What would cause my 2008 Chevy Equinox check engine light to come on?

In the 2008 Chevrolet Equinox, and in just about any other vehicle as well, there are a huge number of reasons that the check engine light may illuminate. Your best bet is to get Your vehicle scanned with an OBD2 scan tool; if You don't have one of Your own, You'll be able to go to many major automotive part stores and they'll read the codes for free. The most common reason is usually a fault with the EVAP system, though that's far from the only cause. Specifically, You may have a loose gas cap, a damaged or degraded fuel filler neck, a bad purge canister, or other issues with the fuel system. However, in order to pinpoint the cause, You're really going to need a more specific diagnostic code.