ground. 0.49v Aids 3. Ignition “ON,” Engine “OFF.” Is the voltage displayed on the DVOM within the specified value? If no additional DTC’s are stored, refer to the Go to Applica- 4 Diagnostic Aids. If any additional DTC’s are - - ble DTC Table stored, refer to those table(s) first.

Locate and repair short to ground in the HO2 sensor signal circuit. 5 - Verify Repair Go to step 6 If a problem is found, repair as necessary. Was a problem found? Repair faulty ECM connections or replace 6 faulty ECM. - Verify repair - Is action complete? Diagnostic Trouble Codes Section 3a- 21

DTC P0132 Heated Oxygen Sensor High Voltage- Rich Exhaust indicated (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Run the engine at normal operating temperature. 2. Increase the engine speed to specified 2200 value. RPM 2 3. Using a DVOM check the voltage between Go to Step 3 Go to Step 5 terminal C and D by back probing the har- 0.90v ness connector. Is the voltage displayed above the specified value? Ignition “ON,” Engine “OFF.” Refer to 3 Is the voltage displayed above the specified 0.90v Go to Step 4 Diagnostic value? Aids

1. Disconnect the HO2 sensor electrical connector. 2. Ignition “ON,” Engine “OFF.” 4 0.90v Go to Step 7 Go to Step 6 3. Connect DVOM to terminals C and D. Is the voltage displayed above the specified value? If any additional DTC’s are stored, refer to Go to 5 those table(s) first. - Applicable - DTC Table

Repair faulty HO2 sensor connections or re- 6 place HO2 sensor. - Verify Repair - Is action complete?

Locate and repair short to voltage on the HO2 sensor signal circuit. If a problem is found, 7 - Verify Repair Go to Step 8 repair as necessary. Was a problem found? Repair faulty ECM connections or replace 8 faulty ECM. - Verify Repair - Is action complete? Section 3a- 22 Diagnostic Trouble Codes

DTC P0174 PE System Lean (Non-Scan Diagnostics)

The Power Enrichment (PE) mode is initi- optimal performance and to provide maximum ated in Higher load running conditions. The power. This also prevents against excessive ECM uses the input from the Map sensor and Exhaust valve and engine temperatures. If the Crank Position Sensor to know when to go into DTC P0174 has been set the Engine is not Power Enrichment (PE). PE fueling provides receiving enough fuel. a performance benefit to enrich the engine for

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check Check the fuel filter and fuel lines for debris and or a restriction. If a problem is found, re- 2 Verify Repair Go To Step 3 pair as necessary. Was a problem found? Check the fuel pressure. If a problem is found, 3 repair as necessary. Verify Repair Go To Step 4 Is the fuel pressure within the specified value? Verify the lift pump is operating properly and that the fuel filter is not clogged or restricted. 4 Verify Repair Go To Step 5 If a problem is found, repair as necessary. Was a problem found? Check for vacuum and exhaust leaks. If a 5 problem is found, repair as necessary. - Verify Repair Go To Step 6 Was a leak found? If any additional DTC’s are stored, refer to Go to 6 those table(s) first. - Applicable Go To Step 7 DTC Table Replace faulty fuel injector(s). 7 - Verify Repair Go To Step 8 Is action complete?

Replace faulty HO2 Sensor. Contact 8 Is action complete? - Verify Repair Engine Manufacturer Diagnostic Trouble Codes Section 3a- 23

From MPR (Main Power Relay)

B A RED RED A A

Fuel Fuel Injector Injector Cylinder #1 Cylinder #2

B B

LT. BLU/BLK LT. BLU/WHT J2 05 J2 06

Injector Injector Engine Driver A Driver B Control Module (ECM)

DTC P0201/P0202 Fuel Injectors A and B (Non-Scan Diagnostics) Circuit Description Diagnostic Aids The fault code will indicate which injector is in Check for the following conditions: fault mode. 1. Poor connection at ECM. The Engine Control Module (ECM) controls 2. Inspect the wire harness connectors for fuel injector drivers that are located inside the backed out terminals, improper mating, ECM. An ignition voltage is supplied to the fuel broken locks, improperly formed or dam- injectors. The ECM controls each fuel injector aged terminals and poor terminal to wire by grounding the control circuit via a solid state connection. device called a driver. If the ECM detects an 3. Inspect the wiring harness for damage. incorrect voltage for the commanded state of 4. Check the fuse block for an open fuse. the driver, a fuel injector control DTC will set. After repairs, clear DTC’s following Clearing When a DTC is set it will only indicate which DTC’s Procedure in the General Information fuel injector(s) has a fault. The technician will section. Failure to do so may result in DTC’s have to diagnose if it is a fault in the ground not properly being cleared. circuit or ignition circuit. Important: The ECM/fuel injector fuse also supplies voltage to the ignition coils. If the fuse is open, inspect all related circuits for a short to ground. NOTE: If an ignition coil fault code is active it will turn off the fuel injector for the same cylinder(s) the ignition coil is related to. Section 3a- 24 Diagnostic Trouble Codes

DTC P0201/ P0202 Fuel Injectors High, Low or Open (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Disconnect the appropriate harness connector for each fuel injector. 2. Ignition ”ON,” Engine “OFF.” 3. Using a test lamp connected to a known 2 - Go to Step 3 Go to Step 6 good ground, back probe terminal A of each fuel injector at the harness connector. Does the test lamp illuminate on both harness connectors? 1. Connect the test lamp to B+, back probe terminal B of each fuel injector at the harness connector. 3 - Go to Step 4 Go to Step 5 2. Attempt to start engine. Does the test lamp blink on both harness connectors? 1. Ignition ”ON,” Engine “OFF.” 2. Connect the test lamp to B+, back probe terminal B of each fuel injector at the har- 4 ness connector. DO NOT attempt to start - Go to Step 7 Go to Step 8 the engine. Does the test lamp remain illuminated at all times on either of the ground circuits? Locate and repair an open or short to voltage 5 in the ground circuit. - Verify Repair Go to Step 9 Was a problem found? Locate and repair an open or short to ground 6 in the ignition (B+) circuit. - Verify Repair - Was a problem found? Locate and repair a short to ground in the 7 ground circuit. - Verify Repair Go to Step 9 Was a problem found? Repair faulty fuel injector connections or re- 8 place faulty fuel injector. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 9 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3a- 25

2 EFI Fuel 1 M Pump Module

2 1 RED BLU/ From MPR YEL (Main Power Relay) J2 09 Fuel Pump Engine Control Control Module (ECM)

DTC P0230/P0232 Fuel Pump Relay (FPR) Model 490000 (Non-Scan Diagnostics) Circuit Description Diagnostic Aids Certain engine models do not use a relay to The following conditions may have caused the operate the fuel pump. On these models the fuel pump fuse to malfunction: Engine Control Module (ECM) controls the fuel 1. The fuse is faulty pump module with an internal switch called a 2. There is an intermittent short in the fuel driver. The primary function of the driver is to pump power feed circuit. supply the ground to the fuel pump module. 3. The fuel pump has an intermittent internal This driver has a fault line which the ECM problem. monitors. 4. Poor connection at ECM. If the fault detection circuit senses a voltage 5. Inspect the wire harness connectors for other than what the ECM expects, the fault line backed out terminals, improper mating, status changes causing the DTC to set. broken locks, improperly formed or damaged terminals and poor terminal to wire Improper fuel system pressure results in one connection. or many of the following symptoms: 6. Inspect the wiring harness and relay for • Cranks but will not run damage. • Cuts out, may feel like an ignition problem 7. Check the fuse block for an open fuse. • Poor fuel economy After repairs, clear DTC’s following Clearing • Loss of power DTC’s Procedure in the General Information • Hesitation section. Failure to do so may result in DTC’s • DTC’s not properly being cleared. Section 3a- 26 Diagnostic Trouble Codes

DTC P0230/P0232 Fuel Pump Relay (FPR) Model 490000 (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition ”ON,” Engine “OFF.” 2. Using a DVOM connected to a known good ground, back probe terminal 2 of the 12.2- 2 Go to Step 3 Go to Step 5 fuel pump module harness connector. 13.5v Is the voltage displayed fixed above the specified value? 1. Using a test light connected to a B+, back probe terminal 1 of the fuel pump module harness connector. 3 - Go to Step 6 Go to Step 4 2. Attempt to start engine. Does the test lamp illuminate brightly while cranking? Locate and repair an open or short to voltage 4 in the fuel pump module ground circuit. - Verify Repair Go to Step 7 Was a problem found? Locate and repair an open or short to ground 5 in the fuel pump module ignition (B+) circuit. - Verify Repair - Was a problem found? Repair faulty fuel pump module connections 6 or replace faulty fuel pump module. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3a- 27

From MPR (Main Power Relay) Fuel Pump Relay RED 2 8 2 1 RED RED 1 7 2 2

EFI Fuel Fuel Lift Pump M Pump Module M (Low Pressure) BLU/YEL (High Pressure) J2 09 1 1 Fuel Pump Engine BLK BLK 20a Fuse Control Control Battery Module (ECM) 6 54321

12 11 10 987

15a Fuse Fuel Pump Ignition Main Power Relay Relay DTC P0230/P0232 Model 610000 Fuel Pump Relay (FPR) (Non-Scan Diagnostics)

Circuit Description Diagnostic Aids When the ignition switch is ON, the ECM ac- The following conditions may have caused the tivates the electric fuel pump module and the fuel pump fuse to malfunction: electric lift pump. The lift pump is a diaphragm 1. The fuse is faulty style pump that transfers fuel from the tank to 2. There is an intermittent short in the fuel the fuel pump module. The fuel pump module pump power feed circuit. and lift pump will remain ON as long as the 3. The fuel pump has an intermittent internal ECM receives reference pulses from the crank problem. sensor. If there are no reference pulses, the 4. Poor connection at ECM. ECM turns the fuel pump relay OFF after about 5. Inspect the wire harness connectors for 2 seconds. This shuts off the fuel pumps. The backed out terminals, improper mating, fuel pump module delivers fuel to the fuel rail broken locks, improperly formed or dam- and injectors. The fuel pump module also has aged terminals and poor terminal to wire an internal fuel pressure regulator, that main- connection. tains a fuel pressure of 39 PSI or 270 KPA. 6. Inspect the wiring harness and relay for Improper fuel system pressure results in one damage. or many of the following symptoms: 7. Check the fuse pump for an open fuse. • Cranks but will not run After repairs, clear DTC’s following Clearing • Cuts out, may feel like an ignition problem DTC’s Procedure in the General Information • Poor fuel economy section. Failure to do so may result in DTC’s • Loss of power not properly being cleared. • Hesitation • DTC’s Section 3a- 28 Diagnostic Trouble Codes

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check Check the fuel pump fuse. 2 - Go to Step 9 Go to Step 3 Is the fuse open? 1. Disconnect the fuel pump relay harness connector. 2. Ignition ”ON,” Engine “OFF.” 3 3. Probe the fuel pump relay battery feed - Go to Step 4 Go to Step 12 circuit at the harness connector with a test lamp connected to ground. Does the test lamp illuminate? Probe the fuel pump relay ground circuit at the harness connector with a test lamp connected to B+. 4 - Go to Step 5 Go to Step 13 Refer to the thumbnail wiring schematic for the proper terminal identification. Does the test lamp illuminate? 1. Probe the fuel pump control circuit at the harness connector with a test lamp connected to ground. Refer to the thumbnail wiring diagram for the proper terminal identification. 5 2. Command the fuel pump on by turning the - Go to Step 6 Go to Step 11 Ignition “ON,” Engine “OFF.” NOTE: When the ignition is turned on and the engine is not running the ECM will only power up the FPR for 2 seconds then shut off. Does the test lamp illuminate? 1. Ignition “ON.” 2. Jumper the fuel pump relay battery feed circuit to the fuel pump load circuit at the 6 - Go to Step 18 Go to Step 7 harness connector using a fused jumper wire. 3. Does the fuel pump operate? 1. Leave the fused jumper wire connected. 2. Disconnect the fuel pump harness connector at the fuel pump. 7 3. Probe the power feed circuit in the fuel - Go to Step 8 Go to Step 14 pump harness connector with a test lamp connected to a known good ground. Does the test lamp illuminate? Diagnostic Trouble Codes Section 3a- 29

