Torque Converter Clutch Solenoid: Description and Operation

TORQUE CONVERTER CLUTCH PULSE WIDTH MODULATION SOLENOID VALVE
The PCM controls the Torque Converter Clutch Pulse Width Modulation Solenoid valve (TCC PWM Sol valve) by varying its operating duty cycle (ON/OFF time) from 0% to 100%. Until the transmission is operating in 3rd gear, the TCC PWM Sol valve is OFF. In this state, filtered PWM feed pressure flows at maximum pressure through the solenoid and into the PWM circuit.
When the TCC PWM Sol valve is energized, the valve operates at 32 Hz (cycles per second) and from 0% to 100% duty cycle depending on vehicle operation. The TCC PWM Sol valve is enabled to modulate the amount of PWM feed pressure passing through the solenoid, sending it to the converter clutch regulator valve. At 0% duty cycle, the torque converter clutch applies at minimum capacity. At 100% duty cycle the clutch applies at maximum capacity.






TORQUE CONVERTER CLUTCH SOLENOID VALVE
The Torque Converter Clutch Solenoid valve (TCC Sol valve) is an ON/OFF solenoid that functions in the same manner as the 1-2 shift solenoid valve and the 2-3 shift solenoid valve. As with the shift solenoids, the PCM provides the ground to command the TCC Sol. valve ON or OFF. The only difference in operation is that ignition voltage is supplied through the normally closed brake switch to the solenoid.
When the solenoid is OFF, and if the transmission is operating in third or fourth gear, the TCC signal fluid exhausts through the solenoid. When energized (ON), the exhaust port is blocked. This allows the TCC signal fluid pressure to move the converter clutch valve against the spring force and the line pressure at the opposite end of the valve.