Circuit Description

The fuel level sender changes resistance based on the fuel level. The ECM monitors the signal circuit of the fuel level sender in order to determine fuel level. When the fuel tank is full, the sender resistance is high and the ECM senses a high signal voltage. When the fuel tank is empty, the sender resistance is low and the ECM senses a low signal voltage. The ECM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel percent in the tank. The ECM sends the fuel level percent via the class 2 serial data circuit to the BCM. The BCM sends that class 2 message to the IPC in order to display the fuel level percent on the fuel gage. The fuel level information is also used for misfire and EVAP diagnostics.

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