where is the evaporative emission system vent valve/solenoid circuit located? on 2007 GMC Sierra 1500

just had the check engine light come on and the code was PO449

Asked by for the 2007 GMC Sierra 1500
vent valve is above or around the fuel tank. the 449 only says there a control issue, it never identifies a bad part just a failed system. you better get it check first before spending the money to buy the valve.

ok thanks