Chart C-8B, 4T60 Torque Converter Clutch Electrical Diagnosis - 3.3L PFI A Body: Notes

Fig 1: Chart C-8B, 4T60 TCC Circuit Diagram - (3.3L PFI A Body)

Courtesy of GENERAL MOTORS CORP.

Each gear switch opens when appropriate clutch is applied. All gear switches are open in 4th gear. TCC will engage under the following conditions:

• Engine is warmed up.
• Vehicle speed above a calibrated value of about 35 MPH.
• Throttle position not changing, indicating a steady speed.
• Transmission 3rd gear switch closed.
• Brake switch closed.
  NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. This test checks integrity of total circuit minus TCC solenoid.
  2. This test checks for faulty brake switch or open circuit No. 422.