When your check engine light comes on, most people end up taking there car to a mechanic. You then have to trust the mechanic to let you know what's really wrong and hope that it won't cost too much money. But if your check engine light comes on, there are two easy things you can do first that will cost you nothing.

First, try tightening your gas cap. If the gas cap is not completely tightened, this will affect the pressure in your emissions system and it will cause the check engine light to come on. This is the number one reason for the check engine light coming on.

Second, take your car to a major chain of auto parts store such as a Auto Zone, Checker, Car Quest, etc. Most of these stores have the hand-held electronic device that connects to the diagnostics system in your car and they are usually more than happy to plug it in and see what the computer on your car thinks is wrong. Often times it will be a aberration that caused the light to come and you won't need to waste an entire day taking your car to the mechanic to get fixed. If there is something wrong, at least you have an idea on what to expect and if your mechanic comes back with something else, you'll know that you are getting ripped off.