LOCK-UP CONTROL: System Description: Description

• The torque converter clutch piston in the torque converter is engaged to eliminate torque converter slip to increase power transmission efficiency.
• The engagement/release of the lock-up clutch is operated by the lock-up control valve by switching the operating hydraulic pressure feed circuit to the lock-up piston chamber.

  The switching of the lock-up control valve is operated by the torque converter clutch solenoid valve according to the drive signal from the TCM.

• If the CVT fluid temperature is low or the vehicle is in fail-safe mode due to malfunction, lock-up control is prohibited.

Lock-up Released

In the lock-up released state, the torque converter clutch control valve is set into the unlocked state by the torque converter clutch solenoid valve and the lock-up apply pressure is drained.

In this way, the torque converter clutch piston is not coupled.

Lock-up Applied

In the lock-up applied state, the torque converter clutch control valve is set into the locked state by the torque converter clutch solenoid valve and lock-up apply pressure is generated.

In this way, the torque converter clutch piston is pressed and coupled.