BMW 8 Dies After Start: Immobilizer Light Warning Signs

I had a similar issue with my 2017 BMW 5 Series 520d last month. The immobilizer system was acting up after a routine service at an unfamiliar garage. Had the same symptoms, flashing immobilizer light, engine cutting out, and trouble starting. Turned out the key programming was corrupted during their diagnostic scan. Had to take it to a specialist who reset the entire immobilizer system and reprogrammed both keys. Wasn't a quick fix, took them about 4 hours to sort everything out. It's actually a serious issue since a faulty immobilizer can completely disable your car. My advice, stay away from shops that aren't familiar with BMW security systems. The immobilizer is linked to multiple control modules and needs proper diagnostic equipment to program correctly. What helped in my case was finding a technician who specializes in BMW security systems. They'll have the right tools and knowledge to properly diagnose and fix these issues without causing additional problems.

Thanks for sharing that, it's really helpful since I'm dealing with almost the exact same thing with my 8. The symptoms match perfectly and it makes sense that it could be related to the key programming after that sketchy service. Just curious, do you remember roughly how much the specialist charged you for the reset and reprogramming work? Also, have you had any issues pop up since they fixed it?

Hey there! Glad to help update you on my BMW 5 Series situation. Since my last post, I can confirm everything's been running perfectly smooth, not a single problem with the immobilizer system after getting it properly sorted. The total bill came to 45€ for the key reprogramming work. Pretty reasonable considering how much stress that flashing immobilizer light was causing! The specialist really knew their stuff and fixed it right the first time. It's such a relief not having to worry about whether the car will start every time I use it. Trust me, once you get a proper BMW specialist to look at it, they'll sort that programming issue right out. Just make sure they've got the right diagnostic equipment for BMW security systems. Let me know how you get on with yours!

Thanks again for all the info! You were absolutely right, I took your advice and found a certified BMW specialist. Got it sorted yesterday and the whole experience was night and day compared to that sketchy mechanic I mentioned earlier. The specialist diagnosed the same issue, corrupted key programming from the previous garage's botched diagnostic scan. They had the proper equipment and fixed it in about 3 hours. Cost me a bit more at 65€, but totally worth it for the peace of mind. Started up perfectly this morning, no more flashing lights or stalling issues. Should've just gone to a proper specialist from the start instead of trying to save a few bucks with that dodgy mechanic. Lesson definitely learned! Really appreciate you sharing your experience, saved me a lot more headache in the long run.