Torque Converter Clutch Diagnosis

For electrical diagnosis of the converter clutch, refer to " General Motors Computer Controlled [1][2]Torque Converter Clutch Diagnosis" section.

The electrical system used to control the activation and deactivation of the converter clutch consists of a solenoid, 3rd clutch pressure switch located in the auxiliary valve body, brake release switch, electronic control module, throttle position sensor, vehicle speed sensor and either a vacuum or engine coolant temperature sensor mounted externally on the transaxle. The electronic control module receives information from the various sensors and, when vehicle speed is high enough, provides a ground for the solenoid, which activates the converter clutch. When operating conditions such as heavy acceleration indicate that the converter clutch be disengaged, the electronic control module removes ground from the solenoid and deactivates the system. The brake release switch opens the circuit and deactivates the converter clutch whenever the brakes are applied to prevent engine stalling. Some models are also equipped with a converter clutch relay to assist in the activation and deactivation of the converter clutch.

Before attempting to diagnose converter clutch electrical problems, mechanical checks such as linkage adjustments and oil level should be performed and corrected as needed.