Circuit Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 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 three normally open (N/O) and one normally closed (N/C) pressure switches. The E pressure switch monitors E shift valve positioning and relays it to the transmission control module (TCM). When E pressure switch is in the open state, E shift valve should be in the unstroked position.
DTC P0873 is a type A DTC.