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Instrument Cluster / Carrier: Description and Operation



Instrument Cluster Description and Operation

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 3 seconds:

* The Antilock Brake System (ABS) indicator
* The brake indicator
* The CHECK GAGES indicator
* The LOW FUEL indicator
* The park brake indicator
* The OVERSPEED indicator
* The REDUCED POWER indicator
* The SECURITY indicator
* The TAILGATE AJAR 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 battery indicator stays illuminated with ignition on and engine off.
* The seatbelt indicator illuminates for 20 seconds followed by 55 seconds of flashing with the drivers seatbelt unfastened, or, the seatbelt indicator will illuminate for 8 seconds with the drivers seatbelt fastened.
* The SERVICE ENGINE SOON indicator (MIL) illuminates briefly.
* 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 powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the engine coolant temperature. The engine coolant temperature gage defaults to 100°F (40°C) or below if:

* The PCM detects a malfunction in the engine coolant temperature sensor circuit.
* The IPC detects a loss of class 2 communications with the PCM.

Engine Oil Pressure Gage

The instrument panel cluster (IPC) displays the engine oil pressure as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the engine oil pressure. The engine oil pressure gage defaults to 0 psi (0 kPa) or below if:

* The PCM detects a malfunction in the engine oil pressure sensor circuit.
* The IPC detects a loss of class 2 communications with the PCM.

For the 4.2L LL8, the PCM uses an engine oil switch that is open when the oil pressure is normal and closed when the oil pressure is low. At normal pressure, the engine oil pressure gage will display 275 kPa (40 psi). At low pressure, the gage will go to 0 kPa and the low pressure warning will be displayed in the driver information center (DIC). At high pressure, the gage will display 551 kPa (80 psi). Any values between these three values are calculated values determined by the PCM.

Fuel Gage

The instrument panel cluster (IPC) displays the fuel level as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the fuel level percent. The fuel gage 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 IPC illuminates the low fuel indicator.

Odometer

The vehicle odometer is calculated and stored electronically in the instrument panel cluster (IPC). The base IPC contains a season odometer and a trip odometer. The uplevel IPC contains a season odometer and two trip odometers. 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 calculates the mileage based on the vehicle speed signal circuit from the powertrain control module (PCM). The odometer will display 'error' if an internal IPC memory failure is detected. The odometer displays either miles or kilometers as requested by the activation of the Personalization button on the steering wheel controls.

PRND321 Display

The instrument panel cluster (IPC) displays the selected gear position as determined by the powertrain control module (PCM). The IPC receives a class 2 message from the PCM indicating the gear position. The PRND321 display blanks if:

* The PCM detects a malfunction in the transmission range switch circuit.
* The IPC detects a loss of class 2 communications with the PCM.

Speedometer

The instrument panel cluster (IPC) displays the vehicle speed based on the information from the powertrain control module (PCM). The PCM converts the data from the vehicle speed sensor to a 4000 pulses/mile signal. The IPC uses the vehicle speed signal circuit (4000 pulses/mile) from the PCM in order to calculate the vehicle speed. If the IPC detects a malfunction in the vehicle speed signal circuit, the IPC uses the class 2 message from the PCM indicating the vehicle speed.

Tachometer

The instrument panel cluster (IPC) displays the engine speed based on the information from the powertrain control module (PCM). The PCM converts the data from the engine speed sensor to a 2 pulses/engine revolution signal. The IPC uses the engine speed signal circuit (2 pulses/engine revolution) from the PCM in order to calculate the engine speed. If the IPC detects a malfunction in the engine speed signal circuit, the IPC uses the class 2 message from the PCM 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 class 2 serial data information from the BCM to provide a voltage level indication on the voltmeter.

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