Fix P0740 OBD2 Codes: Clutch Switch Input Circuit Malfunction

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The error code P0740 OBD II is technically taken as a defect in the Torque Converter Clutch Circuit. The main cause of this code has defected Torque Converter but sometimes fluid or transmission is also the reason behind it.

What exactly P0740 OBD II Code means?

There is a torque converter clutch circuit in the vehicle that communicates with the powertrain control module. The power control module changes the torque converter clutch used to optimize the performance of the vehicle. The P0740 code will trigger if the powertrain control module feels that the torque converter clutch circuit is not working properly.

The check engine light of the vehicle will be illuminated by the powertrain control module for the alert. Automatic cars have a system where power is transmitted from engine to transmission and a converter is used for this purpose. The fluids in the torque converter help the engine to perform successfully.

The real causes of the P0740 OBD II code

The causes that result in code P0740 OBD II are the following:

  • The torque converter clutch solenoid of the vehicle defects.
  • The fluid levels transmission is having some issues.
  • The transmission is damaged from the internal side.
  • The transmission module is defective.
  • Skipping maintenance of the transmission for a long time. 
  • Filters and filters did not change for a long time.

Symptoms of P0740 OBD II code

The code P0740 shows various symptoms that are below:

  • The vehicle starts to stall.
  • The transmission is not shifting while the gear is put.
  • The transmission is getting rough.
  • There is overheating issue in the transmission.
  • The torque converter is causing issues and the vehicle is not able to move.
  • The check engine light starts to illuminate.
  • The fuel economy will decrease resulting in less fuel mileage.

Diagnose and fix Code P0740 OBD II

Diagnose p0740

Tools to fix P0740 Code

  1. Obd2 Scanner

How to start diagnoses Tools to fix P0740 Code OBD II

If you are looking to fix the code P0740 yourself then remember that it is difficult to deal with. The repairing manual can also help you to understand the issue and ways to deal with it. As different vehicles have different kinds of approaches to even deal with some kind of problem. Here are the diagnosis steps that can help you to fix the code issue. 

Visual inspection

The first step is to inspect the car visually to find out the real problem reason. It is the most important step in vehicle repair. A professional mechanic can point out my problems just by digging deep into the visual inspection.  

Check the Fluids Level

The most common cause is the fluid area so have a look at the fluid level first. If the fluid level is less then maintain it properly. Sometimes maintaining the fluid level alone will resolve the issue completely. Also, ensure that the fluid is not dirty or destroyed. The real fluid is shown as a cranberry juice clear and flowing. If you feel that color and flowing levels are not the way they should be then changing it would also help for the vehicle. 


It’s time to get to the scanning part by connecting the scanner with your vehicle and seeing the trouble code. Remember that remember the code alone will not remove the issue from the vehicle.  

Advanced measures

A professional mechanic will look closely at the fluid, filters, transmission, as well as torque converter, and clutch circuit part to examine where exactly the problem lies. The wiring of the vehicle should also be checked to ensure a successful fix. 

Common Code P0740 OBD II Diagnosis Mistakes

The most common mistake when looking to fix the P0740 code is just directly replacing the torque converter. The proper examination is required before jumping to repair the torque converter. Sometimes the real root cause is the fluid area. The fluid level needs to be checked before replacing any part. It will save a lot of your money.     

Replace/Repair These Parts to Fix OBD Code P0740 OBD II

Replacing some parts will help you to deal with this issue perfectly. They are the following:

  • Torque Converter: Most of the time the root cause of the P0740 code is the torque converter so replacing it with the new one will resolve the issue. 
  • Transmission: If you see that the transmission is not working the way it should then replace it with a new one. 
  • Fluid and Filter: If for a long time the transmission fluid and filter were not given attention then it is time to do it. Old fluid and filter might be the reason for P0740 code occurrence.

Cost related to P0740 code OBD II Repair

The cost entirely depends upon the level of the issue a torque converter can cost around $100 to $300 while the transmission wire repair will be just $50.

The severity of P0740 code OBD II

The P0740 code is a very serious one to consider for. This is the issue that can make you stand at the side of the road and imagine if it is midnight. You would never like to face issues so better consider them at the right time. 

Other Codes related to P0740 code OBD II

The other code that is related to P0740 is P0700 and it shows the malfunction in the transmission control system. The other related codes are P2770, P0744, P2769, P0742, P0741, and P0743 and they all point to the clutch circuit issues. 

Tips to avoid P0740 code OBD II

The best tip to avoid from the P0740 code is that change the transmission fluid and filters from time to time depending upon the interval described for the vehicle. This will keep the parts well lubricated and you will not face such issues. Learn about the interval time of fluids and filter changing.    


Like a machine, your vehicle can show the P0740 code issue at any time but keeping it up to date by visiting your nearest mechanic will prevent you from future hassle.

WARNING, Do not replace the Torque Convertor Clutch Solenoid for P0740 in the 62TE. Here's why.
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