Circuit/System Description

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The line pressure control (PC) solenoid is part of the control solenoid valve assembly which has no serviceable parts. The normally high line PC solenoid regulates and directs the PC solenoid oil pressure to the isolator/pressure regulator valve. Increasing PC solenoid line pressure increases transmission line pressure. The TCM varies the current to the line PC solenoid through a low side driver. Decreasing the current to the line PC solenoid increases line PC solenoid oil pressure by closing OFF the solenoid exhaust port. Increasing the current to the line PC solenoid decreases line PC oil pressure by opening the solenoid exhaust port. Line PC solenoid power is supplied by the TCM through a high side driver (HSD). The HSD protects the circuit and components from excessive current flow. If excessive current flow is detected, the HSD will turn OFF. When the fault is corrected the HSD will reset.