Chart C8 - Torque Converter Clutch: Notes

The TCC will engage when the engine is warmed up, vehicle speed is greater than about 32 MPH, throttle sensor output is not changing (indicating a steady road speed), 3rd gear switch is closed and the brake switch is closed. An engine coolant thermostat that is stuck open, or opens at too low a temperature, may result in an inoperative TCC.

1. When test light is off, this confirms 3rd gear switch is open.
2. At 25 MPH the 2nd gear switch should close. Test light will come on and confirm battery supply and closed brake switch.
3. Grounding the ALDL "test" terminal with ignition on and engine off, should energize the TCC solenoid by grounding circuit No. 422. This test checks the capability of the ECM to supply a ground for the TCC solenoid. Test light should turn on as circuit No. 422 is Grounded.