OBD-II code · Powertrain (generic)

P04CD Fuel Fill Door Open Request Sensor or Switch Stuck On

The open-request switch is stuck in the active state - the ECU continuously reads a request to open the fuel fill door. Either the switch is mechanically held closed or the line is shorted to its active level.

Is it safe to drive with P04CD?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelySwitch contact mechanically stuck closed
  • Less likelyCarbon or debris buildup preventing free movement
  • Less likelyComponent wear with age - mechanical play

Repair at a glance

Difficulty
Easy
DIY friendly
Often, with basic tools
Typical labour
0.4–1 h
Emissions test
Usually unaffected
Parts involved
Fuel Fill Door Request Switch

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.