Torque Converter Operation Test

Torque Converter Operation Test

NOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.

The Torque Converter Operation Test verifies that the Torque Converter Clutch (TCC) control system and the torque converter are operating correctly.

1. Perform a Self Test with the scan tool. Refer to Computers and Control Systems, Testing and Inspection. Check for DTCs.

2. Connect a scan tool to the vehicle.

3. Bring the engine to normal operating temperature by driving the vehicle at highway speeds in the (D) position.

4. After normal operating temperature is reached, maintain a constant speed of about 56 km/h (35 mph) in 5th gear for 10 seconds.

5. Release the accelerator pedal and monitor the scan tool Throttle Position (TP) voltage to approximately 1.25 volts or 25% throttle.

6. Monitor the TCC and RPM TCM PID. The TCC should release and engine rpms should increase before the 5-4 shift occurs.

NOTE: The following is a list of common vehicle concerns that have been misdiagnosed as TCC shudder. For diagnosis of the following items, refer to the appropriate vehicle system.

- Spark plugs - check for cracks, high resistance or broken insulators
- Ignition coil-on-plug - misfire
- Fuel injector - filter may be plugged
- Fuel contamination - engine driveability concerns
- EGR valve - valve may let in too much exhaust gas and cause engine to run lean
- Vacuum leak - engine will not get correct air/fuel mixture
- Manifold Absolute Pressure (MAP) and Mass Air Flow (MAF) sensor - incorrect air/fuel mixture
- Heated Oxygen Sensor (HO2S) - too rich/lean air/fuel mixture
- Fuel pressure - may be too low
- Engine mounts - loose/damaged mounts can cause vibration concerns
- Axle joints - check for vibration