January 18th, 2008 by Steve Cypher

It’s a beautiful day and you’re out enjoying every minute of it in your car. All of a sudden, you look down at your instrument panel and notice an orange light that says “check engine” or “service engine”. Is this a real problem? Is your engine about to seize, leaving you stranded in the middle of nowhere (that’s usually when it happens)? Well…

What does it mean?

The check engine light is part of your cars on board diagnostic system (OBD for short). It’s designed to let you know if something is not right with what seem like a gazillion systems that your cars computer constantly monitors. Although it shouldn’t be ignored, there are a number of things that you can do for peace of mind before you take it to a repair shop to have it checked out (yes, you eventually will need to do that).

“Should I pull over to the side of the road and call a cab?”

No, not necessarily. If your engine is running roughly then you should either pull over and park, or proceed to the nearest repair shop as soon as possible. A rough engine could mean you need major repairs, and continued driving could cause further damage. If everything seems normal, continue driving until you find a convenient spot to safely leave the road then park your car and…

Check your gas cap.

Really. Most vehicle fuel systems are “closed” and, therefore, if you forget to either tighten, or even screw on, your gas cap, it will trip a sensor and – bingo! – on comes the blasted light. Once you do this, many times the system will reset itself in a matter of miles and the light will turn off.

Check under the hood for moisture

Water has a wonderful way of shorting things out. With all the wires and sensors located in the engine compartment, it can cause havoc with all the electronic goodies located there.

Have it checked out

If the light remains on, take your car to a dealer or repair shop, where they can diagnose the problem. Your cars computer not only tells you when there is a problem, it will also record the problem in its innards (called a fault code). Repair shops have machines that can read and diagnose these codes and let you know what needs to be done to correct the problem. If the light goes out, mention it to your mechanic when your have your can in for an oil change. They can retrieve the information and let you know just what happened, so you can avoid the problem in the future.


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Ms. Lewis

I just read your article regarding cause for check engine light to go on & stay on. I drive a 1993 Chrysler & my local dealer’s repair department said my car is too old for their equipment to diagnose the problem. My car does run rough since the light came on, however the mechanic said if the light does not flash, it’s ok to keep driving it. He wanted to charge me a fortune to change the plugs & wires “to see” if that was the problem. I had a neighbor do that instead, but the light is still on. What else could be the problem? I don’t want to spend tons of money for the repair shop to just “try” different things.
Please help me if you can.

Steve Cypher

Ms. Lewis,

Since the check engine light responds to any number of issues, suggesting one over the other would be a guess, at best. There is a way to read the fault codes of your vehicle without a diagnostic tool. According to Roland Finston, a Chrysler expert at allexperts.com, you can do this yourself:

“Fortunately the controller can sense whether there is a problem with most of these components and record a fault code in its memory. You can access these codes with your ignition key. So I would check for stored codes first.

Begin a readout as follows: Take your ignition key and turn the ignition switch “on-off-on-off-on” and leave it “on”. Do this switching quickly so that no more than 5 seconds elapses. Then watch the ‘check engine’ light to begin to flash, pause, flash, pause, etc. Count the number of flashes before each pause and make a note of them in the order that they come. The last two flash groups will be 5 in each. Repeat the readout until you have the numbers accurately (the same result, two times in a row). Then pair the numbers two at a time in the order they came, to form two-digit numbers, for example the last number will be 55 which is the code for ‘end of readout’. ”

Once you have the fault codes, you can visit the following web page to contact Mr. Finston:


Best of luck.

Melani Fox

Your vehicle’s wheels are one of those items that require regular maintenance and replacement to keep your car or truck working well and safely. Nothing’s nastier than the squeal of spent braking system pads except, maybe, the high cost of substitute at a repair center with no scruples.




Steve Cypher

By the looks of your email, you live in the U.K. Amazing to think that you actually have a 98 Sunfire and even more amazing that it runs “perfect.” That being said, the only thing that appears to be wrong is the fact that the check engine bulb hasn’t burned out yet. You might try and take it to a dealer to have the fault codes checked. If there are no dealers or garages with this type of diagnostic equipment where you live, you might try replacing the gas cap and proceed up the scale from there.

Matthew S.

Hey I have a 2000 cavalier and what happens when the engine light comes on the temperature gauge on the dash board drops and the temperature gauge shuts off as soon as the engine fan turns on?

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