fuel tank pressuree sensor on 2004 Chevrolet Colorado

Where is the fuel tank pressure sensor located on a 2004 Chevrolet Colorado and are they easy to change them? Also, I tighten my fuel cap and on the dash it comes on the dash fuel cap. what would be causing that problem

Asked by for the 2004 Chevrolet Colorado
large evap leak. the sensor is part of the fuel pump module. it is on top of the tank and the tank must be dropped to gain acess.

Ok thank you. When I tighten the cap it goes off. Is it from the cap not fitting properly?