THE INS & OUTS OF

European cars provide EUROPEAN plenty in the way of self- diagnostics, once you know how to tap into their systems. Here are some tips to help you pull codes and data with MANAGEMENT the best of ’em. SYSTEMS BY KERRY JONSSON

he exact date may be If you don’t have the factory scan tach will move to a different rpm range open to debate, but it tools for all the European manufac- and the Check Engine light (CEL) will was about 1980 that turers, here are some methods for ex- be either on or off. Any combination of the yuppie movement tracting DTCs with minimal equip- tach reading and CEL operation will began. That’s impor- ment, as well as some of the other yield a specific fault. Step on the tant to European car- functions available to help you diag- pedal again to advance to the next makers because yuppies love to be nose tough driveability problems on code. Ttrendy and chic and, having the mon- European nameplates. The only code I quite don’t under- ey to afford it, as a group they be- stand is a 6000-rpm reading with the came large purchasers of European CEL off. This supposedly means a bad vehicles. And that’s important to you In 1984, Audi started offering self-diag- idle switch. Well, if the switch were no because now that these vehicles have nostic capabilities on its 5000s, turbos, good, how did we get into self-diagnos- been out of dealer care for quite and Coupe GTs. Accessing the system tics in the first place! If there are no some time, they’re starting to require is fairly simple: First, run the engine codes stored, the tach will stay at 7000. more frequent service. over 125°F, and while it’s running be- Also note that if the vehicle has a Hi- It used to be that only specialty low 2000 rpm, close the wide-open tachi control unit, the end-of-code se- shops would handle driveability diag- throttle (WOT) switch with your hand, quence will be the tach stuck at 7000 noses on these cars, and experience and keep the throttle’s idle switch with the CEL off; if it’s a Bosch control and a few quick pin voltage checks closed for 4 seconds. If the engine unit, the first code will repeat. would determine what went wrong. won’t start, just crank it for at least 6 Self-diagnostic procedures came to Of course, as systems became more seconds. The tach will jump to 7000 the fore in 1985 on Audi’s 4000 mod- complicated, some form of self-diag- rpm—not the rpm, just the tach. els, and in ’86 they started using these nostics was needed, and all the manu- Now, while holding all that, step on same self-diagnostic procedures on facturers seem to have gone in their the brake pedal once to start the code their 5000s. Be aware that Audi 4000 own direction. In fact, in some cases, sequence. By the way, you can let go of Quattro models never saw self-diag- individual manufacturers have gone the throttle switches after 4 seconds. nostics. On models other than the off in several different directions! After you step on the brake pedal, the Quattro, a four-digit trouble code can

42 December 1999 be accessed through the CEL by run- In 1988, California required some get codes and cycle outputs. But you ning the engine anywhere below 2000 form of self-diagnostics as well as a can still get codes out of the diagnostic rpm, or cranking the engine for at least Check Engine light to indicate when connectors with the same tool used on 6 seconds while bridging two termi- there was a fault with emissions-related and 90 models. A jumper wire nals. These terminals are located on components. These emissions faults spliced to one side of an LED bulb and 1 the fuel pump relay, which is in the can be recorded in memory. On federal a 330-ohm, ⁄4-watt resistor spliced to fuse/relay panel on the driver’s-side vehicles, these codes will be erased in the other side can be placed between cowl area, under the hood. By bridging the next key cycle. the positive terminal of the left diag- these terminals together with a fuse for Note that Audi 80 and 90 models nostic connector and the control unit’s 4 seconds, the CEL would have one with the 2.0-liter engine have a diag- output terminal, in the right connector. long flash followed by a series of four nostic output connector mounted near To initiate the code sequence, the con- shorter flashes, which make up the the airflow meter. By connecting an trol unit’s output terminal needs to be code. This code will repeat, until the LED bulb wired through a 330-ohm, jumped to ground for 4 seconds. Then 1 fuse is inserted again, for 4 seconds. ⁄4-watt resistor between battery positive just follow the same diagnostic pro- This tells the computer to move on to and the diagnostic connector, you can cedures as in previous years. the next code. watch DTCs blink out. A logic probe On the 200 and 200 Quattro models, The ignition control unit codes will also works fine here. there are three diagnostic connectors. be displayed first. You repeat this pro- To initiate the diagnostic procedure, A white connector was added to the 1 cedure until the CEL flashes at 2 ⁄2-sec- you still have to use the fuse on the right side of both connectors. In the ond intervals (no codes). Then you fol- back of the fuel pump relay and follow top pin of this connector is the control low the same routine to extract fuel in- the same procedures as before, but the unit’s diagnostic output wire, so this is jection system codes, until the light engine need not be running. A code where the ground side end of the LED 1 again flashes at 2 ⁄2-second intervals. 