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.
De-energizes, allowing 1-2, 3-4 signal fluid at the 3-4 shift valve (362) to exhaust through the solenoid.