Torque Converter Clutch: Description and Operation

The ECM controls a transmission mounted electrical solenoid. When vehicle reaches a specific speed, the ECM energizes the solenoid, causing the torque converter to mechanically couple the engine to the transmission. When operating conditions indicate transmission should operate as a normal fluid-coupled transmission, solenoid is de-energized, and transmission returns to normal automatic operation when brake pedal is depressed.
Diagnosis of intermittent problems should be a visual and physical inspection of the connectors involved in the affected circuit. Some causes of the problems are: improperly formed terminals or connector bodies, damaged terminals or connector bodies, corrosion, body sealer, or other contaminants on the terminal mating surfaces, incomplete mating of the connector halves, terminals not fully seated in the connector body (``backed-out'' terminals) and inadequate terminal crimps to the wire.