Fuel Injector Control Valve
WARNING: This page is about a different car, the 2013 Ford F-550 Super Duty, 2013 Ford F-450 Super Duty, 2013 Ford F-350 Super Duty, and 2013 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The fuel injector control valve is a hydraulic check valve that allows the high fuel pressure to bleed off into the fuel return chamber directly above it, when the piezo actuator is energized and the valve piston pushes down on it.