Opening the gas tank on a 2016 Cadillac XTS is easy—all you have to do is unlock the vehicle’s doors, push in on the rear center edge of the fuel fill door, and release it. Once you do this, the fuel fill door should automatically pop open, exposing the gas tank fill spout.
Seeing as the 2016 Cadillac XTS uses a capless refueling system, you won’t need to unscrew a gas cap to begin refueling—simply insert the fuel nozzle into the fuel tube and make sure it latches to start pumping fuel.