There are almost 3,000 possible trouble codes that could turn on a check engine light. Asking us to guess which one is at fault in your case is simply impossible. Get the codes read with a code reader, at an auto parts store, or at a shop. Those are your only options.

Buy an obd ll scanner from ebay for about 20$ and never have to take your car in just to check the light

Obey the light. Check the engine or if you are unable to do so have someone do it for you. This may involve the exchange of money.

Interrogate the computer. Check for fault codes. If you don't know what I'm talking about, go to a large auto parts store and ask them if they can interrogate your computer.

The clue is in the name of the light......

So its on, what are we suppose to do about it?