I just wrecked my audi two months ago. I had hot rodded it significantly. My check engine light would come on all the time for stupid stuff. Nothing that affected the performace of the car accept having an annoyed driver having to stare at a check engine light. Most times it went on when I pushed it hard. All the extra air flow from the huge turbo would scare the computer. The On Board Diagnostic systems on these cars are very sophisticated. I would venture a guess that the crossfire is no different especially since most of the parts are Benz. German engineering baby!!! Take your car to the dealership as soon as you can. If you need to wait because you have stuff to do then make sure you dont tell them youve been driving it around with that light on. I hope its something minor like a loose connection or an air flow issue, you have any mods done? My mechanic hated the On Board Diagnostics, most times it comes on for silly reasons, but sometimes its something serious. Dont ruin your baby!!! Good Luck!!!