What it means
On vehicles with a motorised fuel fill door (no manual lever) the actuator and position switch report that the door is mechanically stuck open. The motor cannot retract it, typically due to a frozen or dirty hinge, broken cable, or jammed actuator.
How it works
On vehicles with a motorised fuel-fill door, an actuator moves the door and a position switch reports whether it has opened or closed. The control module compares the requested movement with the reported position. P04B5 sets when the door remains open and does not retract as commanded.
Common causes
Most likely first.
- Hinge jammed by ice, dirt or debris
- Actuator linkage or motor broken
- Carbon or debris buildup preventing free movement
Symptoms
- Fuel fill door may remain open or fail to latch
- Fuel door warning may appear, if equipped
- Fuel door may rattle while driving
- Check engine light may come on
How to diagnose it
- Check scan-tool fuel-door status and any stored freeze-frame data to confirm the door was reported open after a close command.
- Inspect the door hinge and surrounding area for ice, dirt, or debris that could hold the door open.
- Check whether the door moves freely by hand only as permitted by the owner's manual, and look for a jammed latch or damaged linkage.
- Inspect the actuator connector and wiring for loose connections or visible damage.
- Command the actuator with a scan tool, if supported, and check its movement and position-switch response against the manufacturer's specification.
Common fixes
- Clear ice or debris from the hinge and latch, then check that the door closes freely.
- Repair or reconnect damaged actuator wiring or connectors.
- Repair or replace a broken actuator linkage or motor.
- Replace a failed position switch if the door moves but its reported state does not change.
Can I keep driving?
Driving is generally possible, but an open door can rattle or be damaged by road debris. Secure it only in a way allowed by the owner's manual and have it repaired if it will not stay closed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.