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open cont’d (Non-Scan Diagnostics) Step Action Value(s) Yes No 1. Leave the fused jumper wire connected. 2. Connect the test lamp between the battery 8 feed circuit and the ground circuit in the - Go to Step 24 Go to Step 15 fuel pump harness connector. Does the test lamp illuminate? 1. Ignition “OFF.” 2. Remove the fuel pump fuse. 3. Disconnect the fuel pump harness connector at the fuel pump. 9 - Go to Step 16 Go to Step 10 4. Probe the load circuit for the fuel pump relay at the harness connector with a test lamp connected to B+. Does the test lamp illuminate? Probe the battery feed circuit for the fuel pump relay at the harness connector with a test 10 - Go to Step 20 Go to Step 21 lamp connected to B+. Does the test lamp illuminate? 1. Ignition “OFF.” 2. Disconnect the ECM connector J2. 3. Measure the continuity of the fuel pump relay control circuit from the fuel pump relay 11 2 ohms Go to Step 22 Go to Step 17 harness connector to the ECM connector using the DVOM. Does the DVOM display the specified value or lower? Repair the open or grounded battery feed circuit to the relay. Replace the fuel pump fuse 12 - Go to Step 25 - if the fuse is open. Is the action complete? Repair the open fuel pump relay ground cir- 13 cuit. - Go to Step 25 - Is the action complete? Repair the open circuit between the fuel pump 14 relay and the fuel pump. - Go to Step 25 - Is the action complete? Repair the open fuel pump ground circuit. 15 - Go to Step 25 - Is the action complete? Repair the short to ground in the fuel pump relay load circuit between the relay and the 16 - Go to Step 25 - fuel pump. Is the action complete? Section 3a- 30 Diagnostic Trouble Codes

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open cont’d (Non-Scan Diagnostics)

Step Action Value(s) Yes No Repair the fuel pump relay control circuit. 17 - Go to Step 25 - Is the action complete? Inspect for poor connections at the relay har- 18 ness connector. - Go to Step 25 Go to Step 19 Did you find and correct the condition? Replace the relay. Refer to Fuel Pump Relay 19 Replacement. - Go to Step 25 - Is the action complete? Repair the short to ground in the battery feed 20 circuit to the fuel pump relay. - Go to Step 25 - Is the action complete? 1. Ignition “OFF.” 2. Re-install the fuel pump relay. 3. Install a new fuse. 4. Connect the fuel pump harness to the fuel pump. Go to 21 5. Command the fuel pump relay ON by turn- - Go to Step 23 Diagnostic ing the Ignition “ON,” Engine “OFF.” Aids NOTE: When the ignition is turned on and the engine is not running the ECM will only power up the FPR for 2 seconds then shut off. Is the fuel pump fuse open? Repair faulty ECM connections or replace 22 faulty ECM. - Go to Step 25 Go to Step 22 Is action complete? 1. Inspect the fuel pump harness for a short to ground. If you find a short, repair the circuit as 23 - Go to Step 25 - necessary. Did you find and correct the condition? 1. Inspect for poor electrical connections at the fuel pump harness before replacing the 24 fuel pump. - Go to Step 25 Go to Step 24 2. Replace the fuel pump. Is the action complete? 1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC Information option using the code reader. 25 - Go to Step 26 - 2. Attempt to start the engine. Does the engine start and continue to operate? Diagnostic Trouble Codes Section 3a- 31

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open cont’d (Non-Scan Diagnostics)

Step Action Value(s) Yes No 1. Idle the engine until the normal operating temperature is reached. Go to 26 2. Select the Diagnostic Trouble Code (DTC) - Applicable System OK option. DTC table Are any DTCs displayed? Section 3a- 32 Diagnostic Trouble Codes

TARGET WHEEL Crank Position (CKP) Sensor VR Sensor 1 23X Inline 2 1 Connector BLK/ GRN/ WHT WHT

Twisted Cable Pair

BLK/ GRN/ WHT WHT

2 2 13

CKP CKP Engine 23X 23X Control VR HI VR LO Module (ECM)

DTC P0336/P0337 Crankshaft Position (CKP) Sensor (Non-Scan Diagnostics) Modes of Operation Diagnostic Aids The crankshaft position (CKP) sensor works in Check for the following conditions: conjunction with the 23X reluctor target wheel 1. Verify that the Crank Position Sensor is on the flywheel. Each tooth on the reluctor gapped at .30 from the target wheel. wheel is equally spaced with 1 tooth missing 2. Poor connection at ECM. Inspect harness for the reference sync pulse. As the crankshaft connectors for backed out terminals, im- rotates, the reluctor target wheel interrupts a proper mating, broken locks, improperly magnetic field produced by a magnet internal formed or damaged terminals and poor to the sensor. The CKP sensor internal cir- terminal to wire connection. cuitry detects this interruption of the magnetic 3. Damaged harness. Inspect the wiring har- field, and produces an ON/OFF AC voltage of ness for damage. If the ground is bad in the varying frequency. The frequency of the CKP ECM or has a bad connection this could sensor output signal is dependent upon crank- cause multiple DTC’s to be thrown. shaft speed. The ECM uses each CKP output After repairs, clear DTC’s following clear signal to determine crankshaft speed, and DTC’s Procedure in the General Information identify crankshaft position. section. Failure to do so may result in DTC’s There is one normal mode of operation, with not properly being cleared. the spark under control of the ECM. If the CKP signal is lost the engine will not run. The ECM will not be able to determine which stroke the pistons are on. Diagnostic trouble codes are available to accurately diagnose the ignition system with the code reader. Diagnostic Trouble Codes Section 3a- 33

DTC P0336/P0337 Crankshaft Position (CKP) Sensor (Non-Scan Diagnostics)

Step Action Value(s) Yes No Did you perform the “On-Board Diagnostic” Go to 1 (OBD) System Check? - Go to Step 2 OBD System Check 1. Ignition “OFF.” 2. Back probe the ECM connector at terminals J2-04 and J2-13. 3. Using a DVOM set to AC voltage turn over 2 Go to Step 7 Go to Step 3 the engine. 0.95v Does the DVOM indicate that the CKP is giving off an AC voltage above the specified range? 1. Ignition “OFF.” 2. Back probe the CKP sensor connector at terminals 1 and 2. 3. Using a DVOM set to AC voltage turn over 3 Go to Step 4 Go to Step 5 the engine. 0.95v Does the DVOM indicate that the CKP is giving off an AC voltage above the specified range? Locate and repair short or open in the CKP circuit. If a problem is found, repair as neces- 4 - Verify Repair Go to Step 5 sary. Was a problem found? Verify the CKP is clean and mounted cor- 5 rectly. - Verify Repair Go to Step 6 Was a problem found? Repair faulty CKP connections or replace 6 faulty CKP. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Section 3a- 34 Diagnostic Trouble Codes

From MPR (Main Power Relay)

YEL YEL AB Inline Inline B A Connector B A Connector

Ignition Ignition Ignition Coil Coil Ignition Coil Coil Cylinder #1 Cylinder #2

Spark Plugs Spark Plugs

VIO/BLK VIO/WHT

J2 01 J1 10 Ignition Ignition Engine Coil Coil Control Driver A Driver B Module (ECM)

DTC P0351/P0352 Ignition Coil A and B (Non-Scan Diagnostics) Circuit Description Each ignition coil has an ignition (B+ volt- continue to run on one cylinder if no fault is set age) and a ground circuit. The engine control for the opposite cylinder. module (ECM) supplies an ignition control (IC) If there is no spark and a DTC has NOT set circuit and a low reference circuit. Each igni- check the coil wire to the spark plug for good tion coil contains a solid state driver module connectivity. that is located inside the ECM. The ECM will Important: The ECM/ignition coil fuse also command the IC circuit ON, which allows the supplies voltage to the fuel injectors. If the fuse current to flow through the primary coil wind- is open, inspect all related circuits for a short ings for the appropriate time or dwell. When to ground. the ECM commands the IC circuit OFF, this Diagnostic Aids will interrupt current flow through the primary Check for the following conditions: coil windings. The magnetic field created by 1. Poor connection at ECM. the primary coil windings will collapse across 2. Inspect the wire harness connectors for the secondary coil windings, which induces a backed out terminals, improper mating, bro- high voltage across the spark plug electrodes. ken locks, improperly formed or damaged The primary coils are current limited to prevent terminals and poor terminal to wire connec- overloading if the IC circuit is held ON for an tion. extended time. 3. Inspect the wiring harness for damage. The fault code will indicate which coil is in 4. Check the fuse block for an open fuse. fault. After repairs, clear DTC’s following Clearing When an ignition coil fault is set the ECM will DTC’s Procedure in the General Information also shut down the fuel injector for the same section. Failure to do so may result in DTC’s cylinder that the fault is set on. The engine will not properly being cleared. Diagnostic Trouble Codes Section 3a- 35

DTC P0351/P0352 Ignition coil(s) High, Low or Open (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Disconnect the appropriate harness connector for each Ignition coil. 2. Ignition ”ON,” Engine “OFF.” 3. Using a test lamp connected to a known 2 - Go to Step 3 Go to Step 6 good ground, back probe terminal A of each ignition coil harness connector. Does the test lamp illuminate on both harness connectors? 1. Connect the test lamp to B+; back probe terminal B of each ignition coil harness connector. 3 - Go to Step 4 Go to Step 5 2. Attempt to start engine. Does the test lamp blink on both harness connectors? 1. Ignition ”ON,” Engine “OFF.” 2. Connect the test lamp to B+; back probe terminal B of each ignition coil harness 4 connector. DO NOT attempt to start the - Go to Step 7 Go to Step 8 engine. Does the test lamp remain illuminated at all times on either of the ground circuits? Locate and repair an open or short to voltage 5 in the ground circuit. - Verify Repair Go to Step 9 Was a problem found? Locate and repair an open or short to ground 6 in the ignition (B+) circuit. - Verify Repair - Was a problem found? Locate and repair short to ground in the 7 ground circuit. - Verify Repair Go to Step 9 Was a problem found? Repair faulty fuel injector connections or re- 8 place faulty fuel injector. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 9 faulty ECM. - Verify Repair - Is action complete? Section 3a- 36 Diagnostic Trouble Codes

D C B A Idle Air Control (IAC) Valve

A C B D

BLU/RED BLU/GRN BLU/GRY BLU/BRN

J1 13JJ1 11 J1 12 1 01

IAC B IAC A IAC B IAC A Engine Low Low High High Control Control Control Control Control Module (ECM)

DTC P0505 Idle Air Control (IAC) Valve If equipped (Non-Scan Diagnostics)

Circuit Description sult in improper idle control. The ECM controls idle speed to a calibrated 4. An IAC valve which is frozen and will not desired RPM based on sensor inputs and respond to the ECM, a throttle stop screw actual engine RPM. The ECM uses four (4) cir- which has been tampered with, or a dam- cuits to move the Idle Air Control (IAC) valve. aged throttle body or linkage may cause The movement of the IAC valve varies the improper idle. amount of air flow bypassing the throttle plates. The ECM controls idle speed by deter- mining the position of the IAC valve. Diagnostic Aids Check for the following items: 1. Poor connection or damaged harness. Inspect the ECM harness and connectors for improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness. 2. Check for vacuum leaks, disconnected or brittle vacuum hoses, cuts, etc. Examine manifold and throttle body gaskets for proper seal. Check for cracked intake manifold. 3. Check for poor connections, opens or short to grounds in the IAC circuit. This may re- Diagnostic Trouble Codes Section 3a- 37

DTC P0505 Idle Air Control (IAC) Valve Test (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Engine should be at normal operating temperature. 2. Start engine and allow idle to stabilize. 3. Record RPM. 200 2 4. Ignition “OFF” for 10 seconds. Go to Step 3 Go to Step 4 RPM 5. Disconnect IAC harness connector. 6. Restart engine and record RPM. Is RPM higher than the first recorded RPM by more than the specified value? 1. Reinstall IAC harness connector. 2. Idle speed should gradually return within 3 75 RPM of the original recorded RPM - Go to Step 5 Go to Step 4 within 30 seconds. Does RPM return to original recorded RPM? 1. Ignition “OFF” for 10 seconds. 2. Disconnect IAC harness connector. 3. Restart engine. 4 4. Using a test lamp connected to a known - Go to Step 7 Go to Step 8 good ground, back probe each one of the four IAC harness terminals. Does the test lamp blink on all four terminals? 5 IAC circuit is functioning properly. - - - Locate and repair poor connection, open, or short to ground in the IAC circuit that did not Go to OBD 6 blink. If a problem was found, repair as neces- - System Go to Step 8 sary. Check Was a problem found? Check for poor IAC connections or replace the Go to OBD 7 faulty IAC valve. - System - Is action complete? Check Repair faulty ECM connections or replace Go to OBD 8 faulty ECM. - System - Is action complete? Check Section 3a- 38 Diagnostic Trouble Codes

