I had similar errors, but not exactly the same. I had the following faults all at once: DSC, Active Steering, Tire Pressure Monitor. My car is a 2007 335i.
I found this post the most helpful, you should check it out. It's a DIY to fix the faults. It is really well done. If you don't want to touch your motherboard and reflow connections with solder/paste, then I would just clean the optical disc:
http://www.e90post.com/forums/showthread.php?t=520467
On other posts, the consensus is that it will cost about $1,300 to completely fix with new optical disc and board (with new IR sensors, etc...) My dealer gave the same quote.
BTW, I drove my car for about 3 weeks with these faults. Dealer said it wouldn't be a problem.
I am pretty good friends with the service guy at my dealership and he offered to replace just the optical disc for $150 using the SZL Repair Kit:
http://www.ebay.co.uk/itm/BMW-SZL-Re...-/300880850396
He said it had a 70-80% chance of working and thankfully it did.
To tell you truth, the DIY was so well written, I was tempted to do it myself, but my friend said that you need to be careful with static electricity and dust on the disc...I figured $150 was a fair price anyway so had him do it.
When I got the disc back, I understood why the IR sensor was having a hard time calibrating...it was coated with white, crystal-like substance...looked like a bunch of snowflakes. Pic 1 is a close up of this, while Pic 2 shows the whole optical disc next to a quarter...not as big as I thought it was going to be.
Anyway, hope this helps.
