BMW Z4 Entertainment System Dead: MOST Bus Mystery

I had a similar problem with my 2012 BMW M3 last month. The MOST bus failure completely shut down my iDrive system, no audio, no navigation, nothing worked. The issue turned out to be a faulty MOST control unit in the amplifier. At the garage, they diagnosed it using specialized BMW diagnostic tools. They had to replace the fiber optic control module and reprogram the system. It wasn't just a simple plug-and-play fix. The repair took about a day and a half because they needed to ensure all control units were communicating properly after the replacement. It's definitely a serious issue that needs proper attention from someone who knows BMW systems well. DIY fixes aren't really an option here because of the complexity of the MOST network. You'll need a qualified technician with access to proper BMW diagnostic equipment. If your symptoms match what I experienced (complete entertainment system failure), it's likely the same issue. Make sure whoever works on it has experience with BMW MOST bus systems specifically.

Thanks for sharing your experience! That sounds exactly like what I'm dealing with. Mine's completely dead just like yours was. I'm relieved to hear it was fixable with the right expertise. Would you mind telling me roughly how much the repair set you back? Also curious if you've had any other issues pop up since they fixed it? Been considering whether I should get them to check anything else while they're at it.

Hey again! Just wanted to follow up about the costs and post-repair experience you asked about. The repair set me back exactly 1000 € to fix the faulty control unit in the MOST bus system. I'm happy to report that since getting it fixed at the mechanic, the entertainment system has been working perfectly, no more black screens or system failures! You know what's funny? I was just as worried as you about potential future issues, but honestly, everything's been running smooth as silk since the repair. The iDrive, sound system, and navigation are all working exactly like they should. The mechanic did a thorough job testing all the connections after the repair, which probably explains why it's been so reliable. If your symptoms are identical to what I experienced, you're probably looking at a similar solution. While they're in there, it probably wouldn't hurt to have them check the other components connected to the MOST bus, but in my case, fixing that one control unit was all it took to get everything back to normal. Let me know if you need any other details about the repair, happy to share more from my experience!

Just got back from the mechanic, and wow, what a different experience from my last one! Took your advice about finding someone who knows BMW systems, and it really paid off. The issue was exactly what you described, a faulty MOST control unit. Mechanic diagnosed it right away with their BMW-specific tools. Total repair cost came to 950 €, pretty close to what you paid. They replaced the fiber optic module and reprogrammed everything. The whole job took about a day, but the results are fantastic. My entertainment system's working perfectly now, got my music, navigation, everything's back up and running. Really appreciate you sharing your experience, it gave me the confidence to get this sorted properly. The mechanic even checked the other connected systems while they were at it, just to be safe. Everything's looking good, and I'm finally enjoying my Z4 the way it's meant to be. Thanks again for the help!