Circuit Description

The fuel level sensor changes resistance in response to the fuel level. The body control module (BCM) 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 and the BCM senses a high signal voltage. When the fuel tank is empty, the fuel level sensor resistance is low and the BCM senses a low signal voltage. The BCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel in the tank. The BCM sends the fuel level percentage via the class 2 serial data circuit to the instrument panel cluster (IPC) in order to control the fuel gage. The PCM receives a class 2 message from the BCM indicating the fuel level percentage. The fuel level information is used for misfire and EVAP diagnostics.

This diagnostic tests for a stuck fuel level sensor signal. The PCM sets this DTC if the fuel level sensor signal appears to be stuck based on a lack of signal variation expected during normal operation.