Torque Converter Clutch Operation Tests

Torque Converter Clutch Operation Tests

This test verifies that the Torque Converter Clutch Control System and torque converter are operating properly.

1. Perform On-Board Diagnostic Tests. Check for a code 628, 652 or 656. Refer to the pinpoint test for diagnosis.
2. Connect a tachometer to the engine.
3. Bring engine to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes in O/D range.
4. After normal operating temperatures are reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap the brake pedal with the left foot.
5. Engine rpm should increase when the brake pedal is tapped and decrease about five seconds after the brake pedal is released. If this does not occur, refer to Torque Converter Operation Concerns in the Diagnosis by Symptom Charts.
6. If the vehicle stalls in O/D at idle with the vehicle at a stop, move the manual lever to the Manual 1 position. If the vehicle stalls, the cause may be the converter control valve in the pump assembly. Service as required. If the vehicle doesn't stall in Manual 1, refer to Pinpoint Test C.