Circuit Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The 2-3 shift solenoid (2-3 SS) valve controls transmission fluid pressure acting on the 1-2 and 2-3 shift valves to position the valves for the appropriate gear. The 2-3 SS valve is a normally-open exhaust valve located on the control valve body. A fused circuit supplies ignition voltage to the 2-3 SS valve. The TCM commands the solenoid ON or OFF by switching the ground path. When the 2-3 SS valve is commanded ON, the TCM senses low voltage. When the 2-3 SS valve is commanded OFF, the TCM senses high voltage. Refer to Shift Solenoid Valve State and Gear Ratio .
If the TCM detects a continuous short to voltage in the 2-3 SS valve circuit, then DTC P0977 sets. DTC P0977 is a type A DTC.