What would cause my 2017 GMC Sierra check engine light to come on?

A loose-fitting gas cap is the most common reason why the check engine light comes on in a 2017 GMC Sierra. Always make sure You twist the cap on securely when You're done at the pump. A faulty oxygen sensor is a common cause, as well. This sensor plays an important role in the health of the catalytic converter. Not addressing this issue promptly can result in expensive repairs. If the spark plugs in Your Sierra aren't sparking correctly, they will trigger the light, as well. If this is the cause, Your vehicle will mIS Fire, which is pretty easy to identify. Another cause is an issue with the mass airflow sensor. This generally is triggered by a d***y or old air filter that hasn't been replaced regularly. Lastly, a problem with the catalytic converter can be to blame, as well. This is generally the most expensive repair to deal with when Your check engine light comes on.