1-2 Shift Solenoid Valve

The Powertrain Control Module (PCM) controls the ground for the 1-2 Shift Solenoid (1-2 SS) valve, thereby commanding the solenoid ON or OFF according to transmission and vehicle operation. When the solenoid is OFF, filtered line pressure that is fed to the solenoid will cease. When energized (ON), the exhaust port is blocked, stopping the exhaust of line pressure through the solenoid. Pressure on the end of the 1-2 shift solenoid valve moves the valve against a spring force, sending line pressure into the 1-2 shift solenoid fluid passage to the 3-4 shift valve.