torque converter bench

P0740 Code: Torque Converter Clutch Circuit Malfunction

In OBD2 Trouble Codes by Magnus Sellén16 Comments

Do you have problems with the P0740 error code?

In this article we will discuss what this error code means and how you can find the problems to fix them.

We start with the meaning of the P0740 error code and possible symptoms.

What Does the P0740 Code Mean?

Code P0740 indicates that the Powertrain Control Module (PCM) has observed unusual behavior within the torque converter clutch circuit.

Torque converter

Any vehicle built since 1996 will return this common fault code if a problem is detected with the torque converter clutch circuit. However, modern vehicles today determine when this code must be given based on other information such as throttle position, engine load, vehicle speed, etc.

P0740 Symptoms

Initially, you will not notice any symptoms if a problem occurs with the torque converter clutch. However, if the problem persists and is ignored for a long time, your converter clutch may fail completely and also disrupt engine performance. Common symptoms include:

  • Check engine light illuminates
  • Fall in fuel economy
  • Torque converter clutch fails to engage
  • Trouble when shifting gears
  • Transmission overheating
  • Engine stalling
  • Transmission gets stuck in a single gear
  • Car fails to move when in gear
  • Engine misfire

Possible P0740 Causes

Error code P0740 can be triggered for many reasons. Among the most common causes are:

  • Damaged torque converter lockup solenoid
  • Defective torque converter or clutch
  • Internal damage within the transmission
  • Faulty valve body
  • Low transmission fluid level
  • Non-functioning engine coolant temperature sensor
  • Damaged wiring

Possible P0740 Solutions

The first step should be to check the wiring and connection of the torque converter clutch leading to the PCM. Most of the time, it’s all about the wiring and the bad connection, while the mechanics will take your money by claiming a huge problem. If the problem is not related to the wiring, look for the following solutions:

  • Repair and replace the torque converter clutch solenoid
  • Replace torque converter clutch
  • Check and replace transmission fluid
  • Repair powertrain control module
  • Replace the transmission system
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Problem Symptoms Causes Solutions
P0740 Trouble Code Check engine light illuminates

Drop in Fuel Economy

Torque Converter Clutch fails to engage

Trouble when shifting Gears

Transmission overheating

Engine Stalling

Transmission gets stuck in a single gear

Car fails to move when in gear
Damaged Torque Converter Lockup Solenoid

Defective Torque Converter or Clutch

Internal Damage within the Transmission

Faulty Valve Body

Low Transmission Fluid Level

Damaged Wiring
Repair and replace the Torque Converter Clutch solenoid

Replace Torque Converter Clutch

Check and replace transmission fluid

Repair powertrain control module

Replace the transmission system

How to Diagnose the P0740 Code?

The P0740 code can be a little difficult to diagnose at first, but can be observed when the car has driveability problems. You will need to have a factory wiring diagram of your car to find the correct connection points between the circuitry and detect wiring damage. You should also check the transmission oil.

Here are some steps you should follow to diagnose the P0740 code.

Connect a Car Battery Charger

It is important that your vehicle’s battery does not discharge while you are working on troubleshooting the error codes. It is therefore important that you attach a car battery charger when working on your vehicle with the ignition on. In addition, a weak battery can also generate additional fault codes, which makes the situation even more confusing.

Connect the OBD2 Scanner

To read the information generated by the error codes an OBD2 Code Scanner is required. This device allows you to easily read the data from the error code and also has built-in values that you can use to make a comparison and determine the cause of the problem. You will also need a digital volt-ohm meter to test the circuit resistance.

Check the Wire Connections

The most important first step is to determine whether a bad connection or wiring is causing the P0740 error code to be generated. Examine the wiring leading to the transmission system and look for signs of damage. Refer to the vehicle’s factory wiring diagram for easy identification of all connection points.

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Check Transmission Fluid

If you have checked the wiring and the connections leading to the transmission system and everything seems to be in order, check the transmission oil for its correct level and condition. If the fluid appears to be less or different to the norm, this may be part of the problem.

Check Resistance of TCC Solenoid

First remove the connector of the transmission system wiring harness and then check the resistance of the TCC magnet with the DVOM. If the displayed resistance is too high, there may be something wrong with the solenoid coil.

Testing TCM

TCM can be monitored with an advanced diagnostic tool, and it requires some expertise to understand the reading. It is advisable to take your car to an automotive specialist who will perform this test and let you know if the problem is related to TCM.

Transmission Torque Converter Clutch Solenoid Replacement

In most vehicles, the transmission solenoid valve is located in the oil sump and is connected to the valve body. In such a case, a car expert can easily replace the damaged switching solenoid. However, on some vehicles, the transmission solenoid valve is packed in several units, and if a problem occurs, the entire package must be replaced.

The average cost of replacing a single transmission solenoid is between $20 and $100, and an entire package can cost about $200. Labor costs are about $150 to $400.

