BMW 5 Key Fob Not Working, Antenna Issue Suspected

Hey there! I've got some experience with cars, and funny enough, I had a similar issue with my 2020 BMW 3 Series diesel last year. My also owns a BMW 7 Series, so I'm quite familiar with these cars. The symptoms you're describing sound exactly like what I dealt with. For me, it turned out to be a faulty connection in the antenna wiring harness. Took it to my regular workshop, and they diagnosed it pretty quickly. They had to fix a damaged cable connection near the front bumper area, total bill came to 95 Euro and solved the problem completely. Before you head to the workshop though, could you share: Have you noticed any other electrical issues? Did this start happening suddenly or gradually? Does the key fob battery have enough charge? This info would help me give you more specific advice based on my experience.

Thanks for your detailed reply! Mine's at 77960 KM and just had its service last month. Yeah, it started quite suddenly, was working fine one evening, and the next morning, nothing. Already tried replacing the key fob battery, but no luck. Haven't noticed any other electrical issues though, everything else seems to be working perfectly fine. Think I'll take it to the workshop then, sounds like it could be something similar to what you experienced with the wiring. Good to know it's likely not something super major, was getting a bit worried there! Thanks for sharing your experience, really helpful!

Hey again! Back to help with more info about your BMW issue. After reading about your mileage and the sudden failure, I'm even more convinced it's similar to what I experienced with my car. Mine was around 65000 KM when it happened, and it was just as sudden, perfectly fine one day, completely dead the next. The fact that you've already tried replacing the key fob battery and had a recent service actually reminds me of my situation too. I initially thought the service might have somehow caused it, but the workshop found that some water had gotten into the wiring connection near the bumper, causing corrosion. These things can happen even with regular maintenance. Given what you're describing, I'd bet good money it's the same antenna wiring issue I had. The repair was pretty straightforward once they identified the problem, took them about 2 hours total. Just make sure they check the entire wiring harness in that area, not just the obvious connection points. My mechanic found that moisture had traveled along the wire a bit, so they had to replace a slightly longer section than initially planned. Keep me posted on what they find, I'm really curious to know if it turns out to be the same issue! These BMWs are great cars, but they can be a bit finicky with their electronics sometimes.

Thanks for all this extra information! You've really helped put my mind at ease about the whole situation. It's reassuring to hear that your repair was relatively straightforward and didn't take too long. Funny how our situations are so similar, right down to the sudden failure! I've actually just booked it in at the workshop for tomorrow morning. They seemed to know exactly what I was talking about when I described the symptoms, which is a good sign. The mechanic mentioned they've seen quite a few similar cases with BMWs, especially around the antenna wiring. I'll definitely get them to check the entire wiring harness like you suggested, that's a really good tip about the moisture potentially traveling along the wire. Better to have them do a thorough job the first time around than have to bring it back again. I'll let you know how it goes once they've had a look at it. Really appreciate all your help and insights, it's great to hear from someone who's been through the same thing!