1-2 Shift Solenoid Valve
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The PCM energizes the normally open 1-2 shift solenoid valve, which blocks the 1-2 signal fluid from exhausting. The 1-2 signal fluid pressure is routed to both the 1-2 and the 3-4 shift valves.