Torque Converter Diagnosis

Torque Converter Diagnosis
Prior to installing a new or remanufactured torque converter, all diagnostic procedures must be followed. This is to prevent the unnecessary installation of new or remanufactured torque converters. Only after a complete diagnostic evaluation can the decision be made to install a new or remanufactured torque converter.

Begin with the normal diagnostic procedures as follows:
1. Preliminary Inspection.
2. Know and Understand the Customers Concern.
3. Verify the Concern - Carry out the Torque Converter Operation Test.
4. Carry out Diagnostic Procedures.
^ Carry out On-Board Diagnostics. Refer to Computers and Control Systems.
- Repair all non-transmission related DTCs first.
- Repair all transmission DTCs.
- Rerun on-board diagnostics to verify repair.
^ Carry out Line Pressure Test. Line Pressure Test
^ Carry out Stall Speed Test. Stall Speed Test
^ Carry out Diagnosis by Symptom Routines. Refer to Diagnosis By Symptom. CD4E Automatic Transmission
^ 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 correctly. Carry out the test as follows:
1. Carry out On-Board Diagnostic Test. Refer to Computers and Control Systems.
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 5 seconds after the brake pedal is released. If this does not occur, see Torque Converter Operation Concerns. Refer to Diagnosis By Symptom. CD4E Automatic Transmission
If the vehicle is at a stop and stalls in (D) at idle, move the transaxle range selector lever to the manual 1 position, see Torque Converter Operation Concerns. Refer to Diagnosis By Symptom. CD4E Automatic Transmission
Repair as required. If the vehicle does not stall in manual 1, refer to Diagnosis By Symptom. CD4E Automatic Transmission