MKrause86
BMW Key Sensor Failure Leaves 8-Series Stranded
Summary of the thread
A 2023 BMW 8-Series was stranded due to a key sensor failure, indicated by a key symbol on the dashboard. The initial diagnostic suggested a faulty Hall sensor in the ignition key. A similar issue in another BMW model was resolved by replacing and reprogramming the control unit, highlighting the complexity of the car's security system. Ultimately, the problem was traced to a damaged internal circuit in the key, which was repaired by replacing the circuit board and reprogramming the key, restoring the car's functionality.
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4 comment(s)
MKrause86 (community.author)
Thanks for sharing your experience with the control unit issue! Really useful to know it wasn't just the Hall sensor. Would you mind telling me roughly how much you ended up paying for the whole repair? Also curious if you've had any similar problems since they fixed it? I'm trying to budget for this repair and want to make sure I'm prepared for any potential follow-up issues. My BMW's been super reliable until now, so this has caught me off guard a bit.
GWeber21
Hey again! Happy to give you an update! After getting it fixed at the specialist, I can confirm it cost me 1000 € for the control unit replacement and programming. The Hall sensor in the ignition key was definitely the culprit, just like they initially suspected. I've got great news though, haven't had a single problem since the repair, which was about six weeks ago now. The car starts perfectly every time, no more annoying key symbol on the dash, and everything's working exactly as it should. It's such a relief! While the cost might seem steep, it was worth every penny to have it done properly. These modern BMWs are pretty complex machines, and when it comes to their security systems, you really want someone who knows what they're doing. Trust me, once you get it sorted, you'll be back to enjoying that reliable BMW experience you're used to. Let me know how it goes with yours!
MKrause86 (community.author)
Thanks for the detailed follow-up! Just wanted to share that I finally got my car fixed today. Turned out my problem was a bit different, the key's internal circuit was damaged, probably from that time I accidentally dropped it. The mechanic I found was really upfront about everything. He replaced the circuit board and reprogrammed the key, which came to around 600 €. The whole thing took about three hours, but honestly, it was worth the wait. No more frustrating mornings trying to start the car! The mechanic even checked the entire security system while he was at it, just to make sure there weren't any other issues lurking around. Really glad I asked here first, helped me avoid paying for unnecessary repairs and found someone who knew exactly what they were doing. The car's running perfectly now, starts first time, every time. Thanks again for your help!
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BMW
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8
GWeber21
Hey there! Had a similar issue with my 2020 BMW 5 Series last month. The key symbol and starting problems are pretty familiar. In my case, the diagnostic also pointed to the Hall sensor, but it turned out to be a more complex problem with the control unit that manages key recognition. The repair involved replacing the control unit and reprogramming the system. It wasn't just a quick fix, had to leave the car at the garage for two days. Definitely a serious issue since it's related to the car's security system, but totally fixable. The new control unit needed programming to match the car's existing keys. My advice? Skip the general repair shops and head straight to a certified BMW specialist. They'll have the right diagnostic tools and programming equipment to sort this out properly. Trying to save money on this kind of electronic issue usually leads to more headaches later. Best of luck with yours.