P04CDFuel Fill Door Open Request Sensor/Switch Stuck On
- 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). P04CD means the button is detected as pressed for an unusually long time. Mitsubishi's Outlander PHEV from 2023 sets it if the button line stays at 1 V or less for 13.5 minutes – a jammed button or a short to ground. Mitsubishi shows a 'refuelling system service required' message for these codes and gives no drive-cycle pattern.
- What you may notice
- Fuel button has no effect, door does not open
- Refuelling system message in the instrument cluster
- Refuelling only via emergency release
- Likely causes
- LikelyFuel button mechanically jammed or sticking
- PossibleButton line shorted to ground
- PossibleMoisture or dirt in the button
- RareModule
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.