4444 means there are no faults detect- test light goes. The bottom terminal of You may notice that the engine’s rpm ed. After all the codes have been dis- the brown connector is still the wire 1 may increase slightly; this is normal. If played and you get the 2 ⁄2-second flash, you need to tap to ground for 4 seconds the CEL blinks twice, the knock sensor insert the fuse for 10 seconds to clear to initiate code output. adjustment is at its maximum of 7.8° codes from memory. In 1990, the diagnostic connectors retard. If the light flashes three times, Since you can get codes on this sys- on the Audi V8 Quattro were moved to the throttle switch inputs aren’t match- tem with the key off, Audi had to alter the passenger-side footwell area, below ing the MAP sensor readings. These how to get into its output state check. the auxiliary relay panel, and another things must be fixed before you can To do it, insert the fuse before turning yellow diagnostic connector was added continue with self-diagnostics. on the ignition key, then close the full for good measure. For once, California On most cars, self-diagnostic proce- throttle switch. The ECU will spit out a techs got lucky. All you had to do was dures are performed with the ignition code and cycle the output, but it will do jumper the two lower pins of the two key on and the engine off, but in the it in a predetermined sequence. connectors on the left to get codes to cases noted above, you must have the In late ’89, Audi altered its self-diag- flash out from the CEL. On federal ve- engine running. Because this system nostic procedures for federal models, hicles, this may not work. So pull out has no memory and cannot remember as well as the model numbers of their your LED test light again and connect stored codes, always go on a spirited cars. With the early-’89 models, you both leads between the two top termi- test drive before entering self-diagnos- still had to use the fuse in the back of nals of the two outermost connectors tics. Also, trying to enter self-diagnos- the fuel pump relay to access self-diag- (the black connector on the left and the tics with key on/engine off will get you nostics. The codes will either blink out new yellow connector on the right). into an output state check. through the Check Engine light or During this retrieval sequence, the The procedure is the same as pulling through your LED test light connected gear position indicator is codes: Insert a fuse into the relay for 4 to the diagnostic connector near the on. This means you’re in “limp-home” seconds, and a code will be displayed, airflow meter. Those ’89 models with- mode. If the engine isn’t running, you’ll which represents the output being cy- out a CEL have only volatile memory. get a code 2111 (engine speed sensor) cled. By repeating this procedure, you On late-’89 models, Audi began us- because of the lack of a speed signal, can cycle several outputs in a specific ing two diagnostic connectors. They’re which is normal. sequence. Note that on Audi’s Coupe mounted under the driver’s-side Audi changed the location of the GT model, you must insert the fuel footwell area and are black on the left, three diagnostic connectors on 100 and pump fuse to move from one output brown on the right. The black connec- 200 series cars in ’92 to the underhood check to the next as well as close the tor has ignition key-on voltage on the relay panel in the cowl area, on the WOT switch to activate the output. You top terminal and is grounded on the driver’s side. The diagnostic procedure may have a code output, but have noth- bottom terminal. The brown connector stayed the same, though. ing cycled on. Also, the control unit has a wire on the bottom pin. This wire In ’95 Audi made still more changes. may output a code even if the system is is the control unit’s diagnostic output. The 100 and 200 were replaced with not on the car. Normally, a factory scan tool is used to the S-series , which maintained

