Lock-up Clutch Mechanism The Torque Converter Clutch (TCC) is hydraulically controlled by an electronic pressure regulating solenoid (EPRS4) which is controlled by the EAT ECU. This allows the torque converter to have three states of operation as follows: l Fully engaged l Controlled slip variable engagement l Fully disengaged. The TCC is controlled by two hydraulic spool valves located in the valve block. These valves are actuated by pilot pressure supplied via a solenoid valve which is also located in the valve block. The solenoid valve is operated by PWM signals from the EAT ECU to give full, partial or no lockup of the torque converter.