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

In the 2017 GMC Acadia, as well as other vehicles, You can consider the check engine light to be a sort of "catch all" for issues. It's nearly impossible to narrow down the causes for its illumination without reading the associated diagnostic trouble codes with an OBD-II scan tool, but I'll give You a few possibilities. An issue with the EVAP emissions system is typically the most likely cause on a '17 Acadia, and that can sometimes be as simple as a loose gas cap. It could also indicate that it's time to change Your spark plugs, or anything from a faulty thermostat to a bad downstream or upstream oxygen sensor. If You don't have access to an OBD-II scan tool to narrow Your diagnosis down a bit, most major automotive part stores will read Your codes for free.