Clutch C-8B, 4T60 Torque Converter Clutch Electrical Diagnosis, 3.1L PFI A & W Bodies: Notes

Fig 1: Clutch C-8B, 4T60 TCC Circuit Diagram (3.1L A Body)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Clutch C-8B, 4T60 TCC Circuit Diagram (3.1L W Body)

Courtesy of GENERAL MOTORS CORP.

The purpose of the Torque Converter Clutch (TCC) feature is to eliminate power loss of the torque converter when the vehicle is in a cruise conditions. When the solenoid coil is activated by the ECM, the torque converter clutch is applied, resulting in a straight through mechanical coupling from the engine to the wheels. When the transmission solenoid is deactivated, the TCC is released, which allows the torque converter to operate in the conventional manner (fluidic coupling between engine and transmission).

1. This test checks the functional operation of the TCC circuit.
2. This test checks the TCC control driver in the ECM.
3. This test will confirm there is battery voltage to terminal "A".
4. This test will confirm that ECM has the ability to turn on TCC.