More detail on how to free a stuck fuel filler flap.
Repair stuck fuel filler flap.
No panel removal.
You could even do it on a garage forecourt, if you had to in an emergency.
I believe the solenoid that allows the flap to be opened can fail, if you need fuel and this happens you are stuffed.
Can be carried out without tools. I used a 300mm piece of plastic rod..
Final shot shows the plunger in the up/unlocked position, it looks a little like the nozzle on a hand wash dispenser.

свернуть