Main Power Relay For Fuse/Relay block 4/C 10/F pictorial refer to section 3-11 3/D 9/E 20a Fuse Battery

6 524 3 1 20 AMP Fuse 789101112

15a Fuse Fuel Pump Ignition Main Power Relay Ignition Switch Relay RED 15 AMP Fuse

REDRED REDBLK + -

Battery J2 15J1 17 J2 18J1 09 12V GND IGN MPR Battery Ground Engine Control Module (ECM)

DTC P0562/P0563 System Voltage (Non-Scan Diagnostics) Circuit Description The EFI system operates with a battery volt- To further diagnose system voltage faults, refer age from 9 to 16 volts. If the system voltage to Briggs & Stratton Intec V-Twin Cylinder OHV drops below 6.2 volts the ECM will reset. The Repair Manual section 7. Malfunction Indicator Light (MIL) will illuminate Diagnostic Aids if the voltage is below 9 volts or above 16 volts Check for the following conditions: for a specified amount of time during normal 1. Poor connection at ECM. Inspect harness operation. connectors for backed out terminals, im- To determine the system voltage to the ECM, a proper mating, broken locks, improperly voltage measurement can be taken at a termi- formed or damaged terminals and poor nal J2-18. If the voltage at terminal J2-18 is not terminal to wire connection. within 0.01 volt of the measurement you get at 2. Damaged harness. Inspect the wiring har- the battery (measuring between the positive(+) ness and connectors for damage. and negative(-) posts of the battery with your After repairs, clear DTC’s following Clear DVOM), determine the fault associated with DTC’s Procedure in the General Information circuit J2-18. section. Failure to do so may result in DTC’s Similarly, you should be able to measure bat- not properly being cleared. tery voltage on terminal J2-15 with the ignition switch in the on position and the engine not running. Refer to the diagram above to locate the two terminals on the ECM that provide battery voltage and ignition-on voltage. Diagnostic Trouble Codes Section 3a- 39

DTC P0562/P0563 System voltage (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Key “OFF” Engine “OFF.” 2. Check the battery for voltage with a 12.2- 2 Go to Step 3 Go to Step 5 DVOM. 13.5v Is the battery within specified value? 1. Ignition “OFF” Engine “OFF.” 2. Check if the ECM has battery voltage at ECM terminal J2-18 with a DVOM con- 3 - Go to Step 4 Go to Step 9 nected to a known good ground. Was the voltage within 0.5 of the battery voltage? 1. Ignition “ON” Engine “OFF.” 2. Check for ignition voltage at ECM terminal J2-15 with a DVOM connected to a known 4 - Go to Step 5 Go to Step 10 good ground. Was the voltage within 0.5v of the battery voltage? Check charging system. Refer to Briggs & Stratton manual for intec V-Twin Cylinder OHV 5 - Go to Step 7 Go to Step 6 Repair Manual section 7 Is the charging system OK? Locate and repair charging system. Refer to Briggs & Stratton manual for intec V- 6 - Verify Repair - Twin Cylinder OHV Repair Manual section 7 Is action complete? Verify good continuity at the battery terminals. 7 - Verify Repair Go to Step 8 Repair if necessary. Replace battery. 8 - Verify Repair - Is action complete? Locate and repair an open or short to ground 9 in the battery feed circuit. - Verify Repair - Is action complete? Locate and repair an open or short to voltage 10 in the ignition feed circuit. - Verify Repair - Is action complete? Section 3a- 40 Diagnostic Trouble Codes

1.4W Lamp or LED with resister O

IGN

ORG/BLK

J1 03 MIL Engine Control Module (ECM)

DTC P0650 Malfunction Indicator Lamp (MIL) Diagnosis (Non-Scan Diagnostics)

Circuit Description The Malfunction Indicator Lamp (MIL) gets proper mating, broken locks, improperly 12v B+ when the ignition is in the on or run formed or damaged terminals and poor position. The ECM sends a ground signal to terminal to wire connection. illuminate the MIL when the ignition is on and 2. Damaged harness. Inspect the wiring har- the engine is NOT running. The ECM will also ness for damage. If the harness appears to send the ground signal to activate the light if be OK, observe the Malfunction indicator one or more of the malfunctions exists under Lamp (MIL) display while moving connec- the conditions listed in the DTC’s table. If the tors and wiring harnesses related to the malfunction clears, the lamp will go out and MIL. A change in the MIL display will indi- the Diagnostic Trouble Code (DTC) will be cate the location of the fault. stored in the ECM. The amount of time after After repairs, clear DTC's following Clear the malfunction occurs before the MIL illumi- DTC's Procedure in the General Information nates is calibratable. (Instantly or up to several section. Failure to do so may result in DTC's minutes). not properly being cleared. Do not clear the DTC’s unless directed by a diagnostic procedure. Clearing the DTC’s may also clear valuable diagnostic information. Diagnostic Aids Check for the following conditions: 1. Poor connection at ECM. Inspect harness connectors for backed out terminals, im- Diagnostic Trouble Codes Section 3a- 41

DTC P0650 Malfunction Indicator Light (MIL) Malfunction (Non-Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 checked? - Go to Step 2 System Check 1. Ignition “OFF.” 2. Using a test light hooked to a known good 2 - Go to Step 3 Go to Step 4 ground probe the Ignition side of the MIL. Does the test lamp Illuminate brightly? 1. Ignition “On,” Engine “OFF.” 2. Using a test light connected to a known good 3 - Go to Step 5 Go to Step 4 ground probe the Ignition side of the MIL. Does the test lamp Illuminate brightly? Locate and repair an open or short to ground in the battery feed circuit. If a problem was found, 4 -Verify repair - repair as necessary Is action complete? 1. Ignition “OFF.” 2. Using a test light connected to B+ probe the 5 - Go to Step 7 Go to Step 6 ground side of the MIL. Does the test lamp Illuminate brightly? 1. Ignition “On,” Engine “OFF.” 2. Using a test light connected to B+ back 6 probe the terminal J1-03 of the ECM connec- - Go to Step 8 Go to Step 9 tor. Does the test lamp Illuminate brightly? Locate and repair poor connection or open in the ground circuit. If a problem was found, repair as 7 - Verify Repair - necessary. Was a problem found? Repair faulty MIL connections or replace faulty 8 MIL. - Verify Repair - Is action complete? Repair faulty ECM connections or replace faulty 9 ECM. - Verify Repair - Is action complete? Section 3a- 42 Diagnostic Trouble Codes

This page left intentionally blank Diagnostic Trouble Codes Section 3b - 1

Contents

Section 3b Diagnostic Trouble Codes Scan Diagnostics Oxygen Sensor Heater P0031/P0032 ...... 2-4 Manifold Absolute Pressure Sensor P0107/P0108 ...... 5-7 Manifold Air Temperature Sensor P0112/P0113 ...... 8-10 Engine Head Temperature Sensor P0117/P0118...... 11-13 Throttle Position Sensor 490000 P0122/P0123 ...... 14-16 Throttle Position Sensor 610000 P0122/P0123 ...... 17-19 Oxygen Sensor P0131/P0132 ...... 20-22 PE System Lean P0174...... 23 Fuel Injector A and B P0201/P0202 ...... 24-25 Fuel Pump Relay 490000 P0230/P0232 ...... 26-27 Fuel Pump Relay 610000 P0230/P0232 ...... 28-30 Crank Position Sensor P0336/P0337 ...... 31-32 Ignition Coil A and B P0351/P0352 ...... 33-34 Idle Air Control P0505...... 35-36 System Voltage P0562/P0563 ...... 37-38 Malfunction Indicator Lamp P0650...... 39-40 Section 3b- 2 Diagnostic Trouble Codes

DABC

Heated Oxygen Sensor

VIO WHT GRY BLK Inline A B C D Connector

RED WHT/ GRY/ BRN GRN BLK From MPR (Main Power Relay) J2 07JJ2 17 2 10

Oxygen Oxygen 5 Volt Engine Sensor Sensor Return Control Heater Signal Module Low Control (ECM)

DTC P0031/P0032 Oxygen Sensor Heater If equipped (Scan Diagnostics)

Circuit Description Diagnostic Aids

The Heated Oxygen (HO2) Sensor varies volt- Check for the following conditions: age within a range from about 1.0 volt if the Poor connection in harness. Inspect harness exhaust is rich, down to about 0.1 volt if the connectors for backed out terminals, improper exhaust is lean. mating, broken locks, improperly formed or The sensor behaves like an open circuit and damaged terminals and poor terminal to wire produces no voltage when the exhaust tem- connection. perature is below 360° C (600°F). An open For proper wire and connection repairs, refer oxygen sensor circuit or cold oxygen sensor to Wiring Repair. causes an open loop operation. After repairs, clear DTC’s following “Clear The heater in the sensor provides a faster DTC’s Procedure.” Failure to do so may result sensor warm-up. This allows the sensor to in DTC’s not properly being cleared. become active in a shorter period of time and remain active during a long extended idle. DTC P0031 determines if the heated oxygen sensor has developed an open circuit. With an active DTC P0031 set, the system operates in an Open Loop mode and the Malfunction Indicator Lamp (MIL) is turned on. Diagnostic Trouble Codes Section 3b - 3

DTC P0031/P0032 Oxygen Sensor (HO2) Heater - Voltage High, Low or Open (Scan Diagnostics) Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check

1. Disconnect the HO2 sensor electrical connector. 2. Using a DVOM connected to a known 12.2- 2 good ground, and terminal J1-17 in the Go to Step 3 Go to Step 8 13.5v ECM harness connector. Does DVOM indicate a voltage within the specified value? Using a DVOM back probe the sensor connector at terminals A and B. 12.2- 3 Go to Step 4 Go to Step 9 Does DVOM indicate a voltage within the 13.5v specified value?

1. Reconnect the HO2 sensor electrical connector. 2. Connect scan tool. 3. Run the engine at a normal operating tem- 2200 4 perature. Go to Step 7 Go to Step 5 RPM 4. Run the engine above the specified value for at least two minutes. Does the scan tool indicate Closed Loop Fuel control? 1. Ignition “OFF.”

2. Disconnect the HO2 sensor electrical connector. 3. Install a jumper between the sensor con- 5 nector terminals C and D. 0.1v Go to Step 12 Go to Step 6 4. Ignition “ON,” Engine “OFF.”

Does the scan tool HO2 sensor voltage display indicate a voltage less than the specified value? 1. Ignition “OFF.” 2. Remove the jumper wire. 3. Ignition “ON,” Engine “OFF.” 4. Using a DVOM back probe sensor connec- 12.2- 6 tor B. Go to Step 10 Go to Step 11 13.5v 5. Then probe B+(battery Positive) with the other lead wire from the DVOM. Does the voltage read within the specified range? Section 3b- 4 Diagnostic Trouble Codes

DTC P0031/P0032 Oxygen Sensor (HO2) Heater - Voltage High, Low or Open cont’d (Scan Diagnostics)

Step Action Value(s) Yes No If any additional DTC’s are stored, refer to Go to 7 those table(s) first. - Applicable - DTC Table Locate and repair open or short to ground in

8 the ignition feed circuit for the HO2 heater. - Verify Repair - Is action complete? Locate and repair open in the ground circuit

9 for the HO2 heater. - Verify Repair - Is action complete?

Locate and repair open in the HO2 sensor signal circuit. If a problem is found, repair as 10 - Verify Repair Go to Step 13 necessary. Was a problem found?

Locate and repair open in the HO2 sensor ground circuit. If a problem is found, repair as 11 - Verify Repair Go to Step 13 necessary. Was a problem found?

