My check engine light just went on for the second time. The car is a 95 M3 wit about 41,000 miles. The first time the light went on was at about 39,000 miles, when the car was still under the basic warranty. I took it to the dealer and they "fixed" it kbut were unable to tell me why this happened. Both times it happened while the car was warming up about 5 minutes after a cold start. The car runs fine. I'm sure I can get the dealer to "fix" it again this time, but I'm not comfortable running back there every 3 months for something that supposedly doesn't mean anything. Is there anything I should insist on? Is this stuff covered by the longer pollution control warranty?