Check engine code P0453

My 05 subaru impreza 2.5l non-turbo check engine light came on so I brought the car to Partsource and they checked the computer and got code P0453 “Evap system presure sensor signal to high, or low”, I can’t remember. He erased the code and the check engine light has not retured. Is this somthing I should be concerned about? And what could have caused the code?

a typical cause is a loose gas cap.

did you fill up just before the light came on?

when you (or anyone) fills up the tank tighten the cap until it clicks twice. (this is from the manual)

if the light still comes on you may have a bad gas cap gasket. see if the cap is on tight, and drive it for a couple days.

Yes, the cap was tight. The day the light came on it was very hot outside and cool the night before. After the guy checked the code I removed the gas cap and there seemed to be too much presure in the tank. It made sound like air being forced under presure.

Is it standard today (and for the OP car) for the vehicle to be equipped with a leak detection pump? The purpose of these pumps were to pressurize the evaporative emission system (check for leaks)? this was standard on BMW very early in the decade.I have seen failed leak detection pumps and damage done to evaporative emission tubing during fuel tank removal,sender/pump replacement.