The light on the dash came on and I pulled the code and P0441 P0455

I check the lines from the tank to the engine and every thing is fine. The Valve by the air box we checked and its working. I bought a new gas cap just to be on the save side.. How do I check the valve by the canister to see if it is working? This on a 2008 Scion TC 88,000 miles..

Our computer activates it. Do some research on the boards. You might find some common thread.