2004 emission problems with SES light on?

My service engine soon light has been on so I called onstar and had them diagnose it for me and they said it was an emission problem and could be as simple as tightening my gas cap down but either way it didnt look like a big problem. I tried tightening the gas cap but the light didnt go off. Has anyone else had a similar problem?

If it was your gas cap (not being tight enough) then it will take a few days for the light to turn itself off.

If it was your gas cap (not being tight enough) then it will take a few days for the light to turn itself off.

Is this a common problem with the gas cap or has other people experienced emission problems?

This can happen to any car with the OBD computer system. It happens to a lot of people, fill up with gas and turning the gas cap "only" a couple of clicks is not enough on some cars to seal the cap tight. It could be a bad gas cap/seal or something in the emission system, who knows? Since yours is a 04, it should still be under warranty and the repair will be covered.

If the light doesn't go out within a couple of day of driving, you should take it in and have the dealer check it out.

This can happen to any car with the OBD computer system. It happens to a lot of people, fill up with gas and turning the gas cap "only" a couple of clicks is not enough on some cars to seal the cap tight. It could be a bad gas cap/seal or something in the emission system, who knows? Since yours is a 04, it should still be under warranty and the repair will be covered.

If the light doesn't go out within a couple of day of driving, you should take it in and have the dealer check it out.

Yeah it still isnt out so i guess i will take it in even though I dont want to.

The emissions system is under warranty for 70K miles. It shouldn't cost you anything for the dealer to repair the problem other than your time and the hassle of having to go to the dealer. I hope they get it fixed the first time rather than you having to make repeated trips.

The emissions system is under warranty for 70K miles. It shouldn't cost you anything for the dealer to repair the problem other than your time and the hassle of having to go to the dealer. I hope they get it fixed the first time rather than you having to make repeated trips.

I wasnt aware the emission system was something that could cause problems. Seems to me a car this new shouldnt have any problems.

Actually the majority of the problems you will experience with your car will be caused by the emissions system. The EGR valve and the O2 sensors are a major area of problems. Evaporative emission controls will also give you problems. Yes it may take a while but it will happen. Hopefully, you will be one of the lucky ones that only has minor problems. The EPA knew that the cars would have problems meeting regulations and that is why the manufacturers must guarantee that the car will pass emissions tests for up to 70 or 80k miles.

Is this something that can cause the car to stall or not start? It is a relatives car that will get taken in but if it wont effect the way it runs I might wait until it warms up.

Should start and run without problems. You may notice that the SES light is on but that should be about all. Good Luck.