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 occurs at key up:

    • The air bag indicator flashes 8 times.
    • The ABS indicator illuminates briefly.
    • The check engine indicator (MIL) illuminates briefly.
    • The brake indicator illuminates briefly.
    • All gages sweep.
    • The HUD illuminates all segments briefly.
    • The security indicator illuminates briefly.
    • The traction indicator illuminates briefly.
    • The tire inflation monitor indicator illuminates briefly.
    • The seat belt indicator illuminates.
    • The MPH or KM/H indicator illuminates.
    • The audible warning chimes 6 times.

Indicators and Warning Messages

Refer to Indicator/Warning Message Description and Operation.

Engine Coolant Temperature Gage

The IPC displays the engine coolant temperature as determined by the engine control module (ECM). The ECM monitors the engine coolant temperature sensor. The IPC receives a serial data message from the ECM indicating the engine coolant temperature. The engine coolant temperature status message is also displayed in the DIC. The engine coolant temperature gage defaults to the lowest position possible if:

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

Engine Oil Pressure Gage

The IPC displays the engine oil pressure as determined by the ECM. The ECM monitors the engine oil pressure sensor. The IPC receives a serial data message from the ECM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 kPa (0 psi) or below if:

    • The ECM detects a malfunction in the engine oil pressure sensor signal circuit.
    • The IPC detects a loss of serial data communication with the ECM.

Fuel Gage

The IPC displays the fuel level as determined by the ECM. The ECM monitors the fuel level sensor signal. The IPC receives serial data messages from the ECM 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 communication with the ECM.

Speedometer

The IPC displays the vehicle speed based on the information from the vehicle speed sensor. The ECM converts the data from the vehicle speed sensor to a 4,000 pulses/mile signal. The IPC uses the vehicle speed signal circuit (4,000 pulses/mile) from the ECM in order to calculate the vehicle speed. The vehicle speed signal circuit is pulled up to controlled B+ in the IPC. The speedometer defaults to 0 km/h (0 mph) if a malfunction in the vehicle speed signal circuit exists. The speedometer displays either miles or kilometers as requested by the activation of the English/Metric setting on the driver information center (DIC). The associated indicator, MPH or KM/H, illuminates.

Tachometer

The IPC receives a discrete input from the ECM indicating the engine speed. The engine speed signal circuit is pulled up to controlled B+ in the IPC. Each engine revolution represents 2 input pulses to the ECM. The instantaneous engine speed is calculated by the ECM using the time difference between the 2 input pulses. The tachometer will default to 0 RPM if the ECM detects a malfunction in the engine speed signal circuit.

Voltmeter

The vehicle battery voltage is measured by the BCM and sent via the serial data circuit to the IPC. The IPC displays the system voltage in the analog volt gage. The system voltage is also displayed in the DIC in a digital format. When the system voltage is out of range, the IPC displays voltage high or voltage low message in the DIC. The DIC issues the appropriate voltage warning message.