I've had my 2001 X5 for about a 1-1/2 years now and I love it! There is nothing better! However, I've got a funny but still scary check engine light that comes on and turns off without any signs of problems or issues. I've had it serviced and the light is turned off via computer but it turns back on after weeks or days..The truck runs awesome but this light is simply strange. I've got 156000 miles in it and all is good but this light is simply strange. Could it simply be a oxygen sensor that wants to go bad? Please shed some light in to this weirdness..