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 7 times.
    • The ABS indicator illuminates briefly.
    • The service engine soon indicator (MIL) illuminates briefly.
    • The charge indicator illuminates briefly.
    • The fuel gauge cycles.
    • The speedometer cycles.
    • All message center segments illuminate briefly.

Indicators and Warning Messages

Refer to Indicator/Warning Message Description and Operation .

Engine Coolant Temperature Gauge

The IPC displays the engine coolant temperature as determined by the PCM. 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 PCM detects a malfunction in the engine coolant temperature sensor circuit.
    • The IPC detects a loss of class 2 communication with the PCM.

Engine Oil Pressure Gauge

The IPC uses the engine oil sensor signal to determine the engine oil pressure. The oil pressure sensor signal circuit is hard-wired to the IPC. The engine oil pressure sensor signal to the IPC is a variable resistance ranging from 0-90 ohms. A sensor resistance of 1 ohms will display as 0 psi (0 kPa) and a resistance of 88 ohms will display as 80 psi (550 kPa). The Check Engine Oil Pressure indicator will be displayed in the message center if the IPC detects a low engine oil pressure.

Fuel Gauge

The IPC displays the fuel level as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the fuel level percent. The fuel gauge defaults to empty if:

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

When the fuel level is less than a pre-determined value, the low fuel indicator illuminates.

Reviewing the fuel system description will further explain how the system functions. Refer to:

    •  Fuel System Description in Engine Controls - 4.3 L
    •  Fuel System Description in Engine Controls - 4.8 L, 5.3 L and 6.0 L
    •  Fuel System Description in Engine Controls - 6.6 L
    •  Fuel System Description in Engine Controls - 8.1 L

Hourmeter

The IPC can display the accumulated engine run time hours using the VF display when the cluster is in the LOCK or ACC position. The IPC stores the accumulated engine run time hours in a non-volatile format. The accumulated hours will not change if the battery was disconnected or removed. When the ignition is OFF and the trip reset switch is pushed in and held for more than 4 seconds, the IPC will display the accumulated hours for 30 seconds. The hourmeter will reset to 0.0 when 10,000 hours are accumulated.

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 displays the vehicle mileage and trip mileage as determined by the IPC. The IPC calculates the mileage based on the vehicle speed signal circuit from the PCM. The odometer will display 'error' if an internal IPC memory failure is detected. The odometer can be configured to display either miles or kilometers.

PRNDL Display

The IPC displays the selected gear position as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the gear position. The PRNDL display blanks if:

    • The PCM detects a malfunction in the transmission range switch circuit.
    • The IPC receives a class 2 message indicating the park position and the column park switch indicates a position other than park (open input).
    • The IPC detects a loss of class 2 communications with the PCM.

Speedometer

The IPC displays the vehicle speed based on the vehicle speed signal from the PCM. The IPC receives the vehicle speed signal via a discreet wire. The IPC uses the vehicle speed signal circuit (4000 pulses/mile) from the PCM in order to calculate the vehicle speed. The speedometer defaults to 0 km/h (0 mph) if a malfunction in the vehicle speed signal circuit (4000 pulses/mile) exists.

Tachometer

The IPC displays the engine speed based on the engine speed signal from the PCM. The IPC receives the engine speed signal from the PCM via a discreet wire. The IPC uses the engine speed signal circuit (2 pulses/engine revolution) from the PCM in order to calculate the engine speed. The tachometer defaults to 0 rpm if a malfunction in the engine speed signal circuit (2 pulses/engine revolution) exists.

Transmission Temperature Gauge

The IPC displays the transmission temperature as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the transmission temperature. The transmission temperature gauge will default to 40°C (100°F) or below if:

    • The PCM detects a malfunction in the transmission temperature sensor circuit.
    • The IPC detects a loss of class 2 communications with the PCM.

Voltmeter

The IPC displays the system voltage as detected at the ignition 1 input of the IPC. When the engine is ON, the gauge should be between 10 and 16 volts.