Torque Converter Clutch: Description and Operation

Comp. Loc:

PURPOSE
The Torque Converter Clutch (TCC) system is designed to eliminate power loss by the converter (slippage) therefore increasing fuel economy. By locking the converter clutch, a more effective coupling to the flywheel is achieved. The converter clutch is operated by a solenoid controlled by the Engine Control Module (ECM).

OPERATION
The TCC solenoid valve, under the control of the TCC Relay, opens and closes the automatic transmission oil passage to lock and unlock the torque converter clutch.

The information which the ECM uses to determine control of the TCC relay is provided by the following sensors:

^ Throttle Position (TP) sensor (throttle opening)
^ Camshaft Position sensor (CMP)
^ Engine Coolant Temperature (ECT) sensor
^ Vehicle Speed Sensor (VSS)

The ECM turns the TCC relay "ON" only when the following condition are satisfied.

^ Engine is running
^ Engine coolant temperature is above 60°C (140°F)
^ Throttle valve opening is between 6.4° and 64.5°
^ Brakes are not applied
^ Vehicle speed is greater than 75.4 km/h 46 mph.