Line Pressure Relief Valve
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The solenoid body assembly contains an over-pressurization relief valve that will limit the line pressure through the (Pressure Control Solenoid A (PCA)) solenoid and feedback to the pump main regulator valve. The Line Pressure Control (LPC) relief valve controls line pressure spikes when cold. If this valve fails, concerns may be seen with the filter found in the solenoid body assembly.