Shift Solenoid Valves: 1-2 and 2-3

The shift solenoid valves are two identical, electronic exhaust valves that control upshifts and downshifts in all forward gear ranges. These valves are normally open. These shift solenoid valves work together in a combination of ON and OFF sequences in order to control positions of 1-2, 2-3 and 3-4 shift valve trains. The PCM/TCM monitors numerous inputs to determine the appropriate solenoid state combination and transaxle gear for the vehicle operating conditions.






IMPORTANT: The solenoid states are normally ON (1-2) and OFF (2-3) in the P, R, and N gears. However, these may change based on the vehicle speed and throttle position.

The PCM/TCM energizes the shift solenoid valves by providing a ground to the solenoid's electrical circuit. This sends current through the coil winding of the solenoid, thereby creating a magnetic field. The magnetic field repels the plunger inside the solenoid. This seats the solenoid metering ball against the fluid inlet port. This action prevents exhaust of fluid through the solenoid. It then provides an increase in fluid pressure at end of shift valves. This fluid pressure initiates an upshift by moving the shift valves.

The resistance on shift solenoid valves should measure between 19 - 24 ohms when measured at 20°C (68°F) and between 24 - 31 ohms when measured at 88°C (190°F). The shift solenoid valves should energize when voltage is greater than 7.5 volts. The shift solenoid valves should de-energize when voltage is less than 1 volt.