One problem related to service engine light on has been reported for the 2008 BMW X3. The most recently reported issues are listed below.
Service engine soon light came on. Diagnosed at dealership that it was the dmtl pump that senses and gas leaks. I was told by service manager that it was out of warranty and I didn't have to replace it since I lived in PA in an area that didn't require it to work under our state inspections. The only problem was that the service engine light would be on and I would not know if something else was wrong with the car. Later I was talking to service manager at Lexus who was a former BMW service manager who stated it was covered under PA emission laws. I contacted manager at BMW who informed me that I would have to contact BMW. I registered a complaint with BMW who came back 3 weeks later denying any coverage. When asked why gentleman could not answer stating he was not a technician. I repeatedly stated from my research that PA adopted California emission law in 1996 and from my understanding it should be replaced by BMW. Once again I was told no coverage and I asked if his 3 weeks of research involved a corporate attorney. He would not answer. It appears that a BMW buyer is given 4 year warranty because after that everything is denied with no explanation as to why. This dmtl pump is a sensor for fuel leaks and could really cause a serious accident if not replaced. I believe PA emission laws understand the hazard and that is why they state it should be replaced. This problem with BMW goes back over 10 years according to internet forums. . I cannot understand why they have not been held accountable and made to correct this hazardous situation.