OBD-II code · Powertrain (generic)

P04CA Fuel Fill Door Open Request Sensor or Switch Circuit Low

Same as P04C8 with the signal voltage shorted to ground or constantly low. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

Is it safe to drive with P04CA?

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

Common causes

  • Most likelySignal shorted to ground
  • Less likelyConnector pins corroded - high contact resistance
  • Less likelyHarness chafing through insulation

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.