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 will illuminate briefly at key up:

Refer to Indicator/Warning Message Description and Operation .

The engine coolant temperature (ECT) is displayed in the IPC, based on information from the ECT sensor. The ECT sensor signal circuit is hard-wired to the IPC. An ECT sensor resistance of approximately 1305 ohms will display an ECT gage temperature of approximately 40°C (104°F). An ECT sensor resistance of approximately 61.9 ohms will display an ECT gage temperature of approximately 118°C (245°F). The check gages indicator illuminates in the IPC, when the engine coolant temperature is at or above 118°C (245°F).

The engine oil pressure (EOP) is displayed in the IPC, based on information from the EOP sensor. An EOP sensor resistance of 1 ohms will display as approximately 0 psi (0 kPa). An EOP sensor resistance of 88 ohms will display as approximately 80 psi (550 kPa). The check gages indicator illuminates in the IPC, when the oil pressure is at or below 34 kPa (5 psi).

SINGLE TANK (8.1L)

The fuel level is displayed in the IPC, based on the information from the fuel level sensor signal circuit. The fuel level sensor changes resistance (40-250 ohms) based on the fuel level. When the fuel tank is full the fuel level sensor resistance is high. When the fuel tank is empty the fuel level sensor resistance is low. The PCM monitors the signal circuit of the fuel level sensor in order to determine the fuel level. The PCM calculates the total remaining fuel percentage in the fuel tank based on the fuel level sensor resistance and the PCM 5 volt reference. The IPC receives the total amount of fuel remaining information from the PCM via the fuel level sensor signal circuit.

DUAL TANK (8.1L)

The fuel balance pump module monitors the signal circuit of the fuel level sensors in order to determine the fuel level. When the fuel tanks are full, the fuel level sensors resistance is high. When the fuel tanks are empty the fuel level sensors resistance is low. The fuel balance pump module averages the resistance of the primary and the secondary fuel level sensors in order to produce an equal resistance value that reflects the average level of both tanks. The fuel balance pump module equalizes the fuel levels in both tanks while supplying fuel to the engine from the primary tank. The PCM monitors the fuel level signal from the fuel balance pump module in order to determine the fuel level. The PCM calculates the total amount of remaining fuel based on the information from the fuel balance pump module. The IPC receives the total amount of fuel remaining information from the PCM via the fuel level sensor signal circuit. The fuel level sensor changes resistance (40-250 ohms) based on the fuel level.

SINGLE TANK (6.5L)

The fuel level is displayed in the IPC, based on the information from the fuel level sensor signal circuit. The fuel level sensor signal is a variable resistance (0-90 ohms) based on the fuel level. When the fuel tank is full the fuel level sensor resistance is high. When the fuel tank is empty the fuel level sensor resistance is low.

DUAL TANK (6.5L)

The fuel balance pump module monitors the signal circuit of the fuel level sensor in order to determine the fuel level. When the fuel tank is full the fuel level sensor resistance is high. When the fuel tank is empty the fuel level sensor resistance is low. The fuel balance pump module calculates the total remaining fuel percentage in the fuel tank based on the fuel level sensor resistance and the fuel balance pump module 5 volt reference. The fuel balance pump module averages the resistance of the primary and the secondary fuel level sensors in order to produce an equal resistance value that reflects the average level of both fuel tanks. The fuel balance pump module equalizes the fuel levels in both tanks while supplying fuel to the engine from the primary fuel tank. The IPC receives total amount of fuel remaining information from the fuel balance pump module via the fuel level sensor signal circuit.

The IPC contains a season odometer and a trip odometer. Briefly 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 PCM. The mileage is displayed in the IPC, based on the vehicle speed information from the PCM. The odometer displays either kilometers or miles.

The vehicle speed is displayed in the IPC, based on the information from the PCM. The PCM monitors the vehicle speed sensor signal circuit in order to convert the data received from the vehicle speed sensor into a 4000 pulses/mile signal. The PCM uses the vehicle speed signal circuit in order to display the vehicle speed in the IPC. If the PCM detects a malfunction in the vehicle speed signal circuit, the speedometer will default to 0 km/h (0 mph). The speedometer displays km/h and mph.

The vehicle speed is displayed in the IPC, based on the information from the VSS buffer. The VSS buffer monitors the vehicle speed sensor signal circuit in order to convert the data received from the vehicle speed sensor into a 4000 pulses/mile signal. The VSS buffer uses the vehicle speed signal circuit in order to display the vehicle speed in the IPC. When a malfunction exists in the vehicle speed signal circuit, the speedometer will default to 0 km/h (0 mph). The speedometer displays km/h and mph.

The PCM (8.1L) converts the data from the crankshaft position sensor into a 2 pulses/engine revolution signal. The PCM uses the engine speed signal circuit in order to display the engine speed in the IPC. The tachometer defaults to 0 RPM if a malfunction in the engine speed signal circuit exists.

The 6.5L engine uses voltage pulses from the generator via the engine speed signal circuit to determine the engine speed. Solid state circuits convert the pulse frequency in order to move the pointer of the tachometer.

The system voltage is displayed in the IPC, based on the voltage detected at the ignition 1 input of the IPC. The voltmeter measures the electrical system voltage when the ignition switch is in the RUN or START position.