Cluster Description

Certain instrument panel cluster (IPC) features are tested when the ignition is turned on in order to verify the features are working properly. The following occurs at key up:

• The air bag indicator flashes for 7 seconds. • The air brakes indicator illuminates briefly. • The ABS indicator illuminates briefly. • The brake indicator illuminates briefly • The charge indicator illuminates briefly. • The change engine oil indicator illuminates briefly. • The check gauge. indicator illuminates briefly. • The engine overspeed indicator illuminates briefly. • The engine shutdown indicator illuminates briefly. • The fasten seat belt indicator illuminates for about 8 seconds. • The low coolant indicator illuminates briefly. • The low engine oil level indicator illuminates briefly. • The reduced engine power indicator illuminates briefly. • The service engine soon indicator illuminates continuously. • The PRNDL and the odometer segments illuminate.

Indicators and Warning Messages

Engine Coolant Temperature (ECT) Gauge

The IPC displays the engine coolant temperature on the analog engine coolant temperature (ECT) gauge as determined by the powertrain control module (PCM). The PCM monitors the signal circuit of the ECT sensor. When the sensor resistance is high, the engine coolant temperature is low. When the sensor resistance is low, the engine coolant temperature is high. The IPC receives a class 2 message from the PCM indicating the engine coolant temperature. The engine coolant temperature gauge defaults to 75°C (160°F) or below when the following conditions occur: • The PCM detects a malfunction in the engine coolant temperature sensor signal circuit. • The IPC detects a loss of class 2 communications with the PCM.

Engine Oil Pressure (EOP) Gauge

The IPC displays the engine oil pressure on the analog engine oil pressure (EOP) gauge as determined by the PCM. The PCM monitors the signal circuit of the EOP sensor. When the EOP sensor resistance is high, the engine oil pressure is high. When the EOP sensor resistance is low, the engine oil pressure is low. The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The EOP gauge defaults to 0 kPa (0 psi) when the following conditions occur: • The PCM detects a malfunction in the engine oil pressure sensor signal circuit. • The IPC detects a loss of class 2 communication with the PCM.

Fuel Gauge

The IPC displays the fuel level on the analog fuel gauge as determined by the PCM. The PCM monitors the signal circuit of the fuel level sensor. When the fuel level sensor resistance is high, the fuel gauge indicates full. When the fuel level sensor resistance is low, the fuel gauge indicates empty. The IPC receives a class 2 message from the PCM indicating the filtered fuel level percent. The PCM uses 2 filters for the fuel level percent. The slow filter is used during normal operation. The fast filter is used when the engine is just started or when the vehicle is in Park or Neutral. The fast filter allows the fuel gauge to reach the current fuel level quickly. The fuel gauge defaults to empty when the following conditions occur: Hourmeter

The IPC displays the accumulated engine run time hours using the reconfigurable odometer vacuum fluorescent (VF) display. The engine run time hours displays only when the ignition is in the OFF or ACC position and the trip reset switch is pressed for approximately 4 seconds. When the ignition is in the OFF or ACC the IPC displays the engine accumulated hours for up to 30 seconds. The value of the accumulated hours does not change when the battery is disconnected. The hourmeter resets to 0.0 when 10,000 hours are accumulated. The IPC then begins to reaccumulate the engine run time hours from 0.0 hours.

Odometer

The IPC contains a season odometer and a trip odometer. Momentarily press the trip/reset switch on the IPC in order to toggle between the season odometer and the trip odometer. Press the trip/reset switch for greater than 2 seconds, while the trip odometer is displayed, in order to reset the trip odometer. The IPC calculates the mileage for the odometer based on the vehicle speed signal circuit from the PCM. The odometer will display 'error' if an internal IPC memory failure is detected.

PRNDL Display

The IPC displays the selected gear position as determined by the transmission control module (TCM) (LB7, LLY and LG4) or the PCM (L18). The IPC receives a class 2 message indicating the gear position. The PRNDL display blanks if: • The TCM (LB7, LLY and LG4) or the PCM (L18) detects a malfunction in the transmission range switch circuit. • The transmission range displayed does not correspond with the PRNDL class 2 message received by the IPC. • The IPC detects a loss of class 2 communications with the TCM or the PCM.

Speedometer

The IPC displays the vehicle speed on the analog speedometer based on the vehicle speed signal from the PCM. The PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC uses the vehicle speed signal circuit from the PCM in order to calculate the vehicle speed. The IPC also receives a class 2 message from the PCM indicating the vehicle speed. The IPC compares the class 2 value to the vehicle speed signal from the PCM to determine if the vehicle speed is valid. When the IPC detects a malfunction in the vehicle speed signal circuit, the IPC uses the class 2 message from the PCM to indicate the vehicle speed.

Tachometer

The IPC displays the engine speed on the analog tachometer based on the engine speed signal from the PCM. The IPC uses the engine speed signal circuit -- 2 pulses/engine revolution -- from the PCM in order to calculate the engine speed. The IPC also receives a class 2 message from the PCM indicating the engine speed. The IPC compares the class 2 value to the engine speed signal from the PCM to determine if the engine speed is valid. When the IPC detects a malfunction in the engine speed signal circuit, the IPC uses the class 2 message from the PCM to indicate the engine speed.

Transmission Temperature Gauge

The IPC displays the transmission temperature on the analog transmission temperature gauge based on the transmission temperature gauge sensor signal. The IPC monitors the signal circuit of the transmission temperature sensor in order to calculate the transmission temperature. The transmission temperature sensor signal is a variable resistance. At higher temperatures, the transmission temperature sensor has a low resistance. At lower temperatures, the transmission temperature sensor has a high resistance.

Volt Gauge

The IPC displays the system voltage on the analog volt gauge as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the electrical system voltage. The volt gauge defaults to 9 volts when the IPC detects a loss of communications with the PCM. For additional information on the engine electrical system,