Check for faulty HO2 sensor connections. If

12 OK, replace HO2 sensor. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 13 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 5

Manifold Air Temperature Absolute Pressure 4 3 2 1 (MAT/MAP) Sensor

3 4 1 2

TAN/BLK BRN WHT/RED RED/WHT

J2 08 J2 10 J2 11 J2 16

MAT 5 Volt MAP 5 Volt Engine Sensor Return Sensor Reference Control Signal Signal Module (ECM)

DTC P0107/P0108 Manifold Absolute Pressure (MAP) (Scan Diagnostics) Circuit Description The Manifold Absolute Pressure (MAP) sen- wiring harnesses related to the MAP sensor responds to changes in manifold pressure sor. A change in the MAP sensor display (vacuum). The ECM receives this information will indicate the location of the fault. as a signal voltage that will vary from about 3. With the ignition ON, engine OFF, the 0.5 volts at idle to 4.5 volts at Wide Open manifold pressure is equal to atmospheric Throttle (WOT). pressure and the signal voltage will be If the MAP sensor fails, the ECM will substitute high. This information is used by the ECM a default MAP value. as an indication of barometric pressure and The MAP sensor voltage of 5 volts is delivered is referred to as BARO. to the MAP sensor through the ECM terminal 4. If DTC P0107 is set, check for an open in J2-16. The MAP sensor will send a voltage ground circuit. signal back to the ECM on terminal J2-11 ac- 5. If a MAP sensor circuit failure is pres- cording to the manifold pressure value on the ent, the Throttle Position sensor (TPS) –if terminal. equipped– value will be used along with the Diagnostic Aids MAP sensor default value. Check for the following conditions: 6. If the ground is bad in the ECM or the 1. Poor connection at ECM. Inspect harness ground circuit has a bad connection this connectors for backed out terminals, im- could cause multiple DTC's to be set. proper mating, broken locks, improperly After repairs, clear DTC's following Clear formed or damaged terminals and poor DTC's Procedure in the General Information terminal to wire connection. section. Failure to do so may result in DTC's 2. Damaged harness. Inspect the wiring har- not properly being cleared. ness for damage. If the harness appears to be OK, observe the MAP sensor display on the scan tool while moving connectors and Section 3b- 6 Diagnostic Trouble Codes DTC P0107 Manifold Absolute Pressure (MAP) Sensor- Signal Voltage Low (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Install a scan tool 2. Start the engine and allow Engine to idle. 2 1.0v Go to Step 3 Go to Step 5 Does scan tool indicate MAP sensor voltage greater than the specified value? 1. Ignition “OFF.” 2. Disconnect MAP sensor harness connector. 3. Connect a jumper wire from harness termi- 3 4.0v Go to Step 7 Go to Step 4 nal 1 to harness terminal 2. 4. Ignition “ON,” Engine “OFF.” Does scan tool indicate MAP sensor voltage greater than the specified value? 1. Ignition “OFF.” 2. Connect a DVOM from the harness terminal 2 to a known good ground. 4 4.0v Go to Step 6 Go to Step 5 3. Ignition “ON,” Engine “OFF.” Does DVOM indicate a voltage greater than the specified value? Locate and repair open or short to ground in 5 Volt reference circuit. If a problem is found, 5 - Verify Repair Go to Step 8 repair as necessary. Was a problem found? Locate and repair open or short to ground in Map sensor signal circuit. If a problem is 6 - Verify Repair Go to Step 8 found, repair as necessary. Was a problem found? Check for plugged or leaking sensor vacuum fitting. If OK, repair faulty MAP sensor connec- 7 - Verify Repair - tions or replace MAP sensor. Is action complete? Repair faulty ECM connections or replace 8 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 7

DTC P0108 Manifold Absolute Pressure (MAP) Sensor- Signal Voltage High (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Install a scan tool 2. Start the engine and allow Engine to idle. 2 4.0v Go to Step 3 Go to Step 5 Does scan tool indicate MAP sensor voltage greater than the specified value? 1. Ignition “OFF.” 2. Disconnect MAP sensor harness connector. 3 1.0v Go to Step 4 Go to Step 6 3. Ignition “ON,” Engine “OFF.” Does scan tool indicate MAP sensor voltage less than the specified value? 1. Ignition “ON,” Engine “OFF.” 2. Connect a DVOM to terminals 2 and 4 by back probing the sensor connector. . 4 4.0v Go to Step 8 Go to Step 7 3. Ignition “ON,” Engine “OFF.” Does DVOM indicate a voltage greater than the specified value? DTC P0108 is intermittent. Locate and repair 5 - Verify Repair - intermittent faulty connections. Locate and repair short to voltage in the MAP Sensor Signal circuit. If a problem is found, 6 - Verify Repair Go to Step 9 repair as necessary. Was a problem found? Locate and repair open in the sensor ground circuit. If a problem is found, repair as neces- 7 - Verify Repair Go to Step 9 sary. Was a problem found? Check for plugged or leaking sensor vacuum fitting. If OK, repair faulty MAP sensor connec- 8 - Verify Repair - tions or replace MAP sensor. Is action complete? Repair faulty ECM connections or replace 9 faulty ECM. - Verify Repair - Is action complete? Section 3b- 8 Diagnostic Trouble Codes

Manifold Air Temperature Absolute Pressure 4 3 2 1 (MAT/MAP) Sensor

3 4 1 2

TAN/BLK BRN WHT/RED RED/WHT

J2 08 J2 10 J2 11 J2 16

MAT 5 Volt MAP 5 Volt Engine Sensor Return Sensor Reference Control Signal Signal Module (ECM)

DTC P0112/P0113 Manifold Air Temperature (MAT) Sensor (Scan Diagnostics)

Circuit Description The Manifold Air Temperature (MAT) Sensor 4. If the harness appears to be OK, observe uses a thermistor to control the signal voltage the MAT display on the scan tool while to the ECM. The ECM applies 5 volts on the moving connectors and wiring harnesses sensor circuit. When the engine is cold, the related to the MAT. A change in the MAT sensor (thermistor) resistance is high. As the display will indicate the location of the fault. engine warms up, the sensor resistance be- 5. If DTC P0113 is also set, check for an open comes lower. ground. Diagnostic Aids 6. After repairs, clear DTC’s following Clear- Check for the following conditions: ing DTC’s Procedure in the General Infor- 1. Poor connection at ECM. mation section. Failure to do so may result 2. Inspect the wire harness connectors for in DTC’s not properly being cleared. backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. 3. Inspect the wiring harness for damage. Diagnostic Trouble Codes Section 3b - 9

DTC P0112 Manifold Air Temperature (MAT) Sensor Circuit - Low Temp Indicated (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect the MAT sensor harness connector. 2 3. Ignition “ON,” Engine “OFF.” 4.0v Go to Step 4 Go to Step 3 4. Connect a DVOM by back probing terminals 3 and 4. Is voltage above the specified value? 1. Connect a one lead from the DVOM to terminal 3. 3 2. Connect the other lead of the DVOM to a 4.0v Go to Step 6 Go to Step 5 known good ground. Is voltage above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty MAT sensor. - Verify Repair - Is action complete? Locate and repair open in the MAT sensor signal circuit. If a problem is found, repair as 5 - Verify Repair Go to Step 7 necessary. Was a problem found? Locate and repair open in the sensor ground circuit. If a problem is found, repair as neces- 6 - Verify Repair Go to Step 7 sary. Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Section 3b- 10 Diagnostic Trouble Codes

DTC P0113 Manifold Air Temperature (MAT) Sensor Circuit - High Temp Indicated (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect the MAT sensor harness connector. 2 3. Ignition “ON,” Engine “OFF.” 4.0v Go to Step 3 Go to Step 4 4. Connect a DVOM by back probing terminals 3 and 4 at the sensor connector. Is the voltage above the specified value? Locate and repair intermittent faulty connec- 3 tions. If OK, replace faulty MAT sensor. - Verify Repair - Is action complete? Locate and repair short to ground in MAT signal circuit. If a problem is found, repair as 4 - Verify Repair Go to Step 5 necessary. Was a problem found? Repair faulty ECM connections or replace 5 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 11

Engine Head Temperature (EHT) Sensor

2 1

GRY GRY Harness Splice

BRN TAN

J2 10 J2 14 5 Volt EHT Engine Return Sensor Control Signal Module (ECM)

DTC P0117/P0118 Engine Head Temperature (EHT) Sensor (Scan Diagnostics) Circuit Description The Engine Head Temperature (EHT) Sensor To verify that the Thermistor is working prop- uses a thermistor to control the signal voltage erly check the approximate resistance value to the ECM. The ECM applies 5 volts on the with an ohms tester using the table below as a sensor circuit. When the engine is cold, the guide. sensor (thermistor) resistance is high. As the engine warms up, the sensor resistance becomes lower. Temperature Temperature Resistance Diagnostic Aids °C °F Ohms Check for the following conditions: -10 14 58,506 1. Poor connection at ECM. 0 32 33,723 2. Inspect the wire harness connectors for 10 50 20,210 backed out terminals, improper mating, 20 68 12,542 broken locks, improperly formed or damaged terminals and poor terminal to wire 30 86 8,032 connection. 40 104 5,292 3. Inspect the wiring harness for damage. 50 122 3,578 4. If the harness appears to be OK, observe 60 140 2,477 the EHT Sensor display on the scan tool 80 176 1,263 while moving connectors and wiring har- 90 194 927 nesses related to the EHT Sensor. A 110 230 525 change in the EHT Sensor display will indi- 120 248 403 cate the location of the fault. 135 275 278 5. If DTC P0118 is also set, check for an open 145 293 221 ground 155 311 177 6. After repairs, clear DTC's following Clear- 175 347 117 ing DTC's Procedure in the General Infor- 185.0 365.0 96.73 mation section. Failure to do so may result in DTC’s not properly being cleared. Section 3b- 12 Diagnostic Trouble Codes

DTC P0117 Engine Head Temperature (EHT) Sensor Circuit - Low Temp Indicated (Scan Diagnostics)

DTC P0118 Engine Head Temperature (EHT) Sensor Circuit - High Temp Indicated (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “ON,” Engine “OFF.” 2. Connect the DVOM to terminals J2-10 and 1.2- 2 Go to Step 3 Go to Step 4 J2-14 in the ECM connector. 4.5v Is voltage within the specified value? Locate and repair intermittent faulty connec- 3 tions. If OK, replace faulty EHT sensor. - Verify Repair - Is action complete? Locate and repair short to ground in the EHT sensor signal circuit. If a problem is found, 4 - Verify Repair Go to Step 5 repair as necessary. Was a problem found? Repair faulty ECM connections or replace 5 faulty ECM. - Verify Repair - Is action complete? Section 3b- 14 Diagnostic Trouble Codes

2 2 1 Throttle 3 Position (TPS) Sensor

RED/WHT BRN PNK/BLK

J2 16 J2 10 J2 12

5 Volt 5 Volt TPS Engine Reference Return Sensor Control Signal Module (ECM)

DTC P0122/P0123 Model 490000 Throttle Position Sensor (TPS) If equipped (Scan Diagnostics) Circuit Description The Throttle Position Sensor (TPS) is a poten- the scan tool while moving connectors and tiometer connected to the throttle shaft on the wiring harnesses related to the MAP sen- throttle body. By monitoring the voltage on the sor. A change in the MAP sensor display signal line, the ECM calculates throttle posi- will indicate the location of the fault. tion. As the throttle valve angle is changed, the 3. If the ground is bad in the ECM or has a TPS signal also changes. At a closed throttle bad connection this could cause multiple position, the output of the TPS is low. As the DTC's to be thrown. throttle valve opens, the voltage output in- After repairs, clear DTC's following the Clear creases so that at Wide Open Throttle (WOT) DTC's Procedure in the General Information the output voltage should be above 4 volts. section. Failure to do so may result Diagnostic Aids In DTC's not properly being cleared. Check for the following conditions: 1. Poor connection at ECM. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal to wire connection. 2. Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP sensor display on Diagnostic Trouble Codes Section 3b - 15

DTC P0112 Model 490000 Throttle Position Sensor (TPS) Circuit - Signal Voltage Low (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Throttle closed. 2. Ignition “ON,” Engine “OFF.” 2 0.36v Go to Step 3 Go to Step 5 Does scan tool indicate TPS voltage less than the specified value? 1. Ignition “OFF.” 2. Disconnect the TPS harness connector. 3. Connect a jumper wire from harness termi- 3 nal 2 to harness terminal 3. 4.0v Go to Step 7 Go to Step 4 4. Ignition “ON,” Engine “OFF.” Does the scan tool indicate a TPS voltage greater than the specified value? 1. Ignition “OFF.” 2. Connect a DVOM from the harness terminal 2 to a known good ground. 4 4.0v Go to Step 6 Go to Step 5 3. Ignition “ON,” Engine “OFF.” Does scan tool indicate a TPS voltage greater than the specified value? Locate and repair open or short to ground in the 5v reference circuit. If a problem is found, 5 - Verify Repair Go to Step 8 repair as necessary. Was a problem found? Locate and repair open or short to ground in TPS signal circuit. If a problem is found, repair 6 - Verify Repair Go to Step 8 as necessary. Was a problem found? Repair faulty TPS connections or replace 7 faulty TPS. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 8 faulty ECM. - Verify Repair - Is action complete? Section 3b- 16 Diagnostic Trouble Codes

