Evap sensor?

There is no EVAP sensor, there is the EVAP system that uses multiple parts to test the system and detect leaks. If it determines there is a leak it then sets a code. Those parts are the fuel tank and lines, the EVAP purge and vent valves as well as the charcoal canister leak detection pump and the fuel tank pressure sensor. I'm assuming you have a code set? What is the code? That would give us a starting point as to where to look.

P0451 code

OK, that is the fuel tank pressure sensor performance out of range. The PCM cannot read the signal correctly so it sets this code. Commonly it is due to a failed sensor or corrosion in the connection at the sensor. It is located on top of the fuel tank, plugged into the top of the fuel pump module. Testing it can be difficult as space is limited. The book tells you to drain the fuel tank, then lower it and test or replace the sensor from the pump. However it can usually be replaced without that IF you can reach in between the tank and the box if the pump and level sender are working OK and you don't plan on replacing them. It is a tight fit and in many cases I will at least loosen the fuel tank straps to gain some extra space.
These will give you a better idea of the process.
https://www.youtube.com/shorts/3xPyGDo4M2A
https://www.youtube.com/watch?v=ki1aXClsivY