Chart C-8A, 3T40 Torque Converter Clutch Electrical Diagnosis 2.3L PFI N & W Bodies: Notes

Fig 1: Chart C-8A, 3T40 Torque Converter Clutch Circuit (2.3L N Body)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Chart C-8A, 3T40 Torque Converter Clutch Circuit (2.3L W Body)

Courtesy of GENERAL MOTORS CORP.

Voltage is supplied to TCC solenoid through brake switch and transaxle second gear apply switch. ECM will engage TCC by grounding circuit No. 422 to energize solenoid.

TCC will engage when:

• Vehicle speed is above 34 MPH.
• Engine is at normal operating temperature.
• Throttle position not changing, indicating a steady speed.
• Brake switch and transmission 2nd gear switch are closed.
  NOTE: Test numbers refer to test numbers in diagnostic chart.
  1. Light off confirms transmission 2nd gear apply switch is open.
  2. By 25 MPH, transmission 2nd gear TCC switch should close. Test light will light and confirm battery supply and closed brake switch.
  3. Grounding diagnostic terminal with ignition switch on, engine off, should turn on test light. This test checks capability of ECM to supply a ground to the TCC solenoid. Test light will light when connected from 12 volts to ALDL terminal "F" as circuit No. 422 is grounded.