K 1500 Suburban 4WD V8-4.8L VIN V (2003)
Pressure Regulating Solenoid: Description and Operation
4L80-E/4L85-E
4L80-E/4L85-E
Transmission Pressure Control Solenoid Valve - Force Motor
The pressure control (PC) solenoid valve is attached to the valve body. The valve controls line pressure by moving a pressure regulator valve against
spring pressure. The PC solenoid valve takes the place of the throttle valve or the vacuum modulator, which was used on past model transmissions. The
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
PC solenoid valve from 0 amps, high pressure, to 1.1 amps, low pressure. The PC solenoid valve current is periodically pulsed in order to prevent
contamination from sticking the pressure regulator valve.
One diagnostic code is associated with the PC solenoid valve. Code P0748 sets when the PCM detects a difference of 0.16 amp or greater between the
amperage commanded and actual amperage. While the code is set, the PC solenoid valve turns OFF. Recovery can occur after the next ignition cycle.
Code P0748 does not sense a hydraulic condition. such as a stuck valve.