DTC P0123 Model 490000 Throttle Position Sensor (TPS) Circuit - Signal Voltage High (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD 1 - Go to Step 2 tem checked? System Check 1. Throttle closed. 2. Ignition “ON,” Engine “OFF.” 2 4.0v Go to Step 3 Go to Step 5 Does scan tool indicate TPS voltage greater than the specified value? 1. Ignition “OFF.” 2. Disconnect TPS harness connector. 3 3. Ignition “ON,” Engine “OFF.” 0.36v Go to Step 4 Go to Step 5 Does scan tool indicate a voltage less than the specified value? Connect DVOM from harness terminal 1 to harness terminal 2. 4 4.0v Go to Step 7 Go to Step 6 Does DVOM indicate a voltage greater than the specified value? Locate and repair short to voltage in the TPS signal circuit. 5 - Verify Repairs Go to Step 8 If a problem is found, repair as necessary. Was a problem found? Locate and repair open in the sensor ground circuit. If a problem is found, repair as neces- 6 - Verify Repairs Go to Step 8 sary. Was a problem found? Repair faulty TPS connections or replace 7 faulty TPS. - Verify Repairs - Is action complete? Repair faulty ECM connections or replace 8 faulty ECM. - Verify Repairs - Is action complete? Diagnostic Trouble Codes Section 3b - 17

2 2 1 Throttle 3 Position (TPS) Sensor

BRN RED/WHT PNK/BLK

J2 10 J2 16 J2 12

5 Volt 5 Volt TPS Engine Return Reference Sensor Control Signal Module (ECM)

DTC P0122/P0123 Model 610000 Throttle Position Sensor (TPS) (Scan Diagnostics)

DTC P0122 Model 610000Throttle Position Sensor (TPS) Circuit - Signal Voltage Low (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition “OFF.” 2. Disconnect TPS harness connector. 3. Connect a jumper wire from harness terminal 1 to harness terminal 3. 2 - Go to Step 4 Go to Step 3 4. Start engine and idle for 2 minutes or until DTC tool indicates a stored DTC. 5. Ignition “ON,” engine “OFF.” Is DTC PO123 present? 1. Remove jumper wire from terminals 1 and 3. 3 2. Connect DVOM by back probing harness 4.0v Go to Step 5 Go to Step 6 terminals 1 and 2 on the sensor connector. Is voltage reading above the specified value? Locate and repair intermittent faulty connec- 4 tions. If OK, replace faulty TPS. - Verify repair - Is action complete? Locate and repair open or short to ground in the TPS signal circuit. If a problem is found, 5 - Verify repair Go to Step 7 repair as necessary. Was a problem found? Locate and repair open or short to ground in 6 the 5v reference circuit. - Verify repair Go to Step 7 Was a problem found? Repair faulty ECM connections or replace 7 faulty ECM. - Verify repair - Is action complete? Diagnostic Trouble Codes Section 3b - 19

DTC P0123 Model 610000 Throttle Position Sensor (TPS) Circuit - Signal Voltage High (Scan Diagnostics)

DABC

Heated Oxygen Sensor

VIO WHT GRY BLK Inline A B C D Connector

RED WHT/ GRY/ BRN GRN BLK From MPR (Main Power Relay) J2 07JJ2 17 2 10

Oxygen Oxygen 5 Volt Engine Sensor Sensor Return Control Heater Signal Module Low Control (ECM)

DTC P0131/P0132 Oxygen (HO2) Sensor If equipped (Scan Diagnostics) Circuit Description Diagnostic Aids

The Heated Oxygen (HO2) sensor(s) varies Check for the following conditions: voltage within a range from about 1.0 volt if the Poor connection in harness. Inspect harness exhaust is rich, down to about 0.1 volt if the connectors for backed out terminals, improper exhaust is lean. mating, broken locks, improperly formed or The sensor behaves like an open circuit and damaged terminals and poor terminal to wire produces no voltage when the exhaust tem- connection. perature is below 360° C (600°F). An open For proper wire and connection repairs, refer oxygen sensor circuit or cold oxygen sensor to Wiring Repair. After repairs, clear DTC’s causes an Open Loop operation. following “Clear DTC’s Procedure.” Failure to The heater in the sensor provides for a faster do so may result in DTC’s not properly being sensor warm-up. This allows the sensor(s) to cleared. become active in a shorter period of time and remain active during a long extended idle. DTC P0131 determines if the heated oxygen sensor has developed an open circuit. With an active DTC P0131 set, the system operates in an Open Loop mode and the Malfunction Indicator Lamp (MIL) is turned on. Diagnostic Trouble Codes Section 3b - 21

DTC P0131 Heated Oxygen Sensor Low Voltage- Lean Exhaust indicated (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) sys- Go to OBD 1 - Go to Step 2 tem check performed? System check 1. Connect scan tool. 2. Run the Engine at normal operating temperature. 2200 rpm 2 3. Increase the engine speed to a specified Go to Step 3 Go to Step 4 value. 0.10v

Is the HO2 sensor voltage displayed less than the specified value. Using a jumper wire, connect terminal B of

the HO2 sensor to a known good ground. Wait 15 seconds for the voltage to settle. 0.10- Refer to Diag- 3 Go to Step 5 Does the scan tool HO2 sensor voltage dis- 0.49v nostic Aids play indicate a voltage within the specified value? If no additional DTC’s are stored. Refer to Go to Applica- 4 the Diagnostic Aids. If any additional DTC’s - - ble DTC Table are stored, refer to those table(s) first.

Locate and repair short to ground in the HO2 sensor signal circuit. If a problem is found, 5 - Verify Repair Go to step 6 repair as necessary. Was a problem found? Repair faulty ECM connections or replace 6 faulty ECM. - Verify repair - Is action complete? Section 3b- 22 Diagnostic Trouble Codes

DTC P0132 Heated Oxygen Sensor High Voltage- Rich Exhaust indicated (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Connect scan tool. 2. Run the engine at normal operating temperature. 2200 3. Increase the engine speed to specified RPM 2 Go to Step 3 Go to Step 5 value.

Does the scan tool HO2 Sensor voltage dis- 0.900v play indicate a voltage above the specified value? Ignition “ON,” Engine “OFF.” Refer to Does the scan tool HO Sensor voltage dis- 3 2 0.900v Go to Step 4 Diagnostic play indicate a voltage above the specified Aids value?

1. Disconnect the HO2 sensor electrical connector. 2. Ignition “ON,” Engine “OFF.” 4 0.900v Go to Step 6 Go to Step 7 Does the scan tool HO2 Sensor voltage display indicate a voltage above the specified value? If any additional DTC’s are stored, refer to Go to 5 those table(s) first. - Applicable - DTC Table

Repair faulty HO2 sensor connections or re- 6 place HO2 sensor. - Verify Repair - Is action complete?

DTC P0174 PE System Lean (Non-Scan Diagnostics)

Replace faulty HO2 Sensor. Contact 8 Is action complete? - Verify Repair Engine Manufacturer Section 3b- 24 Diagnostic Trouble Codes

From MPR (Main Power Relay)

B A RED RED A A

Fuel Fuel Injector Injector Cylinder #1 Cylinder #2

B B

LT. BLU/BLK LT. BLU/WHT J2 05 J2 06

Injector Injector Engine Driver A Driver B Control Module (ECM)

DTC P0201/P0202 Fuel Injectors A and B (Scan Diagnostics) Circuit Description Diagnostic Aids The fault code will indicate which injector is in Check for the following conditions: fault mode. 1. Poor connection at ECM. The Engine Control Module (ECM) controls 2. Inspect the wire harness connectors for fuel injector drivers that are located inside the backed out terminals, improper mating, ECM. An ignition voltage is supplied to the fuel broken locks, improperly formed or dam- injectors. The ECM controls each fuel injector aged terminals and poor terminal to wire by grounding the control circuit via a solid state connection. device called a driver. If the ECM detects an 3. Inspect the wiring harness for damage. incorrect voltage for the commanded state of 4. Check the fuse block for an open fuse. the driver, a fuel injector control DTC will set. After repairs, clear DTC’s following Clearing When a DTC is set it will only indicate which DTC’s Procedure in the General Information fuel injector(s) has a fault. The technician will section. Failure to do so may result in DTC’s have to diagnose if it is a fault in the ground not properly being cleared. circuit or ignition circuit. Important: The ECM/fuel injector fuse also supplies voltage to the ignition coils. If the fuse is open, inspect all related circuits for a short to ground. NOTE: If an ignition coil fault code is active it will turn off the fuel injector for the same cylinder(s) the ignition coil is related to. Diagnostic Trouble Codes Section 3b - 25

DTC P0201/ P0202 Fuel Injectors High, Low or Open (Scan Diagnostics)

2 EFI Fuel 1 M Pump Module

2 1 RED BLU/ From MPR YEL (Main Power Relay) J2 09 Fuel Pump Engine Control Control Module (ECM)

DTC P0230/P0232 Model 490000 Fuel Pump Relay (FPR) (Scan Diagnostics) Circuit Description Diagnostic Aids Certain engine models do not use a relay to The following conditions may have caused the operate the fuel pump. On these models the fuel pump fuse to malfunction: Engine Control Module (ECM) controls the fuel 1. The fuse is faulty pump module with an internal switch called a 2. There is an intermittent short in the fuel driver. The primary function of the driver is to pump power feed circuit. supply the ground to the fuel pump module. 3. The fuel pump has an intermittent internal This driver has a fault line which the ECM problem. monitors. 4. Poor connection at ECM. If the fault detection circuit senses a voltage 5. Inspect the wire harness connectors for other than what the ECM expects, the fault line backed out terminals, improper mating, status changes causing the DTC to set. broken locks, improperly formed or damaged terminals and poor terminal to wire Improper fuel system pressure results in one connection. or many of the following symptoms: 6. Inspect the wiring harness and relay for • Cranks but will not run damage. • Cuts out, may feel like an ignition problem 7. Check the fuse block for an open fuse. • Poor fuel economy After repairs, clear DTC’s following Clearing • Loss of power DTC’s Procedure in the General Information • Hesitation section. Failure to do so may result in DTC’s • DTC’s not properly being cleared. Diagnostic Trouble Codes Section 3b - 27

DTC P0230/P0232-Fuel Pump Relay (FPR) model 49000 (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition ”ON,” Engine “OFF.” 2. Using a DVOM connected to a known good ground, back probe terminal 2 of the 12.0- 2 Go to Step 3 Go to Step 5 fuel pump module harness connector. 13.5v Is the voltage displayed above the specified value? 1. Using a test light connected to a B+, back probe terminal 1 of the fuel pump module harness connector. 3 - Go to Step 6 Go to Step 4 2. Attempt to start engine. Does the test lamp illuminate brightly while cranking? Locate and repair an open or short to voltage 4 in the fuel pump module ground circuit. - Verify Repair Go to Step 7 Was a problem found? Locate and repair an open or short to ground 5 in the fuel pump module ignition (B+) circuit. - Verify Repair - Was a problem found? Repair faulty fuel pump module connections 6 or replace faulty fuel pump module. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Section 3b- 28 Diagnostic Trouble Codes

From MPR (Main Power Relay) Fuel Pump Relay RED 2 8 2 1 RED RED 1 7 2 2

EFI Fuel Fuel Lift Pump M Pump Module M (Low Pressure) BLU/YEL (High Pressure) J2 09 1 1 Fuel Pump Engine BLK BLK 20a Fuse Control Control Battery Module (ECM) 6 54321

12 11 10 987

15a Fuse Fuel Pump Ignition Main Power Relay Relay DTC P0230/P0232 Model 610000 Fuel Pump Relay FPR (Scan Diagnostics)

