Evaporative Emission (EVAP) Vapor Blocking Valve
The EVAP vapor blocking valve is a normally open valve, electrically closed by the PCM, to isolate the fuel tank from the rest of the EVAP system. This prevents the canister from becoming saturated causing hydrocarbons (HC) to be released into the atmosphere in a situation where the engine is OFF, and the ignition is ON during a drive cycle. The EVAP vapor blocking valve will automatically open to relieve excess pressure or vacuum, in the fuel tank, if the pressure or vacuum reaches a maximum calibrated value. The EVAP vapor blocking valve is located near the EVAP canister.