Circuit Description

The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level. The sender consists of a variable resistor that changes resistance based on the fuel level in the tank. The ECM/PCM monitors the voltage across the sender resistance in order to determine the fuel level. The ECM/PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel, in percent. The ECM/PCM sends the fuel level percent via the serial data circuit to the instrument cluster in order to control the fuel gage. When the fuel level percent reaches a predetermined low level, the instrument panel cluster (IPC) will illuminate the low fuel indicator.