Smooth Lock-up Control
WARNING: This page is about a different car, the 2006 Nissan Quest. However, it is still accessible from the selected car via links, so may be relevant.
When shifting from the lock up released state to the lock up applied state, the current output to the torque converter clutch solenoid is controlled with the TCM. In this way, when shifting to the lock up applied state, the torque converter clutch is temporarily set to the half-clutched state to reduce the shock.
HALF-CLUTCHED STATE
The current output from the TCM to the torque converter clutch solenoid is varied to steadily increase the torque converter clutch solenoid pressure.
In this way, the lock up apply pressure gradually rises and while the torque converter clutch piston is put into half-clutched status, the torque converter clutch piston operating pressure is increased and the coupling is completed smoothly.