A/T System Description - Lock-Up System

A/T System Description - Lock-Up System

Lock-Up System

The lock-up mechanism operates in D (during accelerating: 1st, 2nd, 3rd, 4th, 5th, and 6th gears/during decelerating: 2nd, 3rd, 4th, 5th, and 6th gears), S with automatic shift mode (during accelerating: 1st, 2nd, 3rd, 4th, and 5th gears/during decelerating: 2nd, 3rd, 4th, and 5th gears), and S with sequential sportshift mode (during accelerating: 1st, 2nd, 3rd, 4th, 5th, and 6th gears /during decelerating: 2nd, 3rd, 4th, 5th, and 6th gears). The pressurized fluid is supplied through a lock-up fluid passage in the torque converter, causing the torque converter clutch in the torque converter to be engaged. As this takes place, the mainshaft rotates at the same speed as the engine crankshaft. The PCM controls the shift solenoid valve C pressure and A/T clutch pressure control solenoid valve D pressure to optimize the lock-up timing and the amount of the lock-up. The shift solenoid C pressure operates the lock-up shift valve to switch the lock-up ON and OFF. The A/T clutch pressure control solenoid valve D pressure operates the lock-up control valve to control the degree of lock-up.

Torque Converter Clutch Lock-Up ON (Engaging Torque Converter Clutch)

The fluid pressure is applied to the lock-up fluid passage (94) in the torque converter, causing the torque converter clutch in the torque converter to be engaged and then the turbine and the torque converter cover to be engaged. The mainshaft rotates at the same speed as the engine crankshaft when the torque converter clutch in the torque converter is engaged.






Torque Converter Clutch Lock-Up OFF (Disengaging Torque Converter Clutch)

When the fluid pressure to the lock-up fluid passage (94) in the torque converter is blocked, the torque converter clutch in the torque converter is released. The turbine and the torque converter cover are also released at this time, causing the mainshaft and the engine crankshaft to rotate at a different speed.