BMW 8 Electrical Chaos: FlexRay Bus System Crisis

Hey there! I had a similar issue with my 2021 BMW 7 Series diesel last year. I've got some experience working on cars, nothing too fancy but I know my way around the basics. Had almost identical symptoms, electrical system going crazy, no sound, and error messages popping up everywhere. Took it to my trusted workshop and turned out it was just a faulty connection in one of the main communication cables. They had to run diagnostics to pinpoint the exact location, but the fix was pretty straightforward. Cost me 95 Euro for the repair. The BMW X7 from the same year had similar issues reported, so it might be a common thing with that generation's electrical system. Could you share what specific error codes you're getting? Also, when did these issues start appearing, was it sudden or gradual? This info would help me give you more specific advice based on my experience.

Thanks for the detailed response! Yeah, mine just started acting up last week out of nowhere. I'm at 101228 KM and had my last service about 2 months ago. Getting error codes U0100 and U0101 consistently. Did your mechanic mention anything about checking the ground connections? Just wondering if I should start there before taking it to the dealer since it's still under warranty. The weird part is everything was fine after the service, and then boom, total electrical chaos.

Hey again! Thanks for the follow-up and those error codes. Yeah, those U0100 and U0101 codes are exactly what I saw on mine too! Actually, funny you mention the ground connections, my mechanic did check those first because it's usually a good starting point, but in my case, they were all fine. Since you're still under warranty (lucky you!), I'd definitely take it to the dealer. My warranty had just expired when this happened to me, typical timing right? The sudden onset after service is interesting, that's different from my experience since mine gradually got worse over a couple of weeks. Started with just unusual audio cuts, then escalated to the full electrical circus. Given the timing with your recent service, I wouldn't be surprised if something got loose or wasn't properly reconnected during the maintenance. One thing I learned from my experience, don't let them just reset the codes and send you on your way. Make sure they properly diagnose the root cause. My repair ended up being pretty simple once they found the actual issue, but it took some persistence to get there. Would you mind keeping us posted on what the dealer finds? I'm curious if it's the same connection issue I had. These electrical gremlins can be really tricky to track down in these newer BMWs.

Thanks so much for all that insight! Yeah, I'll definitely head to the dealer tomorrow and make sure they do a proper diagnosis rather than just clearing those codes. You've actually made me feel a lot better about this, was worried it might be something major with the electrical system that would take ages to fix. Makes sense about checking for loose connections after the service too, hadn't thought of that angle. I'll keep you posted on what they find. Really appreciate you sharing your experience, especially about being persistent with the diagnosis. Pretty sure the warranty will cover it, but at least now I know what to push back on if they try to just reset everything without finding the root cause. At least it's not just my car having these issues, seems like it's a bit of a known thing with our generation of BMWs!