Fuel Level Sensor "A" Circuit

Possible causes

• CommonWorn sender track - the most common failure on a high-mileage vehicle
• CommonFailed fuel level sender in the tank
• CommonCorroded connector at the tank or under the rear seat
• PossibleDamaged wiring under the vehicle
• PossibleFloat detached or fuel-logged
• PossibleLoss of reference voltage or earth

What you might notice

• Fuel gauge wrong, jumping or stuck
• Range calculation implausible
• Low fuel warning at the wrong level
• Running out of fuel unexpectedly
• EVAP or misfire monitors not completing
• Check engine light on

What to check, in order

1. Watch the reported level while the tank is filled. A reading that jumps or sticks at one point identifies a worn sender track.
2. Inspect the connector, usually reachable under the rear seat or through a boot floor panel.
3. Check the reference voltage and earth at the sender.
4. Note that several self-tests depend on knowing the fuel level - EVAP leak tests will not run on a nearly full or nearly empty tank, and misfire detection is suppressed when the tank is very low. So a fuel level fault stops unrelated monitors completing.
5. Until it is fixed, work by trip mileage rather than by the gauge. Running a tank very low is hard on the fuel pump, which relies on the fuel around it for cooling.