You don't mention what make or model car you have, so I'll tell you about my car, instead.
When my check engine light comes on, it means the computer is adjusting things because a sensor is out of normal values. The light is just to let me know that, and that I should check my sensors to see where the problem lies.
On older cars, it used to mean that the battery was not charging, and was then truly a warning light.
What it means in your car, well, that all depends on what kind of car you have, and you didn't tell us that.
There is much that "depends" with this question, especially the year, make and model of vehicle. Most 90's and newer vehicle "check engine" light situations are a signal that something is wrong with optimal operation of the engine, usually related to one of the many emission sensors. My "check engine" light comes on when I do not properly secure my gas cap, for instance. (2005 Pontiac SV6 minivan) So, you should check your gas cap and if the light continues to come on, try to feel or hear any difference in how the engine is operating. If you think the engine is running differently than before, take the vehicle in for service sooner than later. Either way, you should have it checked out.
A check engine light now a days is usually an emission problem. Can you drive the car? yes. If it works, drive it. You might get bad gas mileage, but without knowing what is causing the light to come on it is hard to say. When you go to get it state inspected, you will not pass the emissions test, but they will tell you exactly what is wrong so you can have it fixed.
Ok, what you can do is go to your local Auto Parts store and get them to to a diagnostic test (it's usually free) and they can tell you exactly what it is . Good luck !
The Check Engine Light detects a multitude of problems. In some vehicles the light will be saying;"You have an emission control device needing service" or "You have left your fuel cap loose" or a multitude of other things. It may only need a simple a minor correction or a major correction. Only a mechanic can answer this for sure!
what cause a check gas cap light come on ever now abd then i have repalce it with new one but still comes on after a while ehay cause this please let me let me know thanks
It may simply mean you should have your engine checked?
Is it a red or yellow light? On most, the red is for charging system or oil problems,the yellow is for emission,computer sensors,loose gas cap. If it starts and runs okay,take it by an auto parts store for a free test,or drive it! I have seen cars go forever with a check engine light on,or unhook positive battery cable for awhile and hook back up and see if light is out.
You can very well drive it around with the light on, but it is advisable that you rectify the error as soon as possible.If there is nothing wrong with the engine, you can take the help of http://www.automotix.net/autorepair/diy/ which will enable you to rectify the problem in your vehicle.
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