P1749 – OBD-II DTC

OBD-II DTC P1749 – Torque Converter Clutch System Performance

DTC P1749 meaning

DTC P1749 refers to a diagnostic trouble code that indicates a problem with the Torque Converter Clutch (TCC) system performance. The TCC is responsible for locking the torque converter to improve fuel efficiency and reduce engine load during cruising conditions. When the vehicle’s onboard diagnostics detect that the TCC is not functioning as expected, this code is triggered.

DTC P1749 symptoms

Common symptoms associated with DTC P1749 may include:

• Engine stalling or hesitation during acceleration
• Increased engine RPMs while driving
• Poor fuel economy
• Transmission slipping or harsh shifting
• Illuminated check engine light

DTC P1749 causes

Several factors can lead to the triggering of DTC P1749, including:

• Faulty torque converter clutch solenoid
• Wiring issues or poor connections in the TCC circuit
• Low transmission fluid levels or dirty fluid
• Faulty transmission control module (TCM)
• Mechanical issues within the transmission

DTC P1749 seriousness

DTC P1749 can be considered a moderate to serious issue. While it may not cause immediate vehicle failure, it can lead to poor performance, reduced fuel efficiency, and potential damage to the transmission if left unaddressed. It is advisable to diagnose and repair the issue promptly to avoid further complications.

How to diagnose DTC P1749

To diagnose DTC P1749, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1749 code.
2. Check for any additional trouble codes that may provide more context.
3. Inspect the transmission fluid level and condition.
4. Examine the TCC solenoid and its wiring for damage or disconnection.
5. Test the TCC solenoid operation using a multimeter.
6. Check the transmission control module for faults.
7. Perform a road test to observe the vehicle’s behavior under various conditions.

How to fix DTC P1749 step-by-step instructions

To fix DTC P1749, follow these steps:

1. Address any low or dirty transmission fluid by performing a fluid change and refill.
2. Replace the faulty torque converter clutch solenoid if testing indicates it is defective.
3. Repair or replace any damaged wiring or connectors in the TCC circuit.
4. Reprogram or replace the transmission control module if necessary.
5. Clear the DTC using an OBD-II scanner.
6. Perform a road test to ensure the issue is resolved and the code does not return.

How to erase DTC P1749

To erase DTC P1749, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear Codes” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the vehicle to verify that the code does not reappear.

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