Why is my chevy volt check engine light on?

If You want to know why the check engine light has come on on Your Chevy Volt, I can help give You some answers. One of the most common reasons for a check engine light to turn on is due to a loose or defective gas cap. Sometimes after we fuel we won't pay much attention to how we close the gas cap. Most of us don't know that not tightening the gas cap enough can throw up a check engine light. This is why it's important to tighten it all the way so we don't scare ourselves when the light comes on. Some other reasons are a bad oxygen sensor, failing spark plugs, issues with the catalytic converter, and a bad mass airflow sensor.