Circuit Description Diagnostic Aids When the ignition switch is ON, the ECM ac- The following conditions may have caused the tivates the electric fuel pump module and the fuel pump fuse to malfunction: electric lift pump. The lift pump is a diaphragm 1. The fuse is faulty style pump that transfers fuel from the tank to 2. There is an intermittent short in the fuel the fuel pump module. The fuel pump module pump power feed circuit. and lift pump will remain ON as long as the 3. The fuel pump has an intermittent internal ECM receives reference pulses from the crank problem. sensor. If there are no reference pulses, the 4. Poor connection at ECM. ECM turns the fuel pump relay OFF after about 5. Inspect the wire harness connectors for 2 seconds. This shuts off the fuel pumps. The backed out terminals, improper mating, bro- fuel pump module delivers fuel to the fuel rail ken locks, improperly formed or damaged and injectors. The fuel pump module also has terminals and poor terminal to wire connec- an internal fuel pressure regulator, that main- tion. tains a fuel pressure of 39 PSI or 270 KPA. 6. Inspect the wiring harness and relay for Improper fuel system pressure results in one damage. or many of the following symptoms: 7. Check the fuse block for an open fuse. • Cranks but will not run After repairs, clear DTC’s following Clearing • Cuts out, may feel like an ignition problem DTC’s Procedure in the General Information • Poor fuel economy section. Failure to do so may result in DTC’s • Loss of power not properly being cleared. • Hesitation • DTC’s Diagnostic Trouble Codes Section 3b - 29

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Ignition ”ON,” Engine “OFF.” 2. Command the relay on and off using the 2 scan tool. - Go to Step 3 Go to Step 5 Does the relay turn ON and OFF when commanded? 1. Ignition “OFF.” 2. Disconnect the ECM connector J2(Black). 3. Install a 5 amp fused jumper wire from a known good ground to the control circuit at the ECM harness connector (J2-09). 4. Ignition ”ON,” Engine “OFF.” Go to Important: Replace the relay if the DVOM 3 0.75A Diagnostic Go to Step 4 goes to 0 during the current draw test. Aids 5. Using a DVOM on 40 amp scale, measure the current from the relay control circuit in the ECM harness connector to ground for 2 minutes. Does the current draw measure less than the specified value? 1. Ignition “OFF.” 2. Disconnect the fuel pump relay connector. 3. Using a DVOM, measure the resistance 4 from the relay control circuit in the ECM - Go to Step 10 Go to Step 8 harness connector to ground. Does the DVOM display infinite resistance or OL? 1. Ignition “OFF.” 2. Disconnect the fuel pump relay connector. 3. Connect a test lamp between the fuel pump relay control circuit and the fuel pump relay ignition feed circuit, on the coil side of the relay, at the fuel pump relay 5 - Go to Step 10 Go to Step 6 harness connector. 4. Ignition ”ON,” Engine “OFF.” 5. Using a scan tool, command the relay ON and OFF. Does the test lamp turn ON and OFF when commanded? Section 3b- 30 Diagnostic Trouble Codes

DTC P0230/P0232 Fuel Pump Relay Driver Circuit High, Low or Open cont’d (Scan Diagnostics)

Step Action Value(s) Yes No Using a test lamp connected to ground, probe the ignition feed circuit, on the coil side of the 6 - Go to Step 7 Go to Step 9 fuel pump relay harness connector. Is the test lamp illuminated? 1. Ignition “OFF.” 2. Reconnect the relay. 3. Disconnect the ECM connector J2. 4. Ignition ”ON,” Engine “OFF.” 5. Using a fused jumper wire connected to 7 - Go to Step 11 Go to Step 8 ground, momentarily probe the relay control circuit in the ECM harness connector. Does the relay turn ON when the circuit is grounded and OFF when the circuit is opened? Repair the faulty relay control circuit. 8 - Verify Repair - Is action complete? Repair the faulty relay ignition feed circuit. 9 - Verify Repair - Is action complete? Repair faulty relay connections or replace 10 faulty relay. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 11 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 31

TARGET WHEEL Crank Position (CKP) Sensor VR Sensor 1 23X Inline 2 1 Connector BLK/ GRN/ WHT WHT

Twisted Cable Pair

BLK/ GRN/ WHT WHT

2 2 13

CKP CKP Engine 23X 23X Control VR HI VR LO Module (ECM)

DTC P0336/P0337 Crankshaft Position (CKP) Sensor (Scan Diagnostics) Modes of Operation Diagnostic Aids The crankshaft position (CKP) sensor works in Check for the following conditions: conjunction with the 23X reluctor target wheel 1. Verify that the Crank Position Sensor is on the flywheel. Each tooth on the reluctor gapped at .30 from the target wheel. wheel is equally spaced with 1 tooth missing 2. Poor connection at ECM. Inspect harness for the reference sync pulse. As the crankshaft connectors for backed out terminals, im- rotates, the reluctor target wheel interrupts a proper mating, broken locks, improperly magnetic field produced by a magnet internal formed or damaged terminals and poor to the sensor. The CKP sensor internal cir- terminal to wire connection. cuitry detects this interruption of the magnetic 3. Damaged harness. Inspect the wiring har- field, and produces an ON/OFF AC voltage of ness for damage. If the ground is bad in the varying frequency. The frequency of the CKP ECM or has a bad connection this could sensor output signal is dependent upon crank- cause multiple DTC’s to be thrown. shaft speed. The ECM uses each CKP output After repairs, clear DTC’s following clear signal to determine crankshaft speed, and DTC’s Procedure in the General Information identify crankshaft position. section. Failure to do so may result in DTC’s There is one normal mode of operation, with not properly being cleared. the spark under control of the ECM. If the CKP signal is lost the engine will not run. The ECM will not be able to determine which stroke the pistons are on. Diagnostic trouble codes are available to accurately diagnose the ignition system with the scan tool. Section 3b- 32 Diagnostic Trouble Codes

DTC P0336/P0337 Crankshaft Position (CKP) Sensor (Scan Diagnostics)

Step Action Value(s) Yes No Did you perform the “On-Board Diagnostic” Go to 1 (OBD) System Check? - Go to Step 2 OBD System Check 1. Ignition “OFF.” 2. Back probe the ECM connector at terminals J2-04 and J2-13. 3. Using a DVOM set to AC voltage turn over the engine. Disconnect the ignition coils to 2 Go to Step 7 Go to Step 3 stop it from running while your turning the 0.95v engine over with the starter. Does the DVOM indicate that the CKP is giving off an AC voltage above the specified value? 1. Ignition “OFF.” 2. Back probe the CKP sensor connector at terminals 1 and 2. 3. Using a DVOM set to AC voltage turn over 3 Go to Step 4 Go to Step 5 the engine. 0.95v Does the DVOM indicate that the CKP is giving off an AC voltage above the specified value? Locate and repair short or open in the CKP circuit. If a problem is found, repair as neces- 4 - Verify Repair Go to Step 5 sary. Was a problem found? Verify the CKP is clean and mounted cor- 5 rectly. - Verify Repair Go to Step 6 Was a problem found? Repair faulty CKP connections or replace 6 faulty CKP. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 7 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 33

From MPR (Main Power Relay)

YEL YEL AB Inline Inline B A Connector B A Connector

Ignition Ignition Ignition Coil Coil Ignition Coil Coil Cylinder #1 Cylinder #2

Spark Plugs Spark Plugs

VIO/BLK VIO/WHT

J2 01 J1 10 Ignition Ignition Engine Coil Coil Control Driver A Driver B Module (ECM)

DTC P0351/P0352 Ignition Coil A and B (Scan Diagnostics) Circuit Description Each ignition coil has an ignition (B+ volt- continue to run on one cylinder if no fault is set age) and a ground circuit. The engine control for the opposite cylinder. module (ECM) supplies an ignition control (IC) If there is no spark and a DTC has NOT set circuit and a low reference circuit. Each igni- check the coil wire to the spark plug for good tion coil contains a solid state driver module connectivity. that is located inside the ECM. The ECM will Important: The ECM/ignition coil fuse also command the IC circuit ON, which allows the supplies voltage to the fuel injectors. If the fuse current to flow through the primary coil wind- is open, inspect all related circuits for a short ings for the appropriate time or dwell. When to ground. the ECM commands the IC circuit OFF, this Diagnostic Aids will interrupt current flow through the primary Check for the following conditions: coil windings. The magnetic field created by 1. Poor connection at ECM. the primary coil windings will collapse across 2. Inspect the wire harness connectors for the secondary coil windings, which induces a backed out terminals, improper mating, bro- high voltage across the spark plug electrodes. ken locks, improperly formed or damaged The primary coils are current limited to prevent terminals and poor terminal to wire connec- overloading if the IC circuit is held ON for an tion. extended time. 3. Inspect the wiring harness for damage. The fault code will indicate which coil is in 4. Check the fuse block for an open fuse. fault. After repairs, clear DTC’s following Clearing When an ignition coil fault is set the ECM will DTC’s Procedure in the General Information also shut down the fuel injector for the same section. Failure to do so may result in DTC’s cylinder that the fault is set on. The engine will not properly being cleared. Section 3b- 34 Diagnostic Trouble Codes

DTC P0351/P0352 Ignition coil(s) High, Low or Open (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Disconnect the appropriate harness connector for each fuel injector. 2. Ignition ”ON,” Engine “OFF.” 3. Using a test lamp connected to a known 2 - Go to Step 3 Go to Step 6 good ground, back probe terminal A of each ignition coil harness connector. Does the test lamp illuminate on both harness connectors? 1. Connect the test lamp to B+; back probe terminal B of each ignition coil harness connector. 3 - Go to Step 4 Go to Step 5 2. Attempt to start engine. Does the test lamp blink on both harness connectors? 1. Ignition ”ON,” Engine “OFF.” 2. Connect the test lamp to B+; back probe terminal B of each ignition coil harness 4 connector. DO NOT attempt to start the - Go to Step 7 Go to Step 8 engine. Does the test lamp remain illuminated at all times on either of the ground circuits? Locate and repair an open or short to voltage 5 in the ground circuit. - Verify Repair Go to Step 9 Was a problem found? Locate and repair an open or short to ground 6 in the ignition (B+) circuit. - Verify Repair - Was a problem found? Locate and repair a short to ground in the 7 ground circuit. - Verify Repair Go to Step 9 Was a problem found? Repair faulty fuel injector connections or re- 8 place faulty fuel injector. - Verify Repair - Is action complete? Repair faulty ECM connections or replace 9 faulty ECM. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 35

D C B A Idle Air Control (IAC) Valve

A C B D

BLU/RED BLU/GRN BLU/GRY BLU/BRN

J1 13JJ1 11 J1 12 1 01

IAC B IAC A IAC B IAC A Engine Low Low High High Control Control Control Control Control Module (ECM)

DTC P0505 Idle Air Control (IAC) Valve If equipped (Scan Diagnostics)

DTC P0505 Idle Air Control (IAC) Valve Test (Scan Diagnostics)

Main Power Relay For Fuse/Relay block 4/C 10/F pictorial refer to section 3-11 3/D 9/E 20a Fuse Battery

6 524 3 1 20 AMP Fuse 789101112

15a Fuse Fuel Pump Ignition Main Power Relay Ignition Switch Relay RED 15 AMP Fuse

REDRED REDBLK + -

Battery J2 15J1 17 J2 18J1 09 12V GND IGN MPR Battery Ground Engine Control Module (ECM)

DTC P0562/P0563 System Voltage (Scan Diagnostics) Circuit Description The EFI system operates with a battery volt- To further diagnose system voltage faults, refer age from 9 to 16 volts. If the system voltage to Briggs & Stratton Intec V-Twin Cylinder OHV drops below 6.2 volts the ECM will reset. The Repair Manual section 7. Malfunction Indicator Light (MIL) will illuminate Diagnostic Aids if the voltage is below 9 volts or above 16 volts Check for the following conditions: for a specified amount of time during normal 1. Poor connection at ECM. Inspect harness operation. connectors for backed out terminals, im- To determine the system voltage to the ECM, a proper mating, broken locks, improperly voltage measurement can be taken at a termi- formed or damaged terminals and poor nal J2-18. If the voltage at terminal J2-18 is not terminal to wire connection. within 0.01 volt of the measurement you get at 2. Damaged harness. Inspect the wiring har- the battery (measuring between the positive(+) ness and connectors for damage. and negative(-) posts of the battery with your 3. Check the fuse block for an open fuse. DVOM), determine the fault associated with After repairs, clear DTC’s following Clear circuit J2-18. DTC’s Procedure in the General Information Similarly, you should be able to measure bat- section. Failure to do so may result in DTC’s tery voltage on terminal J2-15 with the ignition not properly being cleared. switch in the on position and the engine not running. Refer to the diagram above to locate the two terminals on the ECM that provide battery voltage and ignition-on voltage. Section 3b- 38 Diagnostic Trouble Codes

