BMW 4 Series Dies at Start, Immobilizer Light Flashing

Hey there! I had a similar issue with my 2012 BMW 3 Series (also had a BMW 5 at the time). I've got some experience working on cars as a hobby mechanic. When my immobilizer acted up, the car kept dying just like yours. Turned out the key needed reprogramming, the communication between the key and the car's computer was messed up. Took it to a specialized workshop and they sorted it out in about an hour. Cost me 45 Euro for the reprogramming. Could you share which engine variant you've got and if you're using the original key or a spare? Also, are you getting any specific error codes? This info would help me give you more specific advice based on my experience. Hope this helps! Let me know if you need more details.

Thanks for the input! My car has been serviced regularly (last service was just 2 months ago at 30616 KM), and I'm using the original key. The error code I'm getting is 2A86, and yes, symptoms match exactly what you described. Did you notice if the problem got worse in certain weather conditions? My car seems particularly unhappy during cold starts. Glad to hear it might just be a reprogramming issue rather than something more serious with the computer system itself.

Hey again! Yes, I absolutely remember having that exact same error code (2A86) on my BMW. And funny you mention the cold starts, that's exactly when my car was at its worst! During winter months, it would sometimes take 3-4 attempts to keep it running. Since I had the key reprogrammed, it's been working like a charm for almost two years now. The fact that you're using the original key is actually good news, that's what I had too. Sometimes duplicate keys can cause more complicated issues. Just a heads up though, when I got mine fixed, the mechanic mentioned that in some cases, if you wait too long, the constant starting/stopping can put extra stress on the starter motor. I was lucky and got it sorted before any additional damage occurred. One thing I didn't mention in my first reply, before taking it to the workshop, I tried cleaning the key fob's contact points with some electronic cleaner. Didn't solve my problem, but might be worth a try if you want to rule out simple fixes first. Keep us posted on how it goes! Always interested to hear how these things work out, especially since we're dealing with the same brand and similar issues.

Thanks so much for the detailed follow-up! That's really helpful to know about the potential starter motor issues, I'll definitely get this sorted soon then. I actually have some electronic cleaner in my garage, so I might try cleaning the key contacts tonight just to see if it helps, though I'm not getting my hopes up too high. I'll call around some specialized workshops tomorrow to get quotes for the reprogramming. The price you mentioned sounds pretty reasonable, especially compared to what I was worrying it might cost! It's such a relief to hear this is likely just a key programming issue rather than a major electronic problem. Thanks again for sharing your experience, it's been super helpful having someone who's been through the exact same thing. I'll make sure to update this thread once I get it fixed in case anyone else runs into similar problems with their BMW in the future.