What the Light Means
The "check engine" light is part of your car's onboard diagnostics (OBD) system. Since the 1980s, computers control and monitor vehicle performance, regulating such variables as engine speed (RPM), fuel mixture, and ignition timing. In some vehicles, the computer also tells the automatic transmission when to shift.

When the computer finds a problem in the electronic-control system that it can't correct, the computer turns on a yellow warning indicator that's labeled "check engine," or "service engine soon.” This light could also be a picture of an engine, known as the International Check Engine Symbol, perhaps with the word "Check." In addition to turning on the light, the computer stores a "trouble code" in its memory that identifies the source of the problem, such as a malfunctioning sensor or a misfiring engine. The code can be read with an electronic scan tool or a diagnostic computer, standard equipment in auto repair shops.

Tips if Your Check Engine Light Comes On
Check your dashboard gauges and lights for indications of low oil pressure or overheating. These conditions mean you should pull over and shut off the engine as soon as you can find a safe place to do so. On most cars, a yellow "check engine" means investigate the problem giving you time to schedule an appointment to have your vehicle diagnosed.

- Try tightening your gas cap. This often solves the problem. Keep in mind that it may take several trips before the light resets. - In most cases, your probably better off to bring your vehicle to the shop where we have specific diagnostic computers that we can hook up to your vehicle and read the stored code(s) that caused the light to come on.
Follow the link below to watch a video

http://edenautomotive.mynapatools.com/2013/10/24/check-engine-light/