Lock-up Control
Shift solenoid valve D controls the hydraulic pressure to switch the lock-up shift valve ON and OFF. When the PCM turns shift solenoid valve D and A/T clutch pressure control solenoid valve A ON, lock-up starts. A/T clutch pressure control solenoid valve A regulates and applies hydraulic pressure to the lock-up control valve to control the degree of the lock-up.
The lock-up mechanism operates in all five gears in D, in 3rd gear in D3, and in 3rd and 4th gears in S.