1-2 Shift Solenoid Valve
WARNING: This page is about a different car, the 2004 Pontiac Sunfire, 2004 Chevrolet Classic, and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The normally open shift solenoid valve is de-energized and 1-2 signal fluid exhausts through the open valve.