BMW Key Sensor Failure Leaves Driver Stranded

Hey there! I actually had a similar issue with my 2019 BMW 3 Series diesel last winter. The symptoms were identical, key symbol on dash and car refusing to start. Initially thought it was just a dead key fob battery, but turned out the Hall sensor was shot, just like in your case. Got it fixed at a certified shop. The repair involved replacing the entire ignition switch module since the Hall sensor is integrated into it. It was a serious job that took about 4 hours because they had to reprogram the new control unit to sync with the car's immobilizer system. Your mileage is quite close to what mine was when this happened (I was at around 125,000 km). From what the technician told me, this is a known issue with these models after hitting the 100k mark. The fix has been solid, no issues since then. Just make sure whoever does the work has proper diagnostic equipment for BMWs.

Hey, thanks for sharing your experience! Good to know I'm not alone with this problem. It's really helpful to hear that the repair has been reliable for you. Do you remember roughly what you paid for the whole job? Also, curious if you've had any other electrical gremlins pop up since getting it fixed?

Hey again! Happy to give you an update! Yeah, the repair ended up costing me 1000 €, pretty much what I expected for a BMW control unit replacement. Worth every penny though, because the car's been running like a dream since then. The Hall sensor ignition key problem is completely sorted now. And to answer your question about other electrical issues, nope, absolutely nothing! Really clean sailing since getting it fixed. I think this is one of those "fix it right the first time" situations. The new control unit they installed seems to be much more robust than the original one. I remember being worried like you when it first happened, but honestly, once you get it properly fixed by someone who knows what they're doing with BMWs, you shouldn't have any more trouble with it. The key symbol hasn't flashed up once since the repair, and the car starts perfectly every time. Let me know how it goes with yours!

Thanks so much for the detailed info! I bit the bullet and took it to a certified BMW specialist yesterday. The whole experience was actually way better than I expected. The mechanic was super transparent about everything. Showed me the old unit and explained why it failed. Just like in your case, they had to replace the entire ignition switch module. Cost me about 950 €, pretty close to what you paid. Got the car back today and it's running perfectly. No more key symbol, starts right up every time. Such a relief! Really glad I didn't try to cut corners or go back to that sketchy garage. Sometimes it's worth paying a bit more to get things done right. Thanks again for helping me make the right call on this. It's great when these things work out well!