BMW X4 Key System Failure: Hall Sensor Alert

Hey there! I had a similar issue with my 2020 BMW X3 last month. The key symbol showed up and the car wouldn't start, turned out to be more than just the Hall sensor. The control unit was actually defective and needed replacement. Had it fixed at the dealership since it was a complex electrical issue. The whole repair took about 2 days because they had to program the new control unit and sync it with the key. It was quite serious because without a working control unit, the car's security system basically locks everything down. Just a heads up, don't try any DIY fixes on this one. The immobilizer system is pretty sophisticated and needs proper diagnostic equipment to sort out. If your symptoms match mine, you're probably looking at a control unit replacement too. Hope this helps with your decision.

Thanks for sharing your experience! That definitely sounds like what I'm dealing with. I'm relieved to hear it got sorted out, even if it was more complex than initially thought. Would you mind sharing how much the repair set you back? Also curious if you've had any issues since the control unit was replaced? Been debating whether to go straight to the dealer or try my regular shop first, so your insight really helps.

Hey again! Happy to update you! After seeing your symptoms, I can definitely confirm it was the same issue. Got it all sorted at the dealership and haven't had a single problem since. The Hall sensor in the ignition key was indeed defective, and they fixed that along with replacing the control unit. Total bill came to 1000 €, not cheap, but worth every penny for the peace of mind. Since the repair three weeks ago, my X3 starts perfectly every time, no more warning lights or key symbols on the dash. Trust me, going to the dealer was the right call for this one. My regular mechanic actually admitted these sophisticated electronic issues are better handled by the dealer's diagnostic equipment. If you're seeing the same symptoms, I'd skip the regular shop and head straight to the dealer. You'll save time and possibly money in the long run by avoiding multiple diagnostic attempts. Just make sure they thoroughly check both the key and the control unit. Let me know how it works out for you!

Thanks for the detailed follow-up! Just got back from getting my car fixed and thought I'd share my experience. You were spot on about going to the dealer! Initially took it to my regular mechanic who spent hours trying to diagnose it. They couldn't figure it out and charged me for the diagnostic time. Should've listened to your advice right away! Finally took it to the dealer, and they immediately knew what was wrong. The whole thing set me back about 950 €, pretty close to what you paid. They replaced both the Hall sensor and control unit, plus reprogrammed everything. Took them about a day and a half to complete the work. Car's running perfectly now, starts right up every time, no warning lights. Really appreciate your help on this one. You saved me from wasting more time at my regular shop. Definitely learned my lesson about dealing with these complex electronic issues!