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Check engine light

I have a 2000 Saturn with a little over 70,000 miles. I maintain this car faithfully.

My check engine light came on the other day.

My trusty mechanic did diagnostics and it was a only needing a new fuel cap.

I got gas three days later and the light came on again about 24 hours later.

They replace the fuel cap again. This time it is really hard to get off.

When I left the shop the second time, the light was still on. They told me it would reset after driving it.

It didn’t. They reset it manually.

I know there are people that drive for years with the check engine light on. It makes me nervous.

It is off now - I am nervous about it coming on and flashing.

If the light is off, and stays off, you have nothing to worry about. The CEL is an early warning system, not a message of impending doom.

The light may come on for any number of possible reasons. It’s not just a gas cap warning.

The important thing is not to ignore the light. If it comes back on have it checked. It could be something much more serious, but you’re always better off finding out what it is sooner rather than later.

Your car probably set a DTC (Diagnostic Trouble Code) light for an EVAP (evaporative control) system leak. Since an improperly tightened gas cap (“three clicks more”) is sometimes the cause, some people, mistakenly think that is always the cause. Not so. A very small pin size hole, in the gas tank, filler neck, filler cap seal, vacuum and fuel lines to and from the gas tank can cause a light to come on. It can be very difficult, and expensive, to find, and repair the leak.
If the light is on because of the EVAP system, don’t worry about any negative effect on the engine. If the check engine light is already on for one thing, it can’t come on and warn you of any other problems that might occur.

One more addition to this excellent post: If you have periodic state inspections for pollution, they won’t inspect it if the CEL is on. If you don’t have an inspection or it isn’t due for a while, it gives you some time to figure out the problem.

And another thing (OK, that’s two things…) is that it takes several starts to reset the code. Don’t expect it to go away immediately.

I know there are people that drive for years with the check engine light on. It makes me nervous.

It is wise to be nervous. As long as the light is on, you don’t know is something really bad happened because the light was already on and you did not know to get it checked. Keep being nervous.