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
    • Battery Indicator
    • Brake System Indicator
    • Coolant Temperature Indicator
    • Engine Oil Pressure Indicator
    • Tire Pressure Low Indicator

Indicators and Warning Messages

Refer to Indicator/Warning Message Description and Operation.

Charge/Assist Gage (Hybrid)

The charge/assist gage displays the level of charging or assist (discharge) of the hybrid battery pack. The charge/assist gage displays the charging and discharge activities on the battery intermediate voltage bus. The gage is made up of two separate zones for charge and assist activities. The charge zone displays electric energy flowing to the hybrid battery pack as a result of regenerative braking activity or the vehicle coasting. The assist zone displays electric energy used to boost the vehicle launch flowing out of the hybrid battery pack. The charge/assist gage displays both the magnitude and direction of energy flow on the intermediate voltage bus. When the gage pointer is set in between the two zones, there is no activity on the bus and this indicates a neutral charge state.

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 body control module (BCM) indicating the fuel level. The fuel gage defaults to empty (E) 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.

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

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 body control module (BCM) indicating the engine coolant temperature. The engine coolant temperature gage defaults to 'C' or its lowest temperature pointer if:

    • The ECM detects a malfunction in the engine coolant temperature sensor circuits.
    • 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) and is sent via the serial data circuit to the instrument panel cluster (IPC) for display. The BCM calculates and stores the mileage based on the vehicle speed serial data message from the engine control module (ECM). The IPC displays the season odometer information from the BCM in the driver information center (DIC).

Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on serial data message from the body control module (BCM). The BCM receives vehicle speed data from the engine control module (ECM) via the serial data circuit. The speedometer will default to 0 km/h (0 mph) if:

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

Tachometer

The instrument panel cluster (IPC) displays the engine speed based on serial data message from the body control module (BCM). The BCM receives engine speed data from the engine control module (ECM) via the serial data circuit. The tachometer will default to 0 RPM if:

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

Tachometer (Hybrid)

The hybrid tachometer is a single gage that displays the engine speed and indicates whether the vehicle is in the AUTO STOP or OFF mode of operation. The AUTO STOP mode indicates that the vehicle is still motion capable and the engine could restart by auto start at any time. OFF mode indicates that either the vehicle is turned OFF or the engine has stalled. The instrument panel cluster (IPC) displays the engine speed as determined by the engine control module (ECM). The engine control module (ECM) calculates the engine speed and sends the engine speed serial data message to the BCM. The BCM sends the engine speed via the serial data circuit to the IPC. The tachometer defaults to 0 RPM if:

    • The ECM detects a malfunction in the engine speed sensor.
    • The BCM detects a loss of serial data communication with the ECM.
    • The IPC detects a loss of serial data communication with the BCM.