Got the hill start assist inactive, DSC inactive, and cruise inactive, and no auto-reset on the turn signals, happened intermittently and then permanently in the course of a few hot days. Apparently this is fault 94BE though I did not check codes I knew the symptoms would likely be the SZL . This is a ~$500 part so not a fun bill to pay if you don't have to, and not something you can just walk down to wally world and get either. So knowing this was a potential E90 issue, I went and found this:
http://www.e90post.com/forums/showthread.php?t=520467
and cleared it right up, all I did was clean the encoder disc, I did not resolder anything. Will report back if the issue returns.
I would note that you should cover your M trim with something, the coating is very soft and will scratch easily. Mine was wearing at the touch points anyway so now I'm definitely replacing it.
Funny, the car hit 50,000 miles this week, the BMW "out of warranty" doomsday timer must have run out. It's been out of warranty for about a year and this is the first issue (of many more to come, I'm sure) that has come up
Just a friendly FYI for those searching here but not the E90 forums, as this issue is common to all E9x chassis cars (crud on the encoder disc)