Fuel Level Sensor Diagnosis

Circuit Description
The powertrain control module (PCM) supplies 5 volts to the fuel level sensor circuit. The fuel level sensor varies the voltage relative to the amount of fuel in the tank. The PCM monitors the voltage on the fuel level circuit in order to calculate the amount of fuel in the tank. The PCM sends fuel level information via the Class 2 serial data to the instrument panel fuel gauge

The PCM uses fuel level information in order to enable the enhanced evaporative emission diagnostic.

Diagnostic Aids
Inspect for the following condition:
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, faulty terminal to wire connections and damaged harness.

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
3. This checks for proper PCM voltage, ground and circuit wiring. The PCM supplies 5V to the fuel level sensor.
5. This checks for a fuel level sensor circuit shorted to battery positive.
6. This checks for a faulty fuel level sensor ground or splice connection.