Diagnosis - 700-R4: Description: Notes

NOTE: This article contains test charts that are part of General Motors Computerized Engine Controls. Only those charts required to test Torque Converter Clutch (TCC) system are included. Other diagnostic codes may appear while performing TCC electrical diagnosis. For complete information on General Motors Computerized Engine Control systems see COMPUTERIZED ENGINE CONTROL articles in ENGINE PERFORMANCE section.

The Torque Converter Clutch (TCC) assembly consists of a 3-element torque converter with the addition of a converter clutch. The converter clutch is an internal mechanism with friction material attached to front face. It is splined to the turbine assembly in converter.

The purpose of the torque converter clutch feature is to eliminate power loss due to slippage when vehicle is cruising. This allows the convenience of an automatic transmission and the fuel economy of a manual transmission.

When the TCC solenoid is activated, the torque converter clutch is applied which results in a straight through mechanical coupling from engine to transmission. When TCC solenoid is deactivated, the torque converter clutch is released which allows the torque converter clutch to operate in a conventional manner.

Fig 1: Torque Converter Assembly With TCC

Courtesy of GENERAL MOTORS CORP.