December 1999 43 EUROPEAN ENGINE MANAGEMENT SYSTEMS the previous diagnostic system. Howev- er, the A-series received OBD II treat- ment. The test connectors are still there for Audi’s proprietary scan tool, but that’s all they’re good for. All other models, meanwhile, lost the ability to give us codes without expensive tools. Generally, self-diagnostics can always be performed while the engine is run- ning, and a spirited test drive is encour- aged, especially with turbo models to check the boost sensor. This is kind of like a Ford KOER test or a Nissan Mode 5 test. A wiggle test also comes in handy to help duplicate the conditions under which a fault was set. Photos: Kerry Jonsson Kerry Photos: Don’t be fooled! This BMW diagnostic connector won’t allow you to pull DTCs BMW unless you have the factory’s special MoDic tester. Simply applying the WOT BMW started using self-diagnostics on switch will get codes to spit out through the Check Engine light. its 1987 vehicles, and their method of doing things is much simpler than Au- Mercedes-Benz control unit to switch into duty cycle di’s. To set things in motion, just per- In 1984, Mercedes-Benz began using a feedback testing. form five full-throttle applications with- form of self-diagnostics on its 190E To clear codes, you must display in 5 seconds and any one of four one- model. This basically involved check- them first, then, after 2 seconds, hold digit codes will blink out on the CEL. ing the feedback signal from the oxy- the push button down for 6 seconds. Because the ECU’s wakeup call is initi- gen sensor to the control unit through You must do this after every code re- ated by the wide-open throttle switch, a diagnostic socket located on the driv- trieved. If you have a federal model that’s obviously the first thing to check if er’s-side inner . A duty cycle me- with this diagnostic plug, you can still you can’t go into self-diagnostics. Note ter, or a scope that indicates duty cycle, get codes even though you don’t have a that M-series cars did not posses this can be plugged into pin 3 of this diag- push button or an LED. Just jumper form of self-diagnostics until ’92, when nostic socket while the engine idles. If pin 3 to ground for 2 to 4 seconds and the M5 had its engine slightly enlarged everything is working correctly, you the CEL should spit out codes. To clear from a 3.5 to a 3.6 DOHC. should get a duty cycle of about 50% the codes, jumper pin 3 to ground for 6 Things stayed pretty much the same with some movement while revving seconds for each code, just like on Cali- until the ’88 735 model, which added the motor. However, if the duty cycle fornia models. four-digit codes along with data stream does not change but stays at a fixed In ’92, on some newer Mercedes information through the use of a factory percentage, that indicates that a fault is models like the 400E, a different diag- MoDic tester. Of course, with more present. Each fault has its own default nostic connector is used that requires codes came more work. In order to acti- percentage between 0% and 100%. All an adapter to connect a duty cycle me- vate the next code, you have to step on other Mercedes models got the same ter for percent testing, but California the throttle for 10 seconds. self-diagnostic system two years later, models still maintain the push button This differs slightly from the ’88 in ’86. and the LED. 750iL. This car has a V12 engine, which In 1989, Mercedes’ California vehi- is treated like two inline 6-cylinders in cles received an additional diagnostic Volvo that BMW uses two separate control connector near the battery. This one has Volvo started using its diagnostic rou- units. These control units have their own a push button in the No. 2 position and tine on 1988 700 series models, and on codes, and getting them to come up is an LED in the No. 4 position to access the 900 series when it came out in ’89. done the same way—with five WOT codes, as required by California law. Volvo may have taken a long time to get applications. The right bank of cylinders With the ignition key on, just push the into the game, but all that planning was will display codes first. (You can tell be- button in for 2 to 4 seconds and watch time well spent because they provided a cause all the codes start with one flash.) the LED blink out a code from 1 self-diagnostic system that’s easy to use To get the left bank of codes, just hit the through 10. Pushing the button again and has grown as more complex sys- gas pedal six times. You’ll know you’ve displays the next code and so on, or the tems have been added. done it right because all these codes will LED will stay lit if no codes are present. Three diagnostic modes are available start with two flashes. To clear codes, If there are no codes in memory, the to help diagnose problems: Mode I al- simply unplug the applicable control LED will flash once. Hitting the button lows you to get codes stored in memory. unit for at least 10 seconds. again for 2 to 4 seconds now allows the Mode II requires you to cycle various

44 December 1999 EUROPEAN ENGINE MANAGEMENT SYSTEMS

