Solenoid Tank Valve
WARNING: This page is about a different car, the 2004 Ford Pickup Heritage. However, it is still accessible from the selected car via links, so may be relevant.
The tank valve solenoid is normally closed. When the ALT fuel switch is placed in the ALT position, the solenoid receives VPWR from the inertia fuel shutoff (IFS) switch through the ALT fuel relay. This opens the solenoid allowing CNG fuel flow to the fuel rail solenoid. The AFCM will close the tank valve if the gaseous fuel system pressure drops below 517 kPa (75 psia).