So I'm driving home today and There is a light on my dash lit up. I'm Thinking what the hell is that? Looks like a Movie camera? Nah thats not it. What is it? So I get Home and look in the book, it's the service engine soon light. Remembering the loose gas cap thing from Somewhere, I check it. It barely on at all, soo I tighten it down. Restart the Car, the Light is still on. I can Assume it was'nt becuase the gas cap was loose? I did notice a very strong gasoline smell when I Started it this morning. But the light was'nt on during the drive to work. Saturn l200 2.2 liter.

Well, I know sometimes it does that because of the gas cap, and you need to give it a chance to repressurize and readjust...it's happened to my dad on his bimmer before...if you give it a day or so it should go away if the gas cap was the problem...

SES codes don't turn off automatically. Sometimes you even have to turn it off with an OBD scanner and hope it doesn't come back on.

Driving home today. Decided to pass someone, hit 4000 Rpm tranny shifted and the light went out.

It's normally because of the gas cap as you've mentioned. However if it was loose, it's smart to take it off and leave it off for a few minutes to let pressure back out. Then tighten it back on. Also it won't go off automatically as Satty mentioned. Often times pressure has build back up then the light will go off.

My name is satty now? How dare I be compared to that mullet wearing post whore :P

Also it won't go off automatically as Satty mentioned. Often times pressure has build back up then the light will go off.

[post="11405"]<{POST_SNAPBACK}>[/post]

Whaaaaa????? I posted without know it. Damn, I hate it when that happens. :P
Its a brain fart, it happens to everyone, I'd rather a BMW freak be mistaken for me than that Camaro ricer dude.

Anyways, it is entirely possible that the cap was loose because the gas in the tank is afraid of the dark, so let the cap off, light a match and drop it in there so the gas feels safer.

Thats a horrible idea, by the way, never do that.

the sad thing is, some people would actually listen to you if you didn't add the disclaimer...

You set a P0440 . The usual service advisor suggestion is check to see your gas cap is tight . Since you didn't mention you got gas recently , you probably have a leak in your canister evap system . At the dealer , your system gets checked with pressure system and vacuum sys , then using a smoke machine we check for leaks . I do not recommend going to an independent shop for this ck engine light because they will just start changing parts until the light goes off , and the fact that the car doesn't test the evap sys all the time , this can get frustrating . Good luck

You set a P0440 . The usual service advisor suggestion is check to see your gas cap is tight . Since you didn't mention you got gas recently , you probably have a leak in your canister evap  system . At the dealer , your system gets checked with pressure system and vacuum sys , then using a smoke machine we check for leaks . I do not recommend going to an independent shop for this ck engine light because they will just start changing parts until the light goes off , and the fact that the car doesn't test the evap sys all the time , this can get frustrating . Good luck

[post="11463"]<{POST_SNAPBACK}>[/post]

The Gas cap was very loose. Not even in the threads. The first few times I tried to tighten it, It would'nt thread at all and would lift right off.
But anyway The light went out today. So wish me Luck that it stays out.

My mom does this all the time in the pickup truck. The light comes on, she freaks out and I go and tighten the gas cap. Then I say to her "mom, make sure the gas cap makes the little clickity noise when you close it up"

My '01 Silverado won't even start if the gas cap is off. It also won't start on the first try after the battery has been pulled. GM has tons of saftey systems in this department apparently.