Working on cars is a privilege, you first come in a car grab the key form your pocket you insert the key in the ignition you start it and right as it starts it doesn't start. You look at the dashboard, you see a check engine light and look at yourself and say there is a small problem or there is a big problem. Next you drive into your shop, jack up the car high up in the sky to look under the car to observe and look for any type of problems you look, and look, and see that on the side of the car that the gas cap isn't on. You're relieved to see that it was only the gas cap and nothing else major with the car now that is out of the way let's check it one more time to make sure. You slide out your key, stick it in the ignition and turn on the car and still see a check engine light.