1-2, 3-4 Shift Solenoid (SS) Valve (315)
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
Energizes to prevent fluid from exhausting out of the line passage and the 1-2, 3-4 signal fluid passage.