Circuit Description
The fuel level sensor changes resistance based on the fuel level. The PCM 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 PCM senses a high fuel level sensor signal voltage. When the fuel tank is empty, the fuel level sensor resistance is low and the PCM senses a low fuel level sensor signal voltage. The PCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel percentage in the tank. The PCM sends the fuel level percentage via the fuel level signal circuit to the instrument cluster in order to control the fuel gage. The fuel level information is also used for misfire and EVAP diagnostics.
This diagnostic tests for a stuck fuel level sensor. The PCM sets this DTC when the fuel level sensor signal appears to be stuck based on a lack of signal variation expected during normal operation.