Originally Posted by Roleez
I believe I have the answer for you. My old 06 550i flashed all the codes you mentioned back in mid-2006. Turned out to be a common problem affecting a lot of E60s and a rare few E90s as well.
It's the steering angle sensor (SZL is the BMW code for the failed part). Once that fails, brake light turns yellow, DSC stops working, brake assist won't hold at a stop on a hill, and FTM stops working. Covered under warranty (hopefully you're still within 4yr/50k).
+1 Happened to our '06 330i 2 weeks ago. If you happen to put on your turn signal you may notice that it flashes, but will not turn off automatically. I told our SA that and he said "it sounds like your SZL sensor is bad". That was indeed the problem