What causes my 2017 chevy malibu emissions check engine light to come on?

A loose gas cap is the most common reason for a check engine light to come on in a 2017 Chevy Malibu. Escaping fumes can trigger the light, and usually, just tightening the gas cap fixes the problem. If it doesn't, You might have a crack or worn spot in the seal of the cap. A bad oxygen sensor is a common cause, as well. If a failed sensor is ignored, it can cause damage to the catalytic converter and spark plugs. Issues with the spark plugs, spark plug wires, or ignition coils can cause the light to come on, too. Replacing these parts can be done with pretty basic tools, if You don't feel like paying the labor for the service work. One of the more serious reasons for the light to come on is failure of the catalytic converter. In the 2017, Malibu, replacing this part will run You between $1,330 and $1,380.