Faulty Check engine light?

[Mel K]

Two days ago my check engine light came on and stayed on. Called the dealer for an appointment. Then yesterday, started it up and went through the startup sequence and the check engine light went out. Stayed out all day. Today, again the light did not stay on. It's a 2003 GT Stage I autostick with 36k miles. Several months ago the same thing happened with the oil light, but that corrected itself. Don't want the dealer to flash the computer. Any thoughts on this?

[bobs turbo pt]

unfortunately without the light on the dealership will use there famous line of "sorry we couldnt get the problem to happen " unless there is an error code stored have you checked for that ?? put the key in the ignition turn it forward to just before starting(dont start it though) and back 3 times see if any codes pop up at were the milage shows

[hharper1321]

quote:Originally posted by Mel K

<snip>Several months ago the same thing happened with the oil light, but that corrected itself.</snip>

How exactly did that correct itself? Did your car drink some oil on it's own, or what?

[purple04]

When the light comes on while driving, that means the problem is there (current). If the lights goes out later or on another startup, that means the problem is not current. It will still be stored in history and can be read for a while (~50 starts). After that, if the problem doesn't come back it's cleared from history.
All the code testing is based on the problem being there. This means that if the wire, connector or component isn't bad DURING testing, it can't be found.
If you have a cat and a fish at home, and the fish disappears while you are out, you can guess what happened, but if you catch the cat with his face in the bowl and the fish in his mouth, you KNOW what happened. If you have 50 cats, which one is the bad one? That's what intermittent problems are like to find. I'd suggest checking the history codes to get an idea of the area of the problem, but there is no point in trying to diagnose it unless the light comes back on. It would be a best guess unless the problem can be duplicated.

[Mel K]

Back from the dealer. Did the expensive 36k service. They didn't flash the computer and didn't find any problem. I think that it may have been a situation where the gas cap was not sealed tightly causing the engine light to come on. Car is running great.

[bobs turbo pt]

hopefully it doesnt come back !! [8)]