U066FLost Communication With Low Pressure Fuel System Sensor
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The low-pressure side of a direct-injection fuel system runs from the tank pump to the high-pressure pump, and a sensor there lets the controller regulate the lift pump. If that sensor transmits a digital value, for example over SENT, U066F records that its messages have stopped. None of the public manufacturer documents uses the code. GM's 2025 table 25OBDG03A reads its low-side sensor, labelled fuel pressure sensor B, as a 5 V analog input at the engine controller or the pump module and fails P018C below 4 % of reference (64 failed samples in 80, Type B). Ford's 2024 summary flags its low-pressure rail sensor below 0.049 V or above 4.88 V within 8 s. Analog faults of this sensor are P2539 to P2543. Expect a MIL and possibly hard starting or hesitation under load.
- What you may notice
- Check engine light
- Longer cranking or hard starting
- Hesitation or power loss under heavy load
- Likely causes
- LikelySignal, supply or ground wire to the low-pressure sensor damaged
- PossibleConnector at the sensor or fuel line corroded or not latched
- PossibleSensor electronics failed and no longer transmit
- RareReceiving input or software of the engine or pump control module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.