BMW X6 Entertainment System Dead: MOST Bus Diagnosis

Hey there! I had the exact same MOST bus failure in my 2020 BMW X4 M40i last winter. The system completely died, no audio, no iDrive, black screens everywhere. After diagnosis at the garage, they found a faulty fiber optic ring controller in the MOST network. It was actually the amplifier unit that was causing the entire system to fail. They had to replace the amp and reprogram the whole MOST system. Not a quick fix, took them about two days to complete everything. It turned out to be quite serious since the MOST bus controls pretty much all infotainment functions. You really need someone who knows BMW systems well. These issues can't be fixed with basic diagnostic tools, they need proper BMW software to reprogram everything. You're right to be careful about where you take it. I'd strongly suggest going to a dealer or a certified BMW specialist for this one. Regular shops often can't handle MOST bus programming properly. Best of luck with the repairs.

Hey, that's really helpful, thanks for sharing your experience! I'm facing the same nightmare with my X6 right now. Really sounds identical to what you went through. Just wondering, do you remember roughly how much the whole repair set you back? Also, has everything been working smoothly since they fixed it, or have you noticed any other quirks pop up? Thanks again for the heads up about going to a proper BMW specialist. Definitely gonna skip the regular shops for this one.

Hey again! Great to hear back from you. Yeah, I can totally help with those questions since I've been through this headache. So after seeing the BMW specialist, they sorted out that MOST bus issue completely, haven't had a single problem with the entertainment system since then. Everything's working exactly like it should: perfect sound, navigation, the whole deal. The repair bill came to 1000 € for fixing the faulty control unit in the MOST bus network. Not exactly cheap, but considering how complex these systems are, and more importantly, that it actually fixed the problem for good, I'd say it was worth every cent. Just a heads up, once they fix it properly like they did with mine, you shouldn't see any other weird issues pop up. My system's been running smooth as silk since the repair. The key really was going to someone who knew exactly what they were doing with these BMW systems. These MOST bus problems can be super tricky if you don't have the right diagnostic tools and know-how. Let me know how it goes with yours!

Thanks so much for all the details! Just wanted to update you on what happened with my X6. Finally got it fixed last week, and you were spot on about everything! Took your advice and went to a BMW specialist. They found the same issue, a faulty control unit in the MOST bus system. The repair took about three days because they had to order some parts, but wow, what a difference! The whole entertainment system is working perfectly now, crisp sound, responsive screens, everything. The bill was pretty much what you said, around 1000 €. Definitely not cheap, but after seeing how much work went into it and all the specialized equipment they needed, I get why. Plus, like you said, better to get it done right the first time. Really appreciate you sharing your experience, saved me from wasting time at regular shops that wouldn't have been able to handle it. The specialist even showed me all the diagnostic steps they took, which made me feel much better about the whole thing. Thanks again for helping me out with this!