Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The fuel level sender changes resistance based on fuel level. The engine control module (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 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 primary fuel level sensor signal. The ECM sets this DTC if the primary fuel level sensor signal appears to be stuck based on a lack of signal variation expected during normal operation.