Fuel Gauge

Fuel gauge uses a 3-terminal fuel level sensor. One terminal is tied to ground, one terminal is tied to ignition voltage and third terminal is a sensing line, which is tied to Body Computer Module (BCM). With fuel tank full, fuel tank float moves sensing line voltage close to battery voltage. If fuel tank is near empty, float moves sensing line voltage closer to zero. The BCM turns this analog voltage to a digital voltage. This signal is sent to the Instrument Panel Cluster (IPC) over the serial data line. BCM also compares the voltage at terminal No. 3C11 (ignition "1" input) with fuel level input, so changes in system voltage do not affect the accuracy of the fuel gauge.