Transmission Pressure Control Solenoid Valve (Force Motor)

The Pressure Control Solenoid valve is attached to the valve body. The valve controls line pressure by moving a pressure regulator valve against spring pressure. The Pressure Control Solenoid valve takes the place of the throttle valve or the vacuum modulator, which was used on past model transmissions.

The VCM/PCM varies line pressure based on engine load. Engine load is calculated from various inputs, especially the TP Sensor switch. Line pressure is actually varied by changing the amperage applied to the Pressure Control Solenoid valve from 0 amps (high pressure) to 1.1 amps (low pressure). The Pressure Control Solenoid valve current is periodically pulsed in order to prevent contamination from sticking the pressure regulator valve.

One diagnostic code is associated with the Pressure Control Solenoid valve. Code PO748 will set when the VCM/PCM detects a difference of 0.16 amp or more between the amperage commanded and actual amperage. While the code is set, the Pressure Control Solenoid valve will be turned OFF. Recovery can occur after the next ignition cycle. Code PO748 will not sense a hydraulic problem such as a stuck valve.