BMW 7 Series Audio & Nav Dead: MOST Bus System Issue?

Hey there! I have some experience working on cars and had a similar issue with my 2014 BMW 5 series (also owned a 3 series before). The symptoms you're describing sound exactly like what I dealt with. My entire infotainment system went dead one day, no sound, no navigation, nothing. After pulling my hair out for a bit, I took it to my trusted workshop. They diagnosed a faulty control unit in the MOST bus system. The repair wasn't cheap, set me back about 1000 Euro, but it fixed everything completely. Could you share more details about when this started happening? Did it die suddenly or was it acting up before? Also, which error codes did you pull? This would help me tell if you're dealing with the same issue I had. BTW, these MOST bus problems aren't uncommon in BMWs from that era. Best to get it checked by a professional who knows their way around BMW electronics.

Thanks for sharing your experience! Mine actually died suddenly while driving last week. Just one moment everything was fine, and then complete silence, super frustrating! My car's done 150328 KM and just had its service last month, so this caught me off guard. The error codes I pulled were MOST40301 and MOST40302, which point to a communication failure. Hearing that your repair cost around 1000 Euro is actually a bit of a relief, I was worried it might be even more expensive! Think I'll take it to the shop this week. Thanks again for the detailed info, really helpful!

Hey again! Thanks for those extra details. Yeah, that sudden failure while driving is exactly what happened to me too! And those error codes you mentioned (MOST40301 and MOST40302) are the same ones I got with my 5 series. Really takes you by surprise when everything just goes silent, right? Actually, looking back at my repair invoice, the total came to 1100 Euro because they had to replace both the control unit and some fiber optic cables that had deteriorated. The technician told me these cables are pretty sensitive to heat and vibration over time. With your mileage being similar to what mine was when it failed (I was at about 145000 KM), it's probably the same issue. Quick tip from my experience, when they fix it, ask them to check all the fiber optic connections while they're in there. I didn't do this the first time, and six months later, I had a minor issue that could've been prevented. Better to get everything checked while they're already working on it. Let me know how the repair goes! Always curious to hear if others have the same experience I did with these BMW electronics. Good luck with the fix!

Thanks so much for the additional tips! Just booked my car in for next Tuesday. It's good to know I should ask them to check those fiber optic connections, definitely don't want to deal with this again in six months! Really appreciate you sharing all those details about your repair experience. Your suggestion about heat and vibration issues makes total sense too, I do a lot of driving, so that could explain why mine failed. I'll update you once I get it back from the shop. Fingers crossed it's just the control unit and cables like in your case. Thanks again for all the help, you've saved me a lot of worry about what I might be facing with this repair!