Fuel Gauge

The fuel gauge is an analog device that is located in the instrument cluster. The instrument cluster operates the fuel gauge by the class 2 serial data messages from the PCM/VCM. The fuel gauge indicates the quantity of fuel in the tank when the ignition switch is in the RUN position. When the ignition switch is turned to the OFF, LOCK, START, or ACC position, the pointer may come to rest at any position.

The PCM/VCM receives an input from the fuel level sensor. The fuel level sensor is inside of the fuel tank and has a variable resistor that is controlled by the float in the fuel tank. When the fuel tank is full and the ignition switch is in the RUN position the PCM/VCM should receive a high resistance due to the position of the float inside of the fuel tank. The PCM/VCM interprets this signal and sends a class 2 serial data message to the instrument cluster indicating the percentage of fuel in the tank. The indicator on the fuel gauge then moves to the maximum position or FULL on the gauge face. When the fuel tank is empty the float in the fuel tank is at the lowest position and the resistance is low. The PCM/VCM interprets this signal and sends a class 2 serial data message to the instrument cluster indicating the percentage of fuel in the tank. The indicator on the fuel gauge then moves to the minimum position or EMPTY on the gauge face. Corroded connections or severed ground paths generally cause the indicator to register past FULL on the gauge face. Short circuits to ground generally result in the indicator resting below EMPTY.