Does the P0740 Code Need Serious Attention?

The engine is not the only thing that powers the vehicle. The transmission system is equally important, and any problem with the transmission system can leave you stuck in the middle of the road. If you notice early symptoms of the P0740 code, it is advisable to follow the above guidelines and diagnose the problem or take your car to a car specialist. If the code persists and is not heeded, the transmission system may fail and also damage the engine. For this reason, the P0740 code should be dealt with as soon as possible.

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How to Avoid the P0740 Code?

If the P0740 code is ignored for a long period of time, it can cause serious problems with the driving performance and damage other components in addition to the gearbox. You can avoid this problem by checking and replacing the transmission oil and filter regularly (or at regular intervals). This will ensure that the components inside the transmission system remain well lubricated and operate at maximum efficiency.

Further Questions?

If you have any further questions about the P0740 code, simply contact us via the comments below and I will contact you as soon as possible.

16 thoughts on “ P0740 Code: Torque Converter Clutch Circuit Malfunction ”

Comments
  1. I’m getting the p0740 code, this is what my truck is doing….back out driveway fine ,put in gear truck sits there, maybe 30 seconds, finally goes in gear , drives 100 yards it disengages again, coast for 100 yards, then it engages for 100 yards, then it disengages again over and over…HELP

    1. Author

      It sounds like a problem with a shift solenoid or the shift stick. Check with a scanner and see the live data if the Transmission control unit is getting the “Drive” signal from the stick.

    2. Sounds like control module, mine did the same, replaced it and let it circulate, got up and went, there are kits for them, never worked on one so don’t know how extensive It would be

  2. Have a 20111 Chrysler Town and Country Limited, 3.6L flex fuel engine; 62 TE 6 speed transmission; 74,500 miles. Got the P0740 fault. Tranny shifts perfectly , both automatically and “manually”. Dropped both bottom and front pans, replaced atf fluid with Valvoline+4 synthetic fluid and replaced the TCC solenoid.

    Old fluid didn’t have any metal parts, not thick and black and ugly. Checked wiring for broken, frayed wires didn’t see any. I erase the fault but it keeps coming back. Again, tranny shifts perfectly, both automatically and “manually”. It does go in to 6th gear, i see the tach go down a bit when it does. and stays there. Took to Chrysler dealer they checked and “think it is the torque converter. But agree they are not sure that IS THE Problem. Any ideas, please?

    1. I have a 2011 Town and Country too! I did exactly what you did and my light keeps coming back on too. Did you ever resolve this? Thank you

    2. Any luck and resolution with your Chrysler Town and Country P0740 fault? Thank you

  3. So, the P0740 code came on in my son’s 2001 Jeep Wrangler (4.0l, 3 speed auto trans, 4wd). Had the trans overhauled, new filter, fluid, valve body, new torque converter). 100 miles later, the check engine light returned the same code? What else is there to repair?

    1. HI Chris. I too have a P0740 code that comes on and goes away on exactly the same 01, Jeep Wrangler three speed auto. Did any one reply to your question?

  4. I have a 2004 Honda crv when you put it in gear it goes in and out of drive and when you move it it sometimes pops out of gear it has a flashing D light on trouble codes are PO780 and PO740 I replaced all the solenoids pressure sensors and speed sensors and it still does the same thing have any suggestions

  5. 2013 chrysler town and country code p0740 car is high idling and stalls sometimes when slowed down

    1. We have a 2013 as well, and the code popped up 2 days agao. Did you get your situation resolved, and if so how? Thanks in advance.

  6. My 2017 2ss Camaro was hesitating then “grabbing,” it also started vibrating (seemed like on right side of car), took it to the chevy dealer and they said it was the torc converter, what should I be concerned about.

  7. My check engine light is on and my reverse went out but all the other gears work sometimes the check engine light goes off and comes back on

  8. 03 Honda Civic coupe 1.7 ltr w/ 200k. I recently had the A/T shudder fixed by draining old fluid out 3 seperate times with Genuine Honda ATF. Then, about 6 months later I get the P0740 code with no symptoms at all. She runs great.I changed the TTC solenoid with the OEM part from the dealer. CEL still on, it stays off for like 50 miles when I clear the code, but always returns. I’m thinking of swapping out the Linear Solenoid next but its real expensive from the dealer. Any advice?

  9. I’m driving a 2007 Entourage with 310,000 miles. I have changed the trans mission fluid and filter every 50,000 miles. I’ve been getting a P0740 code without any manifestations for the last 50,000 miles. The transmission fluid is still clean and pinkish How do I test the solenoids and where are they located
    Thank you

  10. Due to very high demand and a high amount of comments, you might have trouble getting your comment answered by me. If you want to get fast answers from a certified automotive technician you should ask your questions here: Ask A Mechanic

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