Why is my chevy malibu 2017 check engine light on?

The check engine light in Your 2017 Chevy Malibu can be triggered by one of any number of sensors or systems in Your vehicle. The most common cause however is usually the emissions system. A fault or bad reading by any part in this system will trigger the warning light and will keep it on until the issue has been resolved. The first thing to check when You see the warning is Your fuel cap, on modern vehicles if this cap is left loose it can trigger a fault because the system doesnt see the pressure it expects in the gas tank. Beyond that the issues get much more difficult to correct, a bad 02 sensor, fuel injector or even a blown head gasket can all cause the check engine light to come on and should be looked at by a trained mechanic.