Pressure Control Solenoid (PCA)
WARNING: This page is about a different car, the 2006 Mercury Montego and 2006 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
The pressure control solenoid (PCA) is installed on the front valve body. Based on a signal indicating the degree to which the throttle is opened, engine torque, and according to a duty ratio predetermined in the TCM, the solenoids control line hydraulic pressure by linearly changing the comparable throttle hydraulic pressure. Through this, it controls operating hydraulic pressure to the clutch and brakes for smooth shifting. As a fail-safe function, if any shift control solenoid assembly abnormality occurs, the TCM will disable the current to the shift control solenoids. The line pressure is maximized, if the shift control solenoid assembly current is disabled when any abnormality other than locking occurs.