GM Service Manual Online
For 1990-2009 cars only

Displays Test

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 indicators illuminate briefly at key up unless otherwise noted:

    • Antilock Brake System (ABS) Indicator
    • Charge Indicator
    • Brake System Indicator
    • Coolant Temperature Indicator
    • Engine Oil Pressure Indicator
    • High Beam Indicator
    • Tire Pressure Low Indicator
    • Turn Signal Indicator
    • Upshift Indicator

Indicators and Warning Messages

Refer to Indicator/Warning Message Description and Operation .

Engine Coolant Temperature Gage

The engine control module (ECM) or the powertrain control module (PCM) monitors the coolant temperature sensor to determine the coolant temperature. The ECM/PCM sends the coolant temperature information to the instrument panel cluster (IPC) via class 2 serial data message for display. The engine coolant temperature gage defaults to 0 or below if:

    • The ECM/PCM detects a system malfuntion.
    • The IPC detects a loss of class 2 communications with the ECM/PCM.

Fuel Gage

The instrument panel cluster (IPC) displays the fuel level as determined by the powertrain control module (PCM)/engine control module (ECM). The IPC receives a class 2 message from the ECM/PCM indicating the fuel level percent. The fuel gage defaults to empty (E) if:

    • The PCM/ECM detects a malfunction in the fuel level sensor circuit.
    • The IPC detects a loss of class 2 communications with the ECM/PCM.

When the fuel level is less than a certain low percentage, LOW FUEL message displays in the driver information center (DIC).

Odometer

The vehicle odometer is calculated and stored electronically in the body control module (BCM) and is sent via class 2 to the instrument panel cluster (IPC) for display. The BCM calculates and stores the mileage based on the vehicle speed class 2 message from the powertrain control module (PCM)/engine control module (ECM). The IPC displays the season odometer information from the BCM in the driver information center (DIC). The odometer will display error if the IPC detects an invalid odometer data from the BCM. After an invalid odometer data is received from the BCM, the IPC will display the last known odometer reading for 1.5 seconds before error is displayed in the DIC.

Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on class 2 serial data message from the powertrain control module (PCM) or the engine control module (ECM). The speedometer will default to 0 km/h (0 mph) if:

    • The PCM/ECM detects a malfunction in the vehicle speed sensor circuit.
    • The IPC detects a loss of class 2 communications with the PCM/ECM.
    • The transmission control module (TCM) detects a loss of GMLAN communications with the TCM.

Tachometer

The instrument panel cluster (IPC) displays the engine speed as determined by the powertrain control module (PCM)/engine control module (ECM). The IPC receives a class 2 message from the ECM/PCM indicating the engine speed. The tachometer will default to 0 RPM if:

    • The PCM/ECM detects a malfunction in the engine speed sensor circuit.
    • The IPC detects a loss of GMLAN communications with the PCM/ECM.

Boost Gage

The boost gage is a measure of the engine manifold air pressure. The powertrain control module (PCM) sends a PWM signal to the boost gage indicating the manifold air pressure. The boost gage displays the engine air intake above and below the ambient pressure. The PCM controls the engine boost pressure with the boost control solenoid. The engine boost system pumps more air than the engine would normally use into the intake manifold. The excess air pumped into the intake manifold, creates the engine boost effect. The maximum boost pressure is about 83 kPa (12 psi).

The boost gage performs a self test by the gage dial moving to 0 kPa (0 psi) when the ignition is turned ON and the boost gage is also turned ON. Refer to Supercharger Description and Operation or Boost Control System Description for the 2.0L engine.

Engine RPM Indicator

The engine RPM indicator are a series of LEDs that are set to illuminate and indicate to the driver when the engine attains a certain engine RPM. The indicators are factory preset to illuminate at certain engine RPM ranges. The total engine RPM range available to set is 8500 RPM and there are only three possible RPM settings available for the transmission range.The factory RPM presets can be changed to any prefered RPM settings but are always available at the push of a button. Pushing the reset button reverts the RPM indicator to the factory presets. The factory presets are the default settings for the engine RPM indicator. The engine RPM indicator uses the engine speed signal circuit from the PCM to determine when the engine has attained a certain engine RPM.

The engine RPM indicator performs a self test by the when the ignition is turned ON. The engine RPM indicator LEDs briefly turns ON and OFF. Refer to Supercharger Description and Operation or Boost Control System Description for the 2.0L engine.