Shift Control Mechanism

To perform hydraulic control, shift control, and lock-up control of the automatic transmission, the PCM controls shift solenoid valves A, B, and C, line pressure solenoid valve A, and automatic transmission (A/T) clutch pressure control solenoid valves A, B, C, and D. The PCM switches each solenoid valve ON and OFF. This changes the positions of the shift valves in the valve bodies which open and close ports to send hydraulic pressure to the appropriate clutch. A/T clutch pressure control solenoid valves A, B, C, and D control the clutch pressure regulated by each of them, which allows smooth shifts and lock-up of the torque converter.