NegativeLift

How do you check if your check engine light is working?

areyouasian

there are various things that will trip a CEL...for instance...if you dont screw down gas cap tight enough the CEL will come on...or just unplug an O2 sensor that will trip a CEL too...just set up one of those situations and you will see if it turns on...if it does, then it works...then reset the ecu to turn off the CEL....

Brian_92GSR

It'll come on for a second or two when you first turn the car on.