Chart C-8A, Torque Converter Clutch Electrical Diagnosis - 2.5L TBI A & N Bodies: Notes

Fig 1: Chart C-8A, TCC Circuit (2.5L A & N Bodies)

Courtesy of GENERAL MOTORS CORP.

Voltage is supplied to TCC solenoid through brake switch and transaxle third 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 with air conditioning off, or above 44 MPH with air conditioning on.
• Engine is at normal operating temperature.
• Throttle position not changing, indicating a steady speed.
• Brake switch and transmission 3rd gear switch are closed.
  NOTE: Test numbers refer to test numbers in diagnostic chart.
  1. Light off confirms transmission 3rd gear apply switch is open.
  2. At approximately 30 MPH, transmission 3rd gear switch should close. This depends on throttle position. Minimum speed at which 3rd gear switch will closed is approximately 21 MPH. Test light should light and confirm ignition voltage in circuit and a 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 control the solenoid.