What are some reasons my check engine light came on in my 2007 Kia Optima?

Hello, there are many reasons a check engine light could come on. The only real area you can handle without technically troubleshooting is to ensure your fuel cap is securely fastened. If it is loose, evaporative emission system testing during vehicle operation cannot successfully occur, and the light will come on. This will happen during normal driving. All other causes will require hands on troubleshooting to find out which fuel, ignition, air intake or emissions system area is malfunctioning.