DTC P0562/P0563 System voltage (Scan Diagnostics)

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) System Go to OBD 1 - Go to Step 2 checked? System Check 1. Key “OFF” Engine “OFF.” 2. Check the battery for voltage with a 12.2- 2 Go to Step 3 Go to Step 5 DVOM. 13.5v Is the battery within specified value? 1. Ignition “OFF” Engine “OFF.” 2. Check if the ECM has battery voltage at ECM terminal J2-18 with a DVOM con- 3 - Go to Step 4 Go to Step 9 nected to a known good ground. Was the voltage within 0.3v of the battery voltage? 1. Ignition “ON” Engine “OFF.” 2. Check for ignition voltage at ECM terminal J2-15 with a DVOM connected to a known 4 - Go to Step 5 Go to Step 10 good ground. Was the voltage within 0.3v of the battery voltage? Check charging system. Refer to Briggs & Stratton manual for intec V-Twin Cylinder OHV 5 - Go to Step 7 Go to Step 6 Repair Manual section 7 Is the charging system OK? Locate and repair charging system. Refer to Briggs & Stratton manual for intec V- 6 - Verify Repair - Twin Cylinder OHV Repair Manual section 7 Is action complete? Verify good continuity at the battery terminals. 7 - Verify Repair Go to Step 8 Repair if necessary. Replace battery. 8 - Verify Repair - Is action complete? Locate and repair an open or short to ground 9 in the battery feed circuit. - Verify Repair - Is action complete? Locate and repair an open or short to voltage 10 in the ignition feed circuit. - Verify Repair - Is action complete? Diagnostic Trouble Codes Section 3b - 39

1.4W Lamp or LED with resister O

IGN

ORG/BLK

J1 03 MIL Engine Control Module (ECM)

DTC P0650 Malfunction Indicator Lamp (MIL) Diagnosis (Scan Diagnostics)

DTC P0650 Malfunction Indicator Light (MIL) Malfunction (Scan Diagnostics)

Symptoms Important Preliminary Checks • Improperly formed or damaged terminals Before using this section you should have and/or connectors. performed the On-Board Diagnostic (OBD) • All connector terminals in the problem cir- System Check and determined that: cuit should be carefully checked for proper • The ECM and MIL (Malfunction Indicator contact tension. Lamp) are operating correctly. • Poor terminal to wire connection (crimping). • There are no DTC(s) stored. The unit may be operated with a Digital Volt Verify the customer complaint and locate Ohmmeter connected to a suspected circuit. the correct symptom in the table of contents. An abnormal voltage when malfunction occurs Check the items indicated under that symptom. is a good indication that there is a fault in the Visual/Physical Check circuit being monitored. Several of the symptom procedures call for A scan tool may also be used to help detect a careful Visual/ Physical Check. The im- intermittent conditions. portance of this step cannot be stressed too To check loss of DTC memory, disconnect strongly - it can lead to correcting a problem MAP sensor and idle engine until the MIL without further checks and can save valuable comes ON. DTC P0107 should be stored time. This check should include: and kept in memory when ignition is turned • ECM grounds and sensor connections for OFF. If not the ECM is faulty. When this test is being clean, tight and in their proper loca- completed, make sure that you clear the DTC tion. P0107 from memory using “Clearing DTC Pro- • Check thoroughly for any type of vacuum cedure” found in General Information section. leak or restriction. An intermittent MIL with no stored DTC may be • Air leaks at throttle body mounting area caused by the following: and intake manifold sealing surfaces. • Ignition coil shorted to ground and arcing at • Ignition wires for cracking, hardness, prop- ignition wires or plugs. er routing and carbon tracking. • MIL wire to ECM shorted to ground. • Wiring for proper connections, pinches and • Poor ECM grounds. cuts. If wiring harness or connector repair • Check for an electrical system interference is necessary, refer to General Information caused by a sharp electrical surge. Normal- section for correct procedure. ly, the problem will occur when the faulty • Moisture in primary or secondary ignition component is operated. circuit connections. • Check for secondary ignition components • Salt corrosion on electrical connections and shorted to ground, or an open ignition coil exposed throttle body linkages. ground. Intermittents • Check for components internally shorted Important: Problem may or may not turn “ON” to ground such as starters, alternators or the Malfunction Indicator Lamp (MIL) or store relays. a DTC. DO NOT use the Diagnostic Trouble If problem has not been found go to ECM Code (DTC) tables for intermittent problems. Connector Symptom Tables at the end of The fault must be present to locate the prob- Symptoms section. lem. Many intermittent problems are caused by faulty electrical connections or wiring. Perform careful visual physical check. Check for the following conditions: • Poor mating of the connector halves, or a terminal not fully seated in the connector body (backed out or loose). Symptoms Section 4 - 3

Engine Will NOT Crank

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD Sys- 1 - Go to Step 2 tem checked? tem Check Was the visual/physical check performed? Go to Visual/ 2 - Go to Step 3 Physical Check Check the battery following conditions. • Loose or corroded terminals • Verify the battery voltage is within the 12.2- Symptom 3 Go to Step 4 specified range. 13.5v Fixed If a problem is found, repair as necessary. Will the engine crank over? Verify the PTO clutch is not engaged. If the Symptom 4 PTO clutch is engaged disengage it. - Go to Step 5 Fixed Will the engine crank over? Verify the safety interrupt is NOT active or faulty (if equipped). If a problem is found, re- Symptom 5 - Go to Step 6 pair as necessary. Fixed Will the engine crank over? Verify the ignition switch is working properly. Refer to Intek V-Twin Cylinder OHV repair Symptom 6 Manual Section 2. If a problem is found, repair - Go to Step 7 Fixed as necessary. Will the engine crank over? Verify the starter is operating properly. Refer to Intek V-Twin Cylinder OHV repair Manual Symptom 7 - Go to Step 8 Section 6. Fixed Will the engine crank over? 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and no malfunctions have been found, review/ inspect the following: Symptom Contact Engine 8 - • Visual inspection. Fixed Manufacturer • Scan tool data/ Code reader data • All electrical connections within a suspected circuit and/or system. Will the engine crank over? Section 4- 4 Symptoms

Engine Cranks But Will NOT Start

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD Sys- 1 - Go to Step 2 tem checked? tem Check Was the visual/physical check performed? Go to Visual/ 2 - Go to Step 3 Physical Check Verify fuel in the tank(s). If a problem is found, Symptom 3 repair as necessary. - Go to Step 4 Fixed Does the engine start? Check fuel shut off valve (if equipped). If the Symptom 4 valve is closed turn it to the open position. - Go to Step 5 Fixed Does the engine start? Check the following fuel systems for debris, water, or contaminants. • Fuel tanks • Fuel filter Symptom 5 - Go to Step 6 • Fuel lines Fixed • Fuel pumps If a problem is found, repair as necessary. Does the engine start? Verify the fuel pumps are operating properly with a fuel pressure test. Refer to section 2 35-43 Symptom 6 page 10 for test procedure. If a problem is Go to Step 7 PSI Fixed found, repair as necessary. Does the engine start? Verify the Safety interrupt Is NOT active or faulty. If a problem is found, repair as neces- Symptom 7 - Go to Step 8 sary. Fixed Does the engine start? Check the battery for the following conditions. • Loose or corroded terminals • Verify the battery voltage is within the 12.2- Symptom 8 Go to Step 9 specified voltage range. 13.5v Fixed If a problem is found, repair as necessary. Does the engine start and continue to run? Verify that each cylinder is getting spark. Re- fer to Intek V-Twin Cylinder OHV repair Man- Symptom 9 ual Section 2 for test procedure. If a problem - Go to Step 10 Fixed is found, repair as necessary. Does the engine start? Symptoms Section 4 - 5

Engine Cranks But Will NOT Start cont’d

Step Action Value(s) Yes No Verify the ECM is powering up. Refer to section 3 for procedure. If a problem is found, Symptom 10 - Go to Step 11 repair as necessary. Fixed Does the engine start? Check the engine for the following mechanical problems: • Low compression. • Leaking cylinder head gaskets. Symptom 11 • Proper valve set up. - Go to Step 12 Fixed Refer to Intek V-Twin Cylinder OHV repair Manual Section for test procedures. If a problem is found, repair as necessary. Does the engine still have low power output? 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and no malfunctions have been found, review/ inspect the following: Symptom Contact Engine 12 • Visual inspection. - Fixed Manufacturer • Scan tool data/ Code reader data • All electrical connections within a suspected circuit and/or system. If a problem is found, repair as necessary. Does the engine start? Section 4- 6 Symptoms

Hard Start Symptoms Definition: Engine cranks OK, but does not start for a long time. Does run, or may start but immediately dies.

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD 1 - Go to Step 2 tem checked? System Check Was the visual/physical check performed? Go to Visual/ 2 - Go to Step 3 Physical Check Check the following fuel systems for debris, water, or contaminants. • Fuel tanks • Fuel filter Symptom 3 - Go to Step 4 • Fuel lines Fixed • Fuel pumps If a problem is found, repair as necessary. Does the engine start and continue to run? Check for proper fuel pressure. Refer to section 2 for the test procedure. If a problem is 35-43 Symptom 4 Go to Step 5 found, repair as necessary. PSI Fixed Does the engine start and continue to run? Check the battery for the following conditions. • Loose or corroded terminals • Verify that the battery voltage is within the 12.2- Symptom 5 Go to Step 6 specified range. 13.5v Fixed If a problem is found, repair as necessary. Does the engine start and continue to run? Check for intermittent opens or shorts to ground in the MAP sensor circuit. If a problem Symptom 6 - Go to Step 7 is found, repair as necessary. Fixed Does the engine start and continue to run? 1. Check for proper operation of the TPS (if equipped). 2. Verify the throttle linkage is not sticking, Symptom 7 binding or worn causing the TPS voltage - Go to Step 8 Fixed to be higher than normal. If a problem is found, repair as necessary. Does the engine start and continue to run? Check for proper operation of the IAC (if equipped). If a problem is found, repair as Symptom 8 - Go to Step 9 necessary. Fixed Does the engine start and continue to run? Symptoms Section 4 - 7

Hard Start Symptoms cont’d

Step Action Value(s) Yes No Check the engine for the following mechanical problems: • Low compression. • Leaking cylinder head gaskets. Symptom 9 • Proper valve set up. - Go to Step 10 Fixed Refer to Intek V-Twin Cylinder OHV repair Manual Section for test procedures. If a problem is found, repair as necessary. Does the engine still have low power output? 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and no malfunctions have been found, review/ inspect the following: Symptom Contact Engine 10 • Visual inspection. - Fixed Manufacturer • Scan tool data/ Code reader data • All electrical connections within a suspected circuit and/or system. If a problem is found, repair as necessary. Does the engine start and continue to run? Section 4- 8 Symptoms

Engine Has Low Power Output

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD 1 - Go to Step 2 tem checked? System Check Was the visual/physical check performed? Go to Visual/ 2 - Go to Step 3 Physical Check Check the following fuel systems for debris, water, or contaminants. • Fuel tanks • Fuel filter Symptom 3 Go to Step 4 • Fuel lines Fixed • Fuel pumps If a problem is found, repair as necessary. Does the engine still have low power output? Check for proper fuel pressure. Refer to section 2 for the test procedure. If a problem is 35-43 Symptom 4 Go to Step 5 found, repair as necessary. PSI Fixed Does the engine start and continue to run? Verify the crankcase oil is at the correct level. Symptom 5 If a problem is found, repair as necessary. - Go to Step 5 Fixed Does the engine still have low power output? Verify that the air filter doesn’t need replaced. Symptom 6 If a problem is found, repair as necessary. - Go to Step 6 Fixed Does the engine still have low power output? Verify the engine doesn’t have a greater engine load on it than is intended for it’s application? Check for the following; • Damaged drive belt. Symptom 7 - Go to Step 7 • For mowers verify the blades are not re- Fixed stricted by debris. • Faulty pulley bearing(s). Does the engine still have low power output? Check the spark plugs for the following conditions. • Verify they are gapped properly. Symptom 8 • Verify they are not gas fouled. -- Go to Step 8 Fixed • Verify they are not excessively worn. If a problem is found, repair as necessary. Does the engine still have low power output? Verify the exhaust is not restricted. If a prob- Symptom 9 lem is found, repair as necessary. - Go to Step 9 Fixed Does the engine still have low power output? Symptoms Section 4 - 9

