I picked up my 428 in early January and it ran like a top until a couple of weeks ago. All my warning lights went off, moon roof froze, trunk wouldn't open but the car was essentially functional (engine, brakes, transmission.) Dealer finally replaced a very expensive circuit board that installs in the trunk called the REM - Rear Electronics Module? Rear Engine Module? Ran perfectly for 48 hours, then blew again and is now back in the shop.
I have seen messages about REM problems in the 3 Series but I seem to be the first I can find in a 4. Anyone have any knowledge about root cause of this failure? I can't think of anything other than thermal (ran fine in cold to cool outside ambient temps) or electrical - there is a pin or a pair of pins applying too much voltage or not enough somehow to one of the many components on that module and causing it to fall over. (It takes a couple of days from the first spurious warning message about something that's actually working to the point where you are receiving a message every 5 seconds.)
Sure would like to hear from anyone with experience on this in either a 3 or a 4 and what the ultimate outcome was.
I'm having the same exact problem on my 2014 435 More Sport. They replaced the REM and two days later car is doing the same thing. Every warning light possible is lighting up again. Not good for a $70k car. Did they ever get to the bottom of the problem? If so, what was the solution.