Fixing P0743: Torque Converter Clutch Circuit Stuck On

Is your check engine light on? Are you experiencing transmission issues and reduced fuel efficiency? If so, you might be dealing with a P0743 code, indicating a problem with the Torque Converter Clutch (TCC) circuit.

But don’t worry, we’re here to help you fix it. In this article, we’ll provide you with step-by-step instructions and useful tips to address the issue at hand and get your vehicle back on the road. So let’s dive in and tackle the P0743 code together.

Understanding the Torque Converter Clutch (TCC)

Before we delve into the details of fixing the P0743 code, let’s take a moment to understand the Torque Converter Clutch and its significance in automatic transmissions. The Torque Converter Clutch is a vital component that helps improve fuel efficiency and reduce transmission slippage.

The TCC is responsible for mechanically connecting the engine to the transmission, allowing for direct power transfer without the slippage typically associated with fluid coupling. By engaging and disengaging the TCC, the transmission can optimize the power transfer between the engine and the wheels, enhancing overall performance.

car vertical

Symptoms of a P0743 Code

When the Torque Converter Clutch circuit gets stuck on, it triggers the P0743 code and manifests in various symptoms. Recognizing these signs can help you diagnose the issue accurately. Here are the common symptoms associated with a P0743 code:

  1. Check Engine Light: The illuminated check engine light is often the first indication of a problem. It serves as a general warning that something requires attention within the vehicle’s systems.
  2. Transmission Slipping: You may notice that the transmission slips or shifts inconsistently. This could result in delayed engagement or abrupt gear changes.
  3. Poor Fuel Efficiency: A malfunctioning TCC can affect fuel efficiency by causing excessive slippage or preventing the lock-up engagement. Reduced fuel economy is a common side effect.

Diagnosing the P0743 Code

To accurately diagnose the P0743 code, you’ll need an OBD-II scanner, which can read the diagnostic trouble codes stored in your vehicle’s computer system. Follow these steps to diagnose the issue:

  1. Using an OBD-II Scanner: Connect the scanner to the OBD-II port, typically located under the dashboard. Retrieve the trouble codes and write down any additional codes present.
  2. Inspecting the Wiring and Connections: Visually inspect the wiring and connections related to the TCC circuit. Look for loose connections, frayed wires, or signs of damage. Repair or replace any faulty components as necessary.
  3. Testing the Torque Converter Clutch Solenoid: The Torque Converter Clutch solenoid is a common culprit for the P0743 code. Test the solenoid’s resistance using a multimeter to ensure it falls within the manufacturer’s specifications. Replace the solenoid if the resistance is out of range.

Steps to Fix P0743: Torque Converter Clutch Circuit Stuck On

Now that you’ve diagnosed the P0743 code and identified the underlying issue, it’s time to fix it. Follow these step-by-step instructions to address the problem effectively:

Step 1: Prepare the necessary tools and materials

Gather the tools and materials you’ll need for the repair, including a socket set, wrenches, a multimeter, a new Torque Converter Clutch solenoid (if required), and a drain pan.

Step 2: Lift and secure the vehicle

Use a jack to lift the vehicle off the ground and secure it with jack stands. Ensure the vehicle is stable and won’t shift during the repair process.

Step 3: Locate the torque converter clutch solenoid

Refer to your vehicle’s service manual to locate the Torque Converter Clutch solenoid. It is typically mounted on the transmission case or valve body.

Step 4: Remove the electrical connector and solenoid

Disconnect the electrical connector from the solenoid by gently pulling it away. Then, remove the solenoid by unscrewing the bolts or retaining clips holding it in place.

Step 5: Inspect the solenoid for debris or damage

Examine the solenoid for any debris, dirt, or signs of damage. Clean the solenoid using an appropriate cleaning agent and a lint-free cloth. If the solenoid is damaged, it will need to be replaced.

Step 6: Clean or replace the solenoid if necessary

If the solenoid is dirty, use a cleaning agent to remove any residue. Make sure it is thoroughly dry before reinstalling. If the solenoid is damaged or fails the resistance test, replace it with a new one.

Step 7: Reinstall the solenoid and reconnect the electrical connector

Secure the new or cleaned solenoid back into position using the appropriate bolts or retaining clips. Reconnect the electrical connector to ensure a proper connection.

Step 8: Lower the vehicle and test drive

Carefully lower the vehicle from the jack stands and take it for a test drive. Monitor the transmission’s behavior and ensure that the P0743 code is no longer present. If everything appears normal, you have successfully fixed the issue.

Tips for Successful Repair

To ensure a successful repair process and prevent future problems, consider the following tips:

  • Always follow safety precautions: When working under a vehicle, prioritize safety by using jack stands and following proper lifting procedures.
  • Use manufacturer-approved replacement parts: Use genuine or high-quality replacement parts recommended by the vehicle’s manufacturer to ensure compatibility and reliability.
  • Double-check connections and wiring: Before completing the repair, verify that all connections and wiring are secure and properly installed.

By following these tips, you can improve your chances of a successful repair and avoid potential setbacks.


Fixing the P0743 code related to the Torque Converter Clutch Circuit Stuck On is a task that requires proper diagnosis and careful execution. By understanding the symptoms, diagnosing the issue, and following the step-by-step repair instructions provided in this article, you can confidently address the problem and restore the optimal functioning of your vehicle’s transmission.

Remember to prioritize safety and use the recommended tools and parts throughout the repair process. If you’re unsure about any step or lack the necessary skills and experience, it’s always advisable to seek professional assistance from a qualified mechanic.

Now that you have the knowledge and guidance, go ahead and tackle the P0743 code with confidence. Your car will thank you for it!

FAQs (Frequently Asked Questions)

1. How much does it cost to fix the P0743 code?

The cost of fixing the P0743 code can vary depending on factors such as the make and model of your vehicle, labor rates in your area, and whether you choose to do the repair yourself or seek professional help. It’s best to consult with a mechanic or get a repair estimate from a trusted service center for a more accurate cost assessment.

2. Can I still drive my car with a P0743 code?

Continuing to drive your car with a P0743 code is not recommended. The code indicates a malfunction in the Torque Converter Clutch circuit, which can lead to transmission issues and reduced fuel efficiency. It’s important to address the problem promptly to prevent further damage and potential safety risks.

3. Can I fix the P0743 code myself, or should I take it to a mechanic?

The ability to fix the P0743 code yourself depends on your skills, experience, and access to the necessary tools. If you’re confident in your abilities and have the required knowledge, you can attempt the repair following the provided instructions. However, if you’re unsure or lack the necessary expertise, it’s advisable to seek professional help from a qualified mechanic to ensure a proper and safe repair.