check engine light on 1998 Plymouth Neon

what could be the problam with the check engine light staying on.can't get car inspected

Asked by for the 1998 Plymouth Neon
Clean the gas cap gasket and the gas filler mouth real well. Worked for me.
2 answers
There can be many many reasons for a check engine light coming on, just look at this list of codes that will turn it on: http://repairpal.com/obd-II-code-chart
Do you know which codes your vehicle has stored in the engine control module?