I m currently dealing with the same problem too, I suspected just right after I replaced the two front stock headlights on my (01 x5 4.4i) the same day at night while headed out, when I started the car, the air bag light is on and wont go out. I bought the sr5 16 pin tool peak on eBay for $119 and read the codes: 03 & 05. At this point, according to the book, I thought it was related due to a faulty seat belt receptacle for the passenger front seat. I went and bought one for$138 from bavauto and replaced it correctly, unfortunately problem still appears with the same two codes when I clear it & comes right back on. My friend told me to try replacing the two factory headlights back to its place and see if the problem persist. Any idea guys?