Fuel Tank Isolation Valve (FTIV)
The FTIV is a PCM-controlled solenoid that isolates the fuel tank from the rest of the EVAP system. The FTIV 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. Whenever it is desired to isolate the fuel tank from the rest of the EVAP system, the PCM provides a variable duty cycle signal (between 0% and 100%) to the solenoid which controls the FTIV operation.