BMW M4 Infotainment Failure: MOST Bus System Issues?

Hey there! I have some experience working on cars and had a very similar issue with my 2018 BMW M3 last year. Super frustrating when these electronic gremlins pop up! After multiple attempts to diagnose it, my workshop found a faulty control unit in the MOST bus system that was causing the whole infotainment to go dead. The repair set me back about 1000 Euro, not cheap, but it fixed the problem completely. Can you tell me if your M4 is having any other electrical issues? Like unusual error messages or problems with other electronic systems? This could help narrow down exactly which control unit might be causing trouble in your case. From my experience with BMWs (I also owned a 4 Series), these MOST bus issues can be tricky to diagnose, but they're usually fixable once you identify the exact component that's failing.

Thanks for the detailed response! Same thing happened to me too, completely dead infotainment with multiple error codes. Had it serviced just 2 weeks ago at 195064 KM and everything was fine until yesterday. No other electrical issues that I've noticed, just this sudden infotainment blackout. Currently seeking quotes from different workshops since my warranty just expired. Crossing my fingers it's not as expensive as your repair! Anyone else here had a similar fix done for less?

Hey again! Good to hear back from you. Yeah, these MOST bus issues can be really unpredictable, my M3 actually did the exact same thing, working perfectly fine one day and completely dead the next. About the repair costs, I totally get you're looking for a better deal than what I paid. After my experience, I actually learned that some independent BMW specialists might do it for less. Just make sure they have experience with MOST bus diagnostics, because it can be pretty complex. Quick tip from my experience, before taking it to the shop, try disconnecting your battery for about 30 minutes. I tried this before going to the workshop (didn't work for me, but hey, worth a shot). Also, check your fuses if you haven't already. These are free troubleshooting steps that might save you some money. By the way, interesting that yours happened right after servicing. Mine went out completely out of nowhere. Might be worth mentioning this to the workshop that did your recent service, sometimes there can be a connection, and they might be more willing to help out even though warranty's expired. Let us know how it goes! These issues are pretty common in our cars, and sharing experiences helps everyone in the community.

Thanks so much for all the helpful advice! I tried the battery disconnect trick you suggested, no luck unfortunately. I've contacted a few independent BMW specialists and got quotes ranging from 600-900 Euro, which is definitely better than what you paid. You're right about mentioning the recent service, I called the workshop and they agreed to take a look at it for a reduced diagnostic fee since it happened so soon after their service. Really appreciate you sharing your experience with the M3. It's actually quite reassuring to know I'm not the only one who's dealt with this exact issue. Will definitely update the thread once I get it fixed in case anyone else runs into the same problem with their M4 in the future. These cars are amazing when everything works, but man, the electronics can really test your patience sometimes! Thanks again for all the help!