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P0743 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

The P0743 error code indicates that the powertrain control module has identified an issue with the torque converter clutch circuit.

Meaning

The diagnostic trouble code (DTC) P0743 means "Torque Converter Clutch Solenoid Circuit Electrical." It identifies a possible problem with the torque converter clutch solenoid (TCC) or its circuit.

Causes

  • The torque converter clutch solenoid is faulty   
  • Torque converter not working
  • Failure of a mechanical internal transmission
  • A blockage in the transmission fluid passages caused by hydraulic pressure
  • The transmission fluid level is low
  • Transmission fluid that is dirty
  • A faulty PCM or transmission control module

Symptoms

This code is associated with a wide range of symptoms. Drivers might not realize there is any problem behind the wheel in some cases. It may also stall after they've stopped and the engine is still idling, indicating an issue with the engine. For instance, this can happen at a stop sign or stop light. In addition, there are symptoms such as difficulty shifting, slipping transmissions, and a burning transmission. Furthermore, this code will often cause the Check Engine light to illuminate.

Diagnosis

The mechanic will first connect the onboard computer of the vehicle to their OBD-II scanner before diagnosing the P0743 code. Data and trouble codes will be stored in the onboard computer. The scanner verifies the data. The mechanic then wants to drive the car again after resetting the trouble code. By doing this, they can check if the code is returned. If it does, it did not get set by mistake. If that is not the case, then they can continue with the diagnosis to find out what caused the code P0743.

Common mistakes

Some technicians have discovered that mechanics often replace lock up solenoids and torque converters when they don't need to. They've overlooked a simpler issue, namely, faulty wiring that affects the torque converter.

How serious is this?

A vehicle with the P0743 code will have issues when it comes to shifting, and the transmission may overheat, which could lead to other problems.The vehicle may also stall when it reaches a stop sign or stoplight. In some cases, it may even be dangerous. Even when the driver doesn't notice anything wrong with the vehicle, I highly recommend bringing it to a mechanic if the P0743 code was stored.

What repairs can fix the code?

  • The mechanic will ascertain that the trouble code is a legitimate one by resetting, driving the car, and seeing if it comes back. The mechanic will then conduct a wiring and connection check to ensure that everything is connected correctly and no problems exist.
  • A mechanic will also check the condition of the transmission fluid, including whether it is dirty or contaminated.
  • Transmission fluid passages are checked for blockages by the mechanic
  • The torque converter clutch solenoid or torque converter may need to be replaced
  • The transmission control module may need to be replaced in rare cases

Related codes

None listed.

Conclusion

The P0743 code can be a dangerous code. No matter whether the driver notices any problems while driving the vehicle, if it has been stored it is always best to have the vehicle serviced by a mechanic.  The P0743 code is not always noticeable, but it can lead to serious problems.