Chart C-8 Torque Converter Clutch - 4.3L Turbo PFI: Notes

Fig 1: Chart C-8, TCC Circuit Diagram (4.3L Turbo PFI)

Courtesy of GENERAL MOTORS CORP.

Fused battery voltage is supplied to TCC solenoid through TCC brake switch. ECM will engage TCC by grounding circuit No. 422 to energize solenoid. TCC will engage when:

• Vehicle speed is above 30 MPH.
• Engine is at normal operating temperature.
• Throttle position not changing, indicating a steady speed
• Brake switch is closed and transmission is in 3rd or 4th gear.
  NOTE: Test numbers refer to test numbers in diagnostic chart.
  1. If test light glows, battery voltage and continuity through TCC solenoid.
  2. Using a scan tool, check for vehicle speed sensor signal (VSS) to ECM.