I had the same problem in my '08 3.0si. iDrive controller would work intermittently. Then it died completely.

Dealer quoted me $500 for the new module that sits under the trim, so I called a couple BMW salvage yards to see if they might have one. They did. $100 shipped. Plugged it in and it worked perfectly, no coding was necessary. Has worked flawlessly for 2 years now.

My understanding is that if it is a brand new module that has never been installed, it will need coding. But, one that has been taken out of another vehicle shouldn't. Of course I could be wrong, but it worked for me.