What would cause my 2015 Ford Explorer check engine light to come on?

The Check Engine Light in Your 2015 Ford Explorer is used by the vehicle to warn You when something in Your emissions system is operating outside of its standard paRameters. This can be something as simple as leaving the gas cap off all the way to something as serious as a blown head gasket. The first thing to check is going to be the gas cap, the ecm reads the pressure inside the gas tank to make sure none of the fuel vapors are leaking out which would cause fuel economy issues and be bad for the environment. If that isnt Your problem the next most likely cause would be a bad 02 sensor which You can test using an ODB2 scanner.