Torque Converter Clutch: Description and Operation

Solenoid--mounted in the automatic transmission--locks-up the torque converter when activated by the ECM.
- When the vehicle reaches a specified speed the ECM energizes the solenoid---causing the torque converter to mechanically couple the engine to the transmission.
- When the brake is applied, or other conditions indicate that the transmission should operate as a normal--fluid coupled--transmission the ECM de-energizes the solenoid.