For 1990-2009 cars

### Torque Converter Clutch (TCC) Diagnosis

In order to properly diagnose the Torque Converter Clutch (TCC) system, perform all electrical testing first. Then perform the hydraulic testing.

The Torque Converter Clutch (TCC) is applied by fluid pressure, which is controlled by a solenoid valve. This solenoid valve is located inside of the automatic transmission assembly.

The vehicle PCM energizes the solenoid valve.

### Functional Check Procedure

1. Set up the TECH 1 or other scan tool in order to read the engine.
2. Operate the vehicle until you have reached the proper operating temperature.
3. Drive the vehicle at 80-88 km/h (50-55 mph) with a light throttle (road load).
4. Maintaining throttle speed, lightly touch the brake pedal. Check for the release of the TCC and a slight increase in engine speed.
5. Release the brake and slowly accelerate. Check for a reapply of the converter clutch and a slight decrease in engine speed.
6. To properly diagnose the Torque Converter Clutch (TCC) system, first perform all electrical testing and then test the hydraulic system.

• | For diagnosis of the TCC hydraulic controls, refer to the Fluid Flow and Circuit Descriptions, and the Wiring Diagrams.

• | Refer to the DTC tables.

### Torque Converter Stator

The torque converter stator roller clutch can have two different malfunctions.

• | The stator assembly freewheels in both directions.

• | The stator assembly remains locked up at all times.

### Poor Acceleration at Low Speed

If the stator is freewheeling at all times, the car tends to have poor acceleration from a standstill. At speeds above 50-55 km/h (30-35 mph), the car may act normally. For poor acceleration, you should first determine that the exhaust system is not blocked, and the transmission is in First gear when starting out.

If the engine freely accelerates to high RPM in Neutral, you can assume that the engine and the exhaust system are normal. Check for poor performance in Overdrive and Reverse to help determine if the stator is freewheeling at all times.

### Poor Acceleration at High Speed

If the stator is locked up at all times, performance is normal when accelerating from a standstill. Engine RPM and car speed are limited or restricted at high speeds. Visual examination of the converter may reveal a blue color from overheating.

If the converter has been removed, you can check the stator roller clutch by inserting two fingers into the splined inner race of the roller clutch and trying to turn the race in both directions. You should be able to freely turn the inner race clockwise, but you should be unable to move the race at all in a counterclockwise direction.

### Noise

Important: Do not confuse this noise with pump whine noise, which is usually noticeable in Park, Neutral, and all other gear ranges. Pump whine will vary with line pressure.

You may notice a torque converter whine when the vehicle is stopped and the transaxle is in Drive or Reverse. This noise will increase as you increase the engine RPM. The noise will stop when the vehicle is moving or when you apply the torque converter clutch, because both halves of the converter are turning at the same speed.

Perform a stall test to make sure the noise is actually coming from the converter:

1. Place your foot on the brake
2. Put the gear selector in Overdrive

Notice: You may damage the transmission if you depress the accelerator for more than 6 seconds.

3. Depress the accelerator to approximately 1200 RPM for no more than six seconds

A torque converter noise will increase under this load.

### Replace the Torque Converter

Replace the torque converter under any of the following conditions:

• | External leaks appear in the hub weld area

• | The converter hub is scored or damaged

• | The converter pilot is broken, damaged, or fits poorly into the crankshaft

• | You discover steel particles after flushing the cooler and the cooler lines

• | The pump is damaged, or you discover steel particles in the converter

• | The vehicle has TCC shudder and/or no TCC apply. Replace the torque converter only after all hydraulic and electrical diagnoses have been made. The converter clutch material may be glazed.

• | The converter has an imbalance which cannot be corrected. Refer to the Flexplate/Torque Converter Vibration Test Procedure later in this section.

• | The converter is contaminated with engine coolant which contains antifreeze

• | An internal failure occurs in the stator roller clutch

• | You notice excessive end play

• | Overheating produces heavy debris in the clutch

• | You discover steel particles or clutch lining material in the fluid filter or on the magnet, when no internal parts in the unit are worn or damaged. This condition indicates that lining material came from the converter.

### Do Not Replace the Torque Converter

Do not replace the torque converter if you discover any of the following symptoms:

• | The oil has an odor or the oil is discolored, even though metal or clutch facing particles are not present.

• | The threads in one or more of the converter bolt holds are damaged. Correct the condition with a thread insert. Refer to the Engine Mechanical section.

• | Transmission failure did not display evidence of damaged or worn internal parts, steel particles or clutch plate lining material in the unit and inside the fluid filter.

| The vehicle has been exposed to high mileage only. An exception may exist where the lining of the torque converter clutch dampener plate has seen excess wear by vehicles operated in heavy and/or constant traffic, such as taxi, delivery, or police use.