Torque Converter Clutch (TCC) Diagnosis

TORQUE CONVERTER CLUTCH (TCC) DIAGNOSIS
To properly diagnose the Torque Converter Clutch (TCC) system, perform all electrical testing first and then the hydraulic testing.
The TCC is applied by fluid pressure which is controlled by a solenoid located inside the Valve Body. The solenoid is energized by completing an electrical circuit through a combination of switches and sensors.


Functional Check Procedure
Inspect
1. Install a tachometer or scan tool.
2. Operate the vehicle until proper operating temperature is reached.
3. Drive the vehicle at 80 to 88 km/h (50 to 55 mph) with light throttle (road load).
4. Maintaining throttle, lightly touch the brake pedal and check for release of the TCC and a slight increase in engine speed (rpm).
5. Release the brake, slowly accelerate and check for a re-apply of the converter clutch and a slight decrease in engine speed (rpm).