I accidently put way to much "Mystery Oil" in my SL 600 gas tank and sure enough, half a tank later the Check engine light came on. My theory is the oil inthe gas contaminated my oxegon sensor (sensors?) and I am using a gasoline system cleaner to clean them off. Anyone agree with me on this? It has always passed California smog tests with flying colors and I can't believe it is anything else but the oil damage. Do I have to take a clamp off a battery post to turn off the light check engine light in case the sensors are cleaned? Runs great. You can see why i do not want to take it to a dealer cause you know its gonna be a grand no matter what.