2003 pontiac sunfire check engine light comes on when there seems to be nothing

[Arlene]

wrong.? A week ago my check engine light came on so I had the mechanic test it and nothing came up so he reset it and last night it came on again. Are they realy called "idiot lights" sometimes? Do they come on when there is nothing wrong? I hope there isn't.

 

[sun2001fire]

Mine came on simply because the gas cap wasn't on tight enough. Nice to know that a guy at domo can cost you $50 to have your car scanned for nothing. I have heard this is fairly common for newer cars, the engine light comes on just because something in the computer isn't quite right. It would be nice if once the gas cap is tightened the light would go off, but once it is on, its on until a scanner clears the code.