Lock-Up Control System Diagram

Lock-up released

• In the lock-up control valve, there is operating fluid pressure circuit connected into the lock-up piston and lock-up solenoid operates valve shift in response to a signal from the A/T control unit.

Therefore, the lock-up piston is not coupled.

Lock-up applied

Smooth lock-up control

• A/T control unit (TCM) controls current value that is output to the lock-up solenoid when shifting lock-up applied state from lock-up released state.

  Therefore the lock-up clutch is temporarily set to half-clutched state when shifting the lock-up applied state to reduce the shock.

• During the lock-up applied status, lock-up apply pressure is generated having the lock-up control valve to L/U by the lock-up solenoid.

  Therefore, press the lock-up piston to be coupled.

Half-clutched state

• Changes current value that is output to the lock-up solenoid from A/T control unit (TCM) to gradually increase lock-up solenoid pressure.

  In this way, the lock up apply pressure gradually rises and while the lock-up piston is put into half-clutched status, the lockup piston operating pressure is increased and the coupling is completed smoothly.