P04BFFuel Fill Door Unlock Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- On plug-in hybrids with a sealed, pressurised tank, pressing the fuel button (open request) starts a refuelling mode: the module opens the tank valve, releases the pressure into the charcoal canister and only then unlocks the filler door via an electric actuator (Ford patent). P04BF concerns the unlock circuit: the module detects an open circuit in the output to the door actuator or its relay, which CARB requires for outputs. Mitsubishi's Outlander PHEV from 2023 switches the door opener relay from the engine module and sets P04BF in refuelling mode if the door sensor still reports closed 1 s after actuation. Mitsubishi shows a 'refuelling system service required' message for these codes and gives no drive-cycle pattern.
- What you may notice
- Filler door does not open or lock as commanded
- Refuelling system message in the instrument cluster
- Possibly check engine light
- Likely causes
- LikelyOpen control wire or connector at the door actuator
- PossibleActuator motor or solenoid open internally
- PossibleActuator supply, fuse or relay not working
- RareDriver in the module
- 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 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.