Fuel Vapor Vent Valve
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, 2011 Ford Fusion, 2010 Mercury Milan, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The fuel vapor vent valve is a PCM-controlled solenoid that isolates the fuel tank from the rest of the EVAP system. The fuel vapor vent valve is a normally open valve allowing the flow of vapors from the fuel tank to the electronic EVAP canister purge valve and the EVAP canister. The PCM controls the fuel vapor vent valve on/off cycle whenever it is desired to isolate the fuel tank from the rest of the EVAP system.