Hydraulic Control System
WARNING: This page is about a different car, the 2004 Suzuki Swift + and 2004 Chevrolet Aveo. However, it is still accessible from the selected car via links, so may be relevant.
Based on the hydraulic pressure created by the oil pump, the TCM sends signals to the solenoid and the hydraulic control system governs the hydraulic pressure acting on the torque converter, planetary gear, clutches, and brakes in accordance with the vehicle driving conditions.