Circuit/System Description

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The pressure switch manifold (PSM) is a multiple switch assembly made up of 3 normally open (N/O) pressure switches and 1 normally closed (N/C) pressure switch. Pressure switch 1 (PS1) monitors shift valve 1 positioning, pressure switch 2 (PS2) monitors shift valve 2 positioning and pressure switch 3 (PS3) monitors shift valve 3 positioning. The normally open pressure switches, PS1, PS2, and PS3, communicate the positioning to the transmission control module (TCM). The position of the shift valves 1, 2, and 3 is controlled by 3 normally closed shift solenoids 1, 2, and 3 (SS1, SS2, and SS3). When energized, the shift solenoids direct control main pressure to shift valve 1, 2, or 3, which strokes the shift valve. When the shift valve is stroked, an exhaust passage is blocked and fluid pressure to the pressure switch increases.