to mode III (output state check), you must unplug three injectors to get it to go through the test. Volvo added another feature on ’93 models—a fourth mode. Mode IV is used to individually cycle the outputs by inputting a code. This can be done only with the pigtail in socket No. 2, for testing. After pushing the but- ton four times, the LED will use one long flash to prompt you to input a code. Enter the first number of the three-digit code you’re going to enter by pushing the button that many times. The LED will give you another long flash. Then enter the second number the same way. Finally, enter the third Here’s a nice view of an early-’90s Mercedes diagnostic connector. Look close- number after the third long flash. The ly and you’ll see a push button in the No. 2 position in the connector, and an LED will then repeat the code you just LED at No. 4. You can use these in tandem to access DTCs, as well as perform input and proceed to cycle that output. duty cycle feedback testing. Note that some Mercedes models don’t have this However, you must go into modes I and setup, so you’ll have to provide your own LED for diagnostic purposes. III first, otherwise the ECU thinks it’s communicating with a scan tool. inputs to the ECU and puts out a code off idle, the LED will flash out a code Note that you can change the rate of if the ECU notices a problem. Mode 332. If you activate the WOT switch, mode IV by entering a code 311 for III is an output state check that cycles you’ll get a code 333. Crank the engine normal speed, or 312 for double speed. various outputs. and you’ll get code 331. A/C request, A code 313 will get you into 10X speed, The diagnostic connector is found gear select and a/c compressor are some for scan tool communication. behind the driver’s-side strut tower. It of the other inputs you can check. Oth- has a push button, an LED, a pigtail ers were added later. Volkswagen wire and six sockets, numbered 1-3 on To activate mode III, push the but- Ten years before Volkswagen rere- one side and 5-7 on the other. Since this ton down three times for 1 second each. leased the Beetle, its first self-diag- engine management system has two Now the ECU will cycle the outputs nostic system was just getting started control units—one for the ignition and one at a time. The injectors and idle in California. In 1989, VW eliminated one for fuel injection—codes must be control valve should pulse, while the it, circa TSB No. 89 02. Some ’88s extracted separately. To pull fuel injec- purge solenoid and cold start valve have their self-diagnostics disabled. tion codes, put the pigtail into socket should click. Most of these outputs will These ECUs will have a yellow sticker No. 2 and turn the ignition on. Then cycle between 3 and 10 seconds, de- on them. On vehicles built before Jan- push the button on the connector down pending on the year and model of the uary ’89, you can get codes out of a for 1 second. The LED will start to vehicle. Digifant I-equipped California vehi- blink out a three-digit code. If you hit To get ignition system codes, follow cle if the Check Engine light is on. the button one more time, it will blink the same procedures, but this time plug Getting codes is a fairly straightfor- out the next code, if there is one, or re- the pigtail into socket No. 6. In mode I ward procedure: With the ignition on, peat the first code. you’ll get codes, in mode II you’ll test depress the Check switch on the dash That’s all it takes to get codes. To the throttle switch and crank sensor in- for 4 seconds and the CEL will flash clear them, push the button down for 5 puts and in mode III you’ll cycle the out a four-digit code. To display the seconds and, when the LED lights, EGR controller. next fault code, repeat the previous hold it for another 5 seconds. After this, In ’92, Volvo introduced the 800 se- step. Repeat this procedure until the 1 you should get only a 111, which signi- ries, and while the same basic proce- CEL flashes on and off for 2 ⁄2 seconds fies that no problems are present. dures were followed, some subtle each time, just like on an Audi. If no To get into mode II, put the pigtail changes were made to the system. problems are found, you’ll get a code into socket No. 2, turn the ignition on First, there were now two diagnostic 4444. To clear codes you must discon- and push the button twice for 1 second connectors (A and B) mounted behind nect the CTS, hold the Check switch each time. Now you’re into the input the driver’s-side headlight. Use connec- down, turn on the ignition for 5 sec- state check, and the LED will start to tor A, sockets Nos. 2 and 6 for fuel in- onds, then turn it off. flash quickly. When you step on the ac- jection and ignition system self-diag- On CIS-equipped Volkswagens, celerator and the throttle switch comes nostics. On ’93 models, when going in- you can get codes out of the knock

