P0744 OBD-II Trouble Code: Torque Converter Clutch Circuit Intermittent

P0744 code definition

If the PCM has stored the P0744 code, it means that there was an intermittent abnormality detected in the torque converter clutch circuit.

What the P0744 code means

If the automatic transmission needs a specific amount torque converter “lock up”, and the actual amount of lock up detected does not coincide with the necessary amount, the system will assume that the torque converter clutch circuit is malfunctioning, and will direct the PCM to store the P0744 code.

What causes the P0744 code?

The P0744 code may be stored if the torque converter clutch solenoid is faulty, or if the torque converter is defective. Other causes may include:

• Blocked internal transmission fluid passages
• Mechanical internal transmission failure
• Low transmission fluid
• Open or shorted torque converter clutch solenoid valve harness
• Poor electrical connection in the torque converter clutch solenoid valve circuit
• Dirty transmission fluid
• A faulty transmission control module, or TCM

What are the symptoms of the P0744 code?

The symptoms of the P0744 code can vary. There may be no detectable symptoms at all beyond the illumination of the Check Engine Light. However, symptoms could be as dire as the total failure of the torque converter clutch to disengage. Other symptoms may include:

• Harsh shifting
• Transmission overheating
• Transmission slippage
• Decreased fuel efficiency

How does a mechanic diagnose the P0744 code?

After an OBD-II scanner detects the P0744 code, a technician should begin with a visual inspection of the transmission fluid levels and condition. One of the most common reasons for this code is debris obstructing the flow of transmission fluid throughout the transmission valve. The mechanic should change dirty transmission fluid, and ensure that the fluid does not have a burnt smell, or lacks the proper pressure.

After the transmission fluid has been thoroughly checked and replaced, the code should be cleared from the PCM, and the system should be retested. If the code returns, the mechanic can continue on to further repairs.

Common mistakes when diagnosing the P0744 code

The most common misdiagnosis when the P0744 code is detected is that of overlooking malfunctions in the torque converter clutch wiring. Many technicians replace lock up solenoids or torque converters in error, without considering the potential wiring issues.

It is also important to clear the P0744 code and retest the system after each repair is attempted. If the initial, simple repairs do not stop the Check Engine Light from reappearing and the code from being re-stored in the PCM, it can be a sign of an intermittent issue that requires an in-depth inspection and servicing.

How serious is the P0744 code?

If the P0744 code is detected by the OBD-II scanner, it represents a very serious issue that should not be put off. Issues within the transmission can quickly lead to total transmission failure, and can cause a vehicle to perform less than optimally. If the P0744 is detected, the issue should be addressed right away.

What repairs can fix the P0744 code?

There are many ways that a technician can address a P0744 code, including:

• Checking and replacing transmission fluid; if the fluid is found to be very dirty, flushing the system and replacing the torque converter may be required.
• Checking and replacing any shorted or faulty wiring, connectors, and circuitry.
• Replacing the internal transmission harness.
• Finding and repairing any leaks in transmission fluid.
• Replacing a defective pump.
• Repairing or replacing open or shorted torque converter clutch solenoid valve harness.
• Rebuilding or replacing the transmission.
• Repairing or replacing a faulty TCM or PCM in rare cases.

Need help with a P0744 code?

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