BMW X6 Start-Stop Malfunction Causes Random Engine Stalls

Hey there! I had a similar issue with my 2018 BMW X5 last year. The symptoms were exactly what you're describing, start-stop failure followed by unusual engine shutdowns. Turned out my battery was severely degraded and wasn't holding enough charge to support the start-stop system properly. Took it to the garage and they diagnosed it with their BMW-specific diagnostic tool. The battery had dropped below the minimum voltage threshold. They had to replace the battery and reprogram the battery management system. It wasn't just a simple battery swap, the new one needed proper coding to work with the car's systems. This is actually a serious issue since unusual engine shutdowns can be dangerous while driving. After the fix, everything went back to normal and the start-stop has been working perfectly since then. Your symptoms sound identical to what I experienced. I'd suggest getting it checked soon, as continuing to drive with a failing battery can potentially damage other electrical components in the car. Hope this helps!

Thanks for sharing your experience! This sounds exactly like what I'm dealing with. Quick question, do you remember roughly how much you ended up paying for the battery replacement and reprogramming? Also, have you had any other electrical issues pop up since the fix? Just want to know what I might be looking at cost-wise and if I should expect any other related problems down the road.

Hey again! Just to update you, I got my X5 fixed up a few days ago and it cost me 290 € for the whole job. The battery issue was pretty much identical to what you're experiencing, it was totally drained and needed replacing. Really happy to report that the start-stop system is working perfectly now! It's such a relief not having those unusual engine shutoffs anymore. Haven't had a single electrical glitch since the repair, and everything's running just as it should. I'd say you're probably looking at a similar repair bill, give or take a bit. The main thing is getting it sorted quickly, I learned from my mechanic that leaving it too long can cause more expensive problems down the line. But honestly, since getting it fixed, my car's been running like a dream. Just keep in mind they'll need to code the new battery to your car's system, it's not just a straightforward swap. But once it's done properly, you should be good to go! Let me know if you need any other info about my experience with the repair!

Thanks so much for the info! Just got back from my mechanic yesterday actually. You were spot on, it was definitely the battery causing all the trouble. Ended up paying a bit more than you did, around 350€, but they did a full system check while they were at it. Funny story, when I got there, my car decided to die right in their parking lot! Talk about perfect timing. The mechanic had a good laugh about it and said I made it there just in time. They were super professional though, got everything sorted within a few hours. The best part? My start-stop is working perfectly now, and no more unusual shutdowns. Such a relief! They also mentioned I might want to get the alternator checked in about six months just to be safe, but for now, everything's running like clockwork. Really appreciate everyone's help on this. It's such a weight off my mind knowing it wasn't something more serious. Now I can finally enjoy driving again without worrying about getting stranded somewhere!