what does it mean when emission light comes on
Re: What does it mean when the emissions light comes on... It could be emission related- the gas cap may be on tight but how about when you filled up before?And the cap can actually be bad - meaning it allows to much fuel vapour to escape. Your cap actually has to pass a pressure test during a drive-clean inspection.
Possibly an O2 sensor malfunction. A majority of the Emissions or Check Engine light indications are from these sensors, especially if the car still runs well. Newer cars may have two O2 sensors - one before the catalytic converter and one after.