Shift Solenoid Valve: Solenoid 1, 2

The shift solenoids are 2 identical, normally open, electronic exhaust valves that control upshifts and downshifts in all forward gear ranges. These shift solenoid valves work together in a combination of ON and OFF sequences to control the line pressure and shift mechanisms.

Fig 1: View Of Shift Solenoid Valve

Courtesy of GENERAL MOTORS CORP.

Solenoid 1 controls the flow to each clutch valve by the operation type, that is, if solenoid 1 is ON, line pressure will be low: 87-116 psi (599-799 kPa) (6-8 bar). If solenoid 1 is OFF, line pressure will be high: 232-261 psi (1599-1799 kPa) (16-18 bar). The resistance is assumed to be 26-27Ω.

Solenoid 2 controls the oil flow to the lock-up clutch valve E by the ON/OFF signal.

The TCM monitors numerous inputs to determine the appropriate solenoid state combinations and the transaxle gear for the vehicle operating conditions.