B Klasse fuel door won't open

Yep, had the same issue on my B Klasse. Seems to be a common electrical fault. First thing I would check is the key fob battery, even though it sounds unrelated. The release mechanism is all electronic, so a weak signal can sometimes cause weird issues. Does the central locking work okay? If the fuel door isn't releasing with the key fob or the button inside, it is probably the same problem I had.

Central locking works fine. Key fob battery is new. So what exactly was the problem and solution in your case? Was it actually the linkage, or something else electrical? Did you diagnose it yourself, or did you take it to a shop?

Didn't diagnose myself. I brought it in. Turned out it was a faulty actuator for the fuel flap release. The whole mechanism needed replacing. Apparently, it is a known weakness. They cleared the error code too. Cost me a bit, but at least it's working properly now. Best to get it checked properly.

Thanks for the info. I'll book it in. The quote I got was around 210€, which seems reasonable considering the issue. Hopefully, it will solve the problem.