Torque Converter Clutch Solenoid (TCC)

Torque Converter Clutch (TCC) Circuit:

Purpose:
The Torque Converter Clutch (TCC) eliminates the power loss due to the "slipping" of the torque converter stage when the vehicle is in a cruise mode by creating a mechanical link between the engine and transmission. The clutch is operated by fluid pressure and applied when a computer controlled solenoid in the transmission (TCC solenoid) is energized.

Operation:
The TCC system uses a solenoid operated valve to provide fluid pressure to the torque converter clutch for engagement. The TCC solenoid gets electrical power when the ignition is turned "ON", and becomes energized when the PCM completes the circuit to ground. When energized, the solenoid allows a check ball to lift off of its seat allowing fluid pressure to apply the converter clutch. The PCM will energize the TCC solenoid only when certain conditions are present (see below).

^ Internal transmission fluid pressure must be within a specific range.
^ Engine must be in closed loop operation.
^ Vehicle Speed Sensor (VSS). Speed must be above a certain value before the clutch can apply.
^ Coolant Temperature Sensor (CTS). Engine must be warmed up before the clutch can apply.
^ Throttle Position Sensor (TPS). After the converter clutch applies, the PCM uses the information from the TPS to release the clutch when the car is accelerating or decelerating at a certain rate.
^ Gear Select Switch. The 4th gear switch inputs to the PCM. The PCM uses the 4th gear switch signal for TCC engage and disengage points for 4th gear only.
^ Another switch used in the TCC circuit is a brake switch which opens the 12 volt supply to the TCC solenoid when the brake is depressed, turning the solenoid "OFF" and disengaging the TCC.

Location:
The TCC solenoid is installed in the transmission valve body.