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 for 5 seconds:

    • The antilock brake system (ABS) indicator
    • The brake indicator
    • The park brake indicator
    • The security indicator
    • The upshift indicator
    • All gages sweep to their minimum physical position and then to their actual physical position.

The following indicators illuminate for the specified times:

    • The AIR BAG indicator flashes 7 times.
    • The seat belt indicator illuminates for 20 seconds followed by 55 seconds of flashing with the drivers seat belt unfastened or the seat belt indicator will illuminate for 8 seconds with the drivers seat belt fastened.
    • All message center segments illuminate briefly.

Indicators and Warning Messages

Refer to Indicator/Warning Message Description and Operation.

Engine Coolant Temperature Gage

The instrument panel cluster (IPC) displays the engine coolant temperature as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 100°F (40°C) or below if:

    • The ECM detects a malfunction in the engine coolant temperature sensor circuit.
    • The IPC detects a loss of serial data communications with the BCM.
    • The BCM detects a loss of serial data communications with the ECM.

Fuel Gage

The instrument panel cluster (IPC) displays the fuel level as determined by the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the fuel level percent. The fuel gage defaults to empty if:

    • The ECM detects a malfunction in the fuel level sensor circuit.
    • The IPC detects a loss of serial data communications with the BCM.
    • The BCM detects a loss of serial data communications with the ECM.

Odometer

The vehicle odometer is calculated and stored electronically in the body control module (BCM). The instrument panel cluster (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 BCM calculates the mileage based on the vehicle speed signal from the engine control module (ECM). The BCM then sends a serial data message to the IPC indicating the value of the odometer. The odometer will display 'error' if an internal BCM memory failure is detected.

PRND321 Display

The instrument panel cluster (IPC) displays the selected gear position as determined by the engine control module (ECM). The IPC receives a serial data message from the ECM indicating the gear position. The PRND321 display blanks if:

    • The ECM detects a malfunction in the transmission range switch circuit.
    • The IPC detects a loss of serial data communications with the BCM.
    • The BCM detects a loss of serial data communications with the ECM.

Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on the information from the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the vehicle speed.

Tachometer

The instrument panel cluster (IPC) displays the engine speed based on the information from the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the engine speed.

Voltmeter

The instrument panel cluster (IPC) displays the vehicle voltage based on the information from the body control module (BCM). The IPC uses the serial data information from the BCM to provide a voltage level indication on the voltmeter.