Check engine light

Both of those are fuel trim exceeded codes. P0170 is for bank 1 and P0173 is for bank 2. What this means is there is a perceived or actual problem with the vehicle resulting in a rich or lean condition. The computer has compensated by adding or lowering the amount of fuel the vehicle receives by more than 24%. Anything under 24% and there is no code set. Honestly, without a professional performing various pinpoint tests and examining the engine data, there is no other way to narrow this fault down. My advice is to seek out a BMW specialist for this one.

Thanks for your inputs. I had the issue checked out by a BMW specialist and he suggested I replace mass air flow sensor. I have put over 100 miles on the mistress and no check engine light. Ha, ha. Problem solved.

That is absolutely phenomenal news, Hot 540. I am glad to hear you went to a specialist that seems to have rectified your issues. Check engine lights on all cars are kind of a crap-shoot without true diagnostic data and pinpoint testing, yours is a true case of exactly that. Without any data, I would have shot at the fuel system first, here is turns out the MAF sensor was likely sending out errant readings, causing the computer to modify the fuel trim for the errant readings.

Though we couldn't help directly, I am glad that we were at least able to indirectly help :).