Circuit Description

The fuel level sensor is mounted in the fuel level sensor unit. The sensor detects fuel level in fuel tank and transmits a signal to the ECM. It consists of 2 parts. One is the mechanical float and the other is a variable resistor. Fuel level sensor output voltage changes depending on movement of the fuel mechanical float.

When vehicle is parked, naturally fuel level in the fuel tank is stable. It means that output signal of the fuel level sensor does not change. If ECM senses sloshing signal from the sensor, fuel level sensor malfunction is detected. Malfunction is detected when, even though vehicle is parked, a signal being varied is sent from the fuel level sensor to ECM.