BMW M4 Fuel Door Lockout & System Failures Strike

Hey there! I had a similar issue with my 2016 BMW M3 last year. The fuel flap lock actuator failed, but it turned out the real problem was the central locking control module and damaged linkage. The symptoms were exactly like yours, fuel door wouldn't respond, dashboard lit up like a Christmas tree, and several other electrical functions went haywire. The mechanic found that moisture had gotten into the wiring harness, causing corrosion in the connections. The linkage was also physically damaged from repeated attempts to open the flap when it first started acting up. This was definitely a serious issue since it affected multiple systems. In my case, they had to replace the control module and repair the linkage assembly. These parts are buried pretty deep, so it took some time to fix. If you're experiencing the same symptoms, I'd recommend finding a BMW specialist rather than a general mechanic. The diagnostic equipment needs to be spot on for these electronic issues.

Hey, thanks a lot for sharing your experience! It really helps to know someone went through the same headache. My symptoms do sound exactly like what you described. Would you mind sharing how much you ended up paying for the whole repair? Also curious if you've had any other issues pop up since they fixed it? Really want to make sure I'm prepared for what's coming.

Hey! Happy to help fill you in on the aftermath. Just recently got my M3 back from the mechanic and I'm glad to report everything's working perfectly now. Haven't had a single problem with the fuel flap or any other systems since the repair. The whole thing set me back 210 € for fixing the linkage issue, but honestly, it was worth every penny to have it done right. The mechanic really knew their stuff, they explained that these problems can cascade if left unchecked, so I'm relieved I got it sorted. My central locking and all the electrical bits are back to working like new. One piece of advice though, make sure you find someone who really knows BMWs. Don't make the same mistake I initially did with a general garage. A specialist might cost a bit more upfront, but they'll diagnose and fix it properly the first time. Let me know if you need any other details! Always happy to help another M-series owner out.

Thanks for all that info! I bit the bullet and took it to a BMW specialist yesterday. You were spot on, they found the same issues with the control module and wiring. Cost me a bit more than yours at 280 € but they did a thorough job. Funny story actually, while I was waiting at the shop, another guy came in with the exact same problem! The mechanic said these issues are pretty common in our models. Got to chatting with him and turns out we have the same build year too. They finished up faster than expected and everything's working perfectly now. No more dashboard warnings, and the fuel flap opens smoothly again. Really glad I went with a specialist instead of trying to save money at my usual mechanic. Should've done this from the start! Thanks again for pushing me in the right direction. Really saved me from potentially making the problem worse!