EVAP system is a vapor recovery mechanism designed to prevent the escape of unburned fuel system vapors containing hydrocarbons into the atmosphere. When fuel vapors expand in the fuel tank due to temperature rises, they are sent through the EVAP two-way valve and temporarily stored in the EVAP canister. Canister purge valve (CPV) is controlled by Powertrain Control Module (PCM), which opens under certain conditions to admit fuel vapors from canister to intake manifold where they mix with incoming air before entering combustion chambers as well burning out. EVAP system includes various components such as EVAP canister, air filter, canister vent shut valve, two-way valve/bypass solenoid valve assembly, and fuel tank pressure sensor. The EVAP Canister Filter blocks harmful particulates from getting into your engine. Maintenance will generally involve checking for fuel smells, examining hoses and connections as well as professional diagnosis using an OEM scan tool for more complex problems. Specific procedures must be adhered to when replacing some parts such as: Evaporative emission (EVAP) canister purge valves; Canister close valves; Fuel tank pressure sensors; and EVAP vent solenoids themselves. The electrical connector and EVAP hoses are disconnected first before ensuring proper directional alignment during installation on the purge valve of an evaporative emission (EVAP) canisters. Depending on model year, this is behind the fuel tank or on the evap itself. Electrical connectors have to be disconnected, hoses taken off and then finally take out this device for new one after removing it off its place completely. In 2004 or later models could be found either in engine compartment or under vehicle depending upon its manufacture year period where it's situated at varies with each subsequent model update respectively remove mounting brackets disconnect one hose take other down followed by putting things back together again reverse order o f operation raise car remove one bracket bolt let go from the side reinstall this bracket removing those components related during after having loosened fasteners.