Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The shift solenoid (SS) valve 1 is part of the lower control valve body. The SS valve 1 is a normally closed (NC) solenoid valve and controls fluid to the clutch select valve 3- and related clutches. During this diagnostic test, intrusive actions are taken by the transmission control module (TCM) to test the SS valve 1 to see if the valve is stuck OFF. When in first gear engine braking, if first gear ratio is not achieved in a predetermined period of time and the closest gear ratio detected if fourth, the TCM commands second gear and if second gear ratio is attained this indicates a stuck OFF SS valve 1 and the DTC will set.