Circuit Description
WARNING: This page is about a different car, the 2005 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
The pressure control (PC) solenoid valve regulates actuator feed fluid passing through the solenoid into torque signal pressure. The TCM uses a pulse width modulated signal in order to control the torque signal pressure. The TCM compares various inputs in order to determine the appropriate pressure for a given load. The TCM varies the current to the PC solenoid from 0.1 amps, for maximum line pressure to 1.1 amps, for minimum line pressure. An internal current monitor within the TCM provides feedback in order to determine actual PC solenoid valve current draw.
If the TCM detects a continuous open or short to ground in the PC solenoid circuit, then DTC P0748 sets. DTC P0748 is a type C DTC.