Spark

Fourth Gear (Lock-Up)

When the lock-up control execution conditions are met, the torque converter clutch (TCC) solenoid applies pilot pressure to shift valve B. Pilot pressure passed through shift valve B operates the lock-up control valve to drain oil pressure from the lock-up clutch release side of the torque converter and to raise oil pressure at the engagement side. The TCC solenoid is duty-controlled.

When the conditions are met when driving at higher than a certain speed in 3rd (overdrive OFF) or 4th (overdrive ON) gears, the transmission control module (TCM) outputs a signal to the TCC solenoid and locks up the lock-up clutch in the torque converter. This is the lock-up control. Lock-up control is operated by the TCC solenoid and the lock-up control valve.