I just bought a 2014 Dodge Avenger brand new. The salesman made sure that the car was ready for me and that it had a full tank of gas. I picked it up from the dealer late last night and I noticed my "check engine light" was on. I was thinking it may be that the gas cap was loose but I know it can be a number of things, major or minor. Can I get some clarity on possibilities? It's a new car but no car is perfect.
The check engine light can come on because of a faulty oxygen or mass airflow sensor, bad spark plugs or faulty catalytic converter.
Since it is a brand new vehicle there should not be a problem taking it back to the dealership and having the problem fixed under warranty. If after that it continues to come on and cause problems check the "Lemon laws" for vehicles in your state.
〉 Answered on Feb 4th, 2014 by Colleen McGee, Driving Instructor at Americas Driving School
Yes, a loose gas cap can throw a code setting the check engine light on. If this is the case, typically, after a few key cycles this should reset itself as it is a soft code not requiring a scan tool hook up to turn off.