Q: Check engine light on

The Check Engine Light (CEL) could have illuminated for many reasons of course inasmuch as there are thousands of Diagnostic Trouble codes that could set the CEL. You can borrow a Code Scanner from Autozone and manually force the reset. Of course, prior to doing that, be sure to download and record ANY diagnostic trouble codes, if the fault you are experiencing is NOT reported by the Code scanner as simply a loose gas cap. Also, note that if the check engine light did come on due to a loose gas cap, it can take multiple ignition cycles for the light to reset by itself (again, a Code Scanner can be used to force an immediate reset). If the problem causing the CEL to set is due to a fault other than a loose gas cap, I recommend you request a check engine light diagnostic at the conclusion of which the Mechanic will let you know of the cause of the fault and the repair strategy and cost.