Engine Has Low Power Output cont’d

Step Action Value(s) Yes No Check the engine for the following mechanical problems: • Low compression. • Leaking cylinder head gaskets. Go to Step Symptom 10 • Proper valve set up. - 10 Fixed Refer to Intek V-Twin Cylinder OHV repair Manual Section for test procedures. If a problem is found, repair as necessary. Does the engine still have low power output? 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and no malfunctions have been found, review/ Contact inspect the following: Engine Symptom 11 • Visual inspection. - Manufac- Fixed • Scan tool data/Code reader data turer • All electrical connections within a suspected circuit and/or system. If a problem is found, repair as necessary. Does the engine still have low power output? Section 4- 10 Symptoms

Engine Hunting and Surging

Step Action Value(s) Yes No Was the “On-Board Diagnostic” (OBD) Sys- Go to OBD 1 - Go to Step 2 tem checked? System Check Was the visual/physical check performed? Go to Visual/ 2 - Go to Step 3 Physical Check Check the following fuel systems for debris, water, or contaminants. • Fuel tanks • Fuel filter Symptoms 3 - Go to Step 4 • Fuel lines Fixed • Fuel pumps If a problem is found, repair as necessary. Is the engine still hunting and surging? Check for proper fuel pressure. Refer to section 2 for the test procedure. If a problem is 35-43 Symptoms 4 Go to Step 5 found, repair as necessary. PSI Fixed Does the engine start and continue to run? Check the battery for the following conditions. • Loose or corroded terminals 12.2- Symptoms 5 • Verify the battery voltage is within the Go to Step 6 13.5v Fixed specified range. If a problem is found, repair as necessary. Verify the crankcase oil is at the correct level. Symptoms 6 If a problem is found, repair as necessary. - Go to Step 7 Fixed Is the engine still hunting and surging? Verify that the air filter doesn’t need replaced. Symptoms 7 If a problem is found, repair as necessary. - Go to Step 8 Fixed Is the engine still hunting and surging? Verify the governor is set up properly. Refer to Intek V-Twin Cylinder OHV repair Manual Symptoms 8 Section 4. If a problem is found, repair as - Go to Step 9 Fixed necessary. Is the engine still hunting and surging? Inspect the governor link spring for damage or improper installation. If a problem is found, Go to Step Symptoms 9 - repair as necessary. 10 Fixed Is the engine still hunting and surging? Disconnect the governor spring, check for binding or uneven resistance in the governor Go to Step Symptoms 10 arm travel from stop to stop. If a problem is - 11 Fixed found, repair as necessary. Is the engine still hunting and surging? Symptoms Section 4 - 11

Engine Hunting and Surging cont’d

Step Action Value(s) Yes No Inspect the governor spring and controls for damage or improper installation. If a problem Go to Step Symptoms 11 - is found, repair as necessary. 12 Fixed Is the engine still hunting and surging? Replace the governor spring or controls. If a Go to Step Symptoms 12 problem is found, repair as necessary. - 13 Fixed Is the engine still hunting and surging? 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and no malfunctions have been found, review/ Contact inspect the following: Engine Symptoms 13 • Visual inspection. - Manufac- Fixed • Scan tool data/ Code reader data turer • All electrical connections within a suspected circuit and/or system. If a problem is found, repair as necessary. Is the engine still hunting and surging? Section 4- 12 Symptoms

ECM Connector J1

Connector/ Wire Possible Symptom Function Pin Number Color From Faulty Circuit IACAHI J1-1 (Idle Air Control A Hi) If equipped BLU/BRN Rough, Unstable, or Incorrect Idle N/A J1-2 (Not Applicable) - MIL J1-3 (Malfunction Indicator Light) ORG/BLK MIL Inoperative N/A J1-4 (Not Applicable) - N/A J1-5 (Not Applicable) - N/A J1-6 (Not Applicable) - CANLo J1-7 (Used only for Development ECM) GRN No Can Signal CANHi J1-8 (Used only for Development ECM) YEL No Can Signal An open ground or high resistance J1-9 GROUND BLK (Power) ground may cause any or all symptoms ESTCOILB J1-10 (Engine Spark Timing Coil B) PPL/WHT Rough Idle, Lack of Power, Stalling IACALO J1-11 (Idle Air Control A Lo) If equipped BLU/GRN Rough, Unstable, or Incorrect Idle IACBHI J1-12 (Idle Air Control B Hi) If equipped BLU/GRY Rough, Unstable, or Incorrect Idle IACBLO J1-13 (Idle Air Control B Lo) If equipped BLU/RED Rough, Unstable, or Incorrect Idle ORG/ J1-14 Safety Interrupt No Start WHT N/A J1-15 (Not Applicable) - N/A J1-16 (Not Applicable) - An open B+ circuit or high resistance MPR J1-17 (Main Power Relay) RED in the B+ circuit may cause any or all symptoms N/A J1-18 (Not Applicable) - Symptoms Section 4 - 13

ECM Connector J2

Connector/ Wire Possible Symptom Function Pin Number Color From Faulty Circuit J2-1 ESTCOILA PPL/BLK Rough Idle, Lack of Power, Stalling (Engine Spark Timing Coil A) An open ground or high resistance J2-2 GROUND BLK (Power) ground may cause any or all symptoms. J2-3 SDATA PNK No Serial Data (Serial Data) J2-4 Crank VR Hi BLK/WHT No Start (23X) LT.BLU/ J2-5 INJA Rough Idle, Lack of Power, Stalling (Injector A) BLK LT. BLU/ J2-6 INJB Rough Idle, Lack of Power, Stalling (Injector B) WHT Lack of Power, Surge, Rough Idle, J2-7 HO2HTR GRY/BLK (Oxygen Sensor Heater) If equipped Exhaust Odor J2-8 MAT TAN/BLK Rough Idle (Manifold Air Temperature) J2-9 FPR BLU/YEL No Start (Fuel Pump Relay) Lack of Performance, Stalling, J2-10 5VRTN1 BRN (5 Volt Return 1) Exhaust Odor, Improper Idle Poor Performance, Surge, Poor Fuel J2-11 MAP WHT/RED (Manifold Absolute Pressure) Economy, Exhaust Odor Poor fuel Economy, Surge, Exhaust J2-12 TPS PNK/BLK (Throttle Position Sensor) If equipped Odor GRN/ J2-13 Crank VR Lo No Start (23X) WHT Poor Performance, Exhaust Odor, J2-14 EHT TAN (Engine Head Temperature Sensor) Rough Idle J2-15 IGN RED No Start, MIL Inoperative (Ignition) Lack of Power, Surge, Rough Idle, J2-16 5VREF RED/WHT (5 Volt Reference) Exhaust Odor HO HI WHT/ Lack of Power, Surge, Rough Idle, J2-17 2 (Oxygen Sensor) GRN Exhaust Odor J2-18 VBAT RED No Start (Voltage Battery) Section 4- 14 Symptoms

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ABREVIATIONS FUEL SYSTEM COMPONENTS Common Abbreviations ...... 1-3 Discription of Fuel Supply Components...... 2-3 Wire Color Abbreviations...... 1-4 Electric Fuel Lift Pump Remove, Install, Inspect Barometric Pressure...... 3a-4 and Flow Test ...... 2-9,10 3b-5 Fuel Injectors Clean, Remove, Install, Cautions ...... 1-2 Inspect...... 2-6 Closed Loop Fuel Control...... 2-2 Fuel Rail Assembly Clean, Remove, Install, Crank Postion Sensor...... 3a-32 Inspect...... 2-5 3b-31 Fuel Pump Module Remove, Install, Inspect and Fuel Pressure Test...... 2-11 In-Line Fuel Filter ...... 2-4 DIAGNOSTIC TROUBLE CODE (DTC) Mechanical Diaphram Lift Pump Remove, Install, Diagnostic Trouble Codes DTC’s ...... 1-5 Inspect and Flow Test...... 2-7,8 Reading DTC’s Using Only The Model 490000 Fuel Pump Relay ...... 3a-25 MIL Blink Code...... 1-5 3b-26 Reading Diagnostic Trouble Codes...... 1-6 Model 610000 Fuel Pump Relay...... 3a-27 On-Board Diagnostic (OBD) System Check..... 1-6 3b-28 Using the Tiny Scan Tool to Read DTC’s...... 1-6 Ignition Coils...... 3a-34 PC Diagnostic Software...... 1-6 3b-33 PC Diagnostic Software with Intermittents...... 1-6,7 In-Line Fuel Filter...... 2-4 How Diagnostic Trouble Codes (DTC) are Set. 1-7 Digital Volt Ohmmeter ...... 1-12 INTEMITTENTS Testing for Intermittents and Poor Connections.. 1-11,12

Using PC Diagnostic Software...... 1-6,7 EFI COMPONENT Manifold Absolute Pressure (Map) ...... 3a-4 Model 490000 EFI Component Locator...... 1-16 3b-5 Model 610000 EFI Component Locator...... 1-17 Malfunction Indicator Lamp (Mil)...... 1-5 3a-40 EFI SYSTEM DIAGRAM 3b-39 Model 490000 ...... 3-4, 5, Measuring Voltage...... 1-12 6, 7 Non-Scan Diagnosis Of Operating Concerns Model 610000 ...... 3-8, 9, (No DTC’S Set) ...... 1-7,8 10, 11 On-Board Diagnostic System ...... 1-6 Electrostatic Discharge Damage...... 1-12 On-Board Wiring Harness Service...... 1-13,14 Probing Electrical Connectors ...... 1-11 Back Probing...... 1-11 ENGINE CONTROL MODULE (ECM) Connector Pin Out ...... 3-2,3 SENSORS Connector Pin Out Symptoms...... 4-12,13 Crank Postion Sensor...... 3a-32 ECM Funtions...... 2-3 3b-31 ECM Modes of Operation ...... 2-2 Engine Head Temperature Sensor ...... 3a-10 Closed Loop Fuel Control...... 2-2 3b-11 Verify the ECM is Getting Power...... 3-13 Heated Oxygen Sensor ...... 3a-2,19 Engine Wiring ...... 1-13,14 3b-2,20 Electric Fuel Lift Pump Remove, Install, Idle Air Control...... 3a-36 Inspect and Flow Test ...... 2-9,10 3b-35 Manifold Absolute Pressure...... 3a-4 3b-5 FUEL SYSTEM Manifold Air Temerature...... 3a-7 Fuel Flow Direction 490000...... 2-13 3b-8 Fuel Flow Direction 610000...... 2-14 Throttle Position Sensor...... 2-3,4 Fuel Pressure Relief Proceedure ...... 2-4 3a-13,16 Function of the Fuel Metering System...... 2-2 3b-14,16 Testing Fuel Pressure...... 2-11 Service Precautions...... 1-10 2 Index SYMPTOMS Engine Cranks But Will Not Start...... 4-4,5 Engine Has Low Power Output...... 4-8,9 Engine Hunting and Surging...... 4-10,11 Engine Will Not Crank...... 4-3

SYSTEM VOLTAGE Main Power Relay...... 3a-38 3b-38 Measuring Voltage ...... 1-12 System Voltage...... 3a-38 3b-37 Target Wheel...... 3a-32 3b-31 Testing for Intermittent and Poor Connections . 1-11,12 Test Light...... 1-12 Tiny Scan ...... 1-6 Throttle Body Assembly Clean Remove and Install...... 2-12 Throttle Position Sensor...... 2-3,4 3a-13,16 3b-14,16

TOOLS Special Tool and Equipment...... 1-9 Basic Knowledge and Tools Required...... 1-11 Digital Volt Ohmmeter...... 1-12 Fuel Gauge ...... 1-9 2-4 2-11 Technician Assistant Diagnostic Software...... 1-6 Spark Tester...... 1-9 Tools and Equipment Pictures and Part Numbers 1-9,12 Test Light...... 1-9 Tiny Scan ...... 1-6,9

TROUBLESHOOTING Troubleshooting with a Digital Volt Ohmmeter.. 1-12 Test Probe Notice...... 1-12 Troubleshooting With a Test Light...... 1-12 Troubleshooting Using a Noid Light ...... 1-12 Visual/Physical Inspection...... 1-11,13

VOLTAGE Measuring Voltage...... 1-12

WIRE CONNECTORS Wiring Connector Service...... 1-11 Probing Electrical Connectors ...... 1-11 Back Probing...... 1-11 On-Board Wiring Harness Service ...... 1-13,14 Wire Color Abbreviations ...... 1-4 Wire Splicing...... 1-13,14

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