46 December 1999 sensor control unit, as well. Just pull out your LED jumper or logic probe and connect it between the diagnostic test pin in the harness going to the distributor and the positive battery terminal. The LED should light if the control unit is powered up. Next, start the engine and accelerate over 3000 rpm. The LED should go out. If it doesn’t, there’s a fault. Tap the same diagnostic lead you’re using to ground for 3 seconds and one of seven four-digit codes will blink. To get the next code, repeat the previous step. Note that the memory will be erased every time you turn off the ignition. You may find Audi-style diagnostic Here’s the typical diagnostic setup you’ll see when you open the hood of a connectors under the dash on ’89 Volvo 850. Notice there are two different connectors. The black one on the left model Volkswagens. You can use (arrow) allows you to access codes and perform certain input and output them to pull codes just like on a late- checks of the fuel injection and ignition systems. The white one on the right ’89 Audi model, except they are black was added as more systems with self-diagnostics became available. and white, not black and brown. Be aware that the and ground ter- 4444, for no faults. After repairs have then flash out. Keep plugging in the minals may be switched on the black been made, you’ll have to reset the connector for 4 seconds to cycle plug, so check polarity before at- adaptive strategy of the ECU. To do it, through all the outputs, then step on tempting anything. Also, this is not a disconnect and block the crankcase the throttle to activate them individual- factory-recommended procedure, and vent hose, then start the engine. Next, ly. Note that if you exit in the middle of I did not always get the code I set unplug the CTS and leave the connec- this sequence, the computer will re- during testing. Sometimes I got no re- tor off for 1 minute. Then reconnect it, member, and pick up at that same sponse. This also applies to 1990 and but only if the cooling is off. You point when you go back in. After later Corrado models, where the diag- can now shut down the engine and put pulling codes and checking the outputs, nostic connector is located under the the vent hose back on. To finish things you can now go in and clear all applica- shift boot. In these cases, use only the up, clear the CTS code you just set. ble DTCs. After you get to the end of black and white plug, not the blue. On ’92 Volkswagen Corrados, the the code sequence, the CEL should 1 On 1990 Jettas, Golf GTIs, Foxs two diagnostic connectors are right un- flash for 2 ⁄2-second intervals. At this and Passats, you can pull codes using der the heater controls, either behind point, just install the jumper for 4 sec- the black, white and blue diagnostic some blockout caps or under the shift onds and the codes are cleared. connectors. One end of your LED test boot. Once again, you can use a jumper Things changed slightly in ’94, when light goes to the top of the black con- wire on the bottom two pins for 4 sec- Volkswagen switched to one diagnostic nector, the other goes to the top of the onds to pull codes. The CEL will flash connector—in the center console under blue connector. To start the code out- on, confirming that things are working. the heater controls. All models were al- put sequence, jumper the bottom ter- You’ll also get codes 2111 and 2113 (for so provided with an OBD I connector minal of the black plug to the bottom the cam and crank sensors) if the en- plug to do the jumping. Of course, you pin of the white plug for 4 seconds. gine is not running. If it is running, you can still use a jumper wire between pins Repeat this to get more codes, until must keep engine rpm below 1300. 4 (ground) and 15 (ECU output) and go 1 you get a consistent 2 ⁄2-second on/off Self-diagnostics were made available through the same diagnostic procedure flash, indicating no more codes. on all other Volkswagen models in as you would on any Volkswagen. And By 1991, Volkswagen included its 1992, and they include an output state that’s that—until OBD II changed the own jumper assembly under the carpet check, like Audi’s. You can cycle several rules of the game forever! in the trunk or in the glove box, to different outputs, but only in one se- jumper between the black and white quence. To perform the function, con- For a free copy of this connectors. Follow the same proce- nect the jumper, turn the ignition on article, write to: Fulfillment Dept., dures as outlined above. To erase and after 5 seconds, unplug the jumper. MOTOR Magazine, 5600 Crooks codes, connect the jumper provided, Then step on the accelerator to turn on Rd., Troy, MI 48098. Additional copies are $2 each. Send check then turn the ignition on and remove it the component. A code pertaining to 1 or money order. after 2 ⁄2 seconds. You should get a code the component being activated will

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