I own a 99 S80 T-6, and for about 9 months now I get "check emissions control" on my msg. panel with a check engine light. The msg. has stayed on for several months now. The engine is running fine as far as I can tell. I hate to have to bring it in and spend two hundred dollars just for a possible reset. Is there a something I can do to extinguish the warning or doI have to bring the car in for service. Thanks! Dave '95 850/ '99 S80 T-6

Dave,
Unlike your 850, the s 80 especially 99, Its a dealer issue. If your dealer charges 200 bucks to find out the code then they are thieves! it shouldnt be more than a hundred if you are out of warranty! If its been on for months I would say its likely a o2 sensor which you have 4 of. If you got the money take it in to see what the code is, you dont have to fix it, if not then wait till your car runs bad or maybe dies. I know that sounds bad but if it was a serious engine problem you would have known by now. Im guessing a oxygen sensor, which will just affect you gas mileage and perhaps a bad odor from your car.

Removing the engine control module fuse or disconecting the battery for 10 minutes will clear the check engine light and reset the adaptives for the fuel system. There are countless possible reasons for the warning light. Vacuum leaks, mass air sensor, o2 sensors, boost control valve, temp sensors, exaust leaks, low oil pressure (causes variable valve timing problems) as well as faults in other systems such as transmission or ABS.

its a defective sensor; it will cost you about $300 to $400 for a new one. This is a common problem and should be covered by Volvo but it aint... happened to me also