Circuit Description

The fuel level sensor changes resistance based on fuel level. The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the fuel level sensor in order to determine fuel level. When the fuel tank is full, the sensor resistance is low and the ECM/PCM senses a low signal voltage. When the fuel tank is empty, the sensor resistance is high and the ECM/PCM senses a high signal voltage. The ECM/PCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel (percent) in the tank. The ECM/PCM sends the fuel level percent via the serial data circuit to the instrument panel cluster (IPC) in order to control the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.