Component Tests

Torque Converter Diagnosis
Prior to torque converter replacement, all diagnostic procedures must he followed. This is to prevent the unnecessary replacement of good torque converters. Only after a complete diagnostic evaluation can the decision be made to replace the torque converter.
Begin with the normal diagnostic procedures as follows:
1. Preliminary Inspection
2. Know and Understand the Customers Concern.
3. Verify the Concern
- Perform the Torque Converter Clutch Operation Test.

4. Perform Diagnostic Procedures
- Run On-Board Diagnostics.
- Repair all non-transmission related DTCs first.
- Repair all transmission DTCs.
- Rerun on-board diagnostics to verify repair.
- Perform Line Pressure Test.
- Perform Stall Speed Test.
- Perform Diagnosis by Symptom Routines. Refer to Diagnosis by Symptom.
- Use the index to locate the appropriate routine that best describes the symptom(s). The routine will list all possible components that may cause or contribute to the symptom. Check each component listed, diagnose, and repair as required, before repairing the torque converter.

Torque Converter Clutch Operation Test
This test verifies that the torque converter clutch control system and the torque converter are operating properly. Perform the test as follows:
1. Perform on-board diagnostic test. Refer to appropriate pinpoint test or procedure 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 D position.
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 should decrease about five seconds after the brake pedal is released. If this does not occur, refer to torque converter operation concerns. Refer to Torque Converter Operation Concerns in the Diagnosis by Symptom charts.
6. If the vehicle is at a stop and stalls in D at idle, move the transaxle range selector lever to the manual 1 position. Refer to Torque Converter Operation Concerns in the Diagnosis by Symptom charts. Repair as required. If the vehicle does not stall in manual 1, refer to the procedure. Refer to Torque Converter Operation Concerns in the Diagnosis by Symptom charts.