Harry Gibson on March 1, 2023 No Comments
Are you facing some problems with erratic shifting and you have diagnosed the P0740 code? Well, if that is the case, then you are at the right place because there will be a lot to cover on this topic where we will learn how to tackle this problem.
Having a problem like this can be a really frustrating thing to deal with. Mainly because it greatly affects your transmission and its ability to shift gears. You will face a ton of problems down the alley trying to figure it out how to tackle this problem with your car but sometimes the solution is really simple.
But more on that later on in this article, what is important for you now is to understand the basics of car diagnostics and how this work is performed on a car. Knowing this stuff will save you a ton of money and also will make you a better mechanic and a better person. Who knows, someday maybe you will be someone who will make money from fixing cars and this is why we are here to encourage you and teach you how this is done.
First, we will cover the basics of car diagnostics, then we will discuss the basics of torque converter automatics and how they work. Then we will elaborate more on the P0740 and learn why this code appears in the first place and we also going to discuss the TCC Solenoid. Later on, we will cover the causes, symptoms, and how to diagnose the problem. So, if you want to learn more, please follow along.
Introduction To Car Diagnostics
Before we dive into the problem with the P0740 code, let’s learn some of the basic stuff when it comes to car diagnostics. I bet that there are a ton of people who are reading this who are not aware of how this procedure is done the right way and need some introduction in diagnosing this stuff on their vehicle. So, this chapter is dedicated to them.
When it comes to car diagnostics it is important for you to understand that nowadays everything is computerized. This means that you can only get access to the car computer with a special tool that is known as an OBD2 scanner.
Every car has an OBD2 port that is located under the front dash on the driver’s side or underneath the central console. Depending on the vehicle that we are talking about.
Then with this tool, you can get access to the trouble codes as well as read live data from different sensors if you opt to get a more advanced scanner. The live data is one of the most useful pieces of information that you can have because you will be able to tell based on this data if the component is performing as it should or not.
Then you can move on and bench test it just in case with a multimeter tool and see if this component is performing as it should or not. Which in our case is the TCC solenoid. But more on that later on in the article where we will cover the TCC solenoid in detail. Now let’s cover more about the P0740 code and learn if this code is really a big problem.
P0740 Torque Converter Clutch Circuit Open
Now let’s elaborate more on the code and learn the P0740 meaning, what this code means in the first place?
Well, this is a generic trouble code that appears in vehicles that are produced after 1996 and includes the OBD2 port. It’s a generic code which means that it is associated with all carmakers, it doesn’t matter if you drive a Honda, Toyota, Ford, Chevy, or another car. All of them will report this type of code if you have a torque converter automatic transmission. But what is the definition of this code?
Well, the definition of this code is “P0740 Torque Converter Clutch Circuit Open” or “P0740 Torque Converter Clutch Circuit Malfunction”. This basically means that you have a malfunction in your TCC solenoid.
The electrical circuit inside of the solenoid is probably bad or something else is making this solenoid not perform as it should and you get this code.
This is why you should not jump to conclusions and you need to study all the different causes and symptoms of this problem with the P0740 and which we are going to discuss later on in this article.
What is important for now is to learn more about the operation of the TCC solenoid and learn its basic functions. This way, you will be able to tell if you are having a bad TCC solenoid or possibly another problem that makes this solenoid malfunction and you face issues like these. So, if you want to learn more on this topic please follow along.
TCC Solenoid
As we covered the P0740 code, now it is time to discuss more about the TCC solenoid. This component is important to us because this component is the one in charge of controlling the torque converter on your automatic transmission. And when it fails, you get a ton of issues including the P0740 code. So, what is the TCC solenoid?
Well, the TCC solenoid is referring to the torque converter clutch solenoid. This component is in charge of the torque converter and whenever it fails and you get a P0740 code you are having a bad torque converter clutch solenoid circuit.
The solenoid works like any other solenoid device. It has a coil that has continuity and whenever it fails it can get stuck in an open or closed position. In our case, the electrical circuit is open which means that the solenoid is active all the time. Which is not a good thing.
But sometimes these problems can be caused by different things inside of the transmission and the solenoid is only the one component that gets faulty. But more on the causes later on.
What is important for you to know when it comes to the operation of this solenoid is that this solenoid regulates the torque converter. Inside the torque converter, there are mechanical clutches. These clutches are creating a mechanical connection between the transmission and the engine. Thus, reducing the RPM of the engine, lowering the temperature of the transmission fluid as well as increasing the fuel economy.
So, you can imagine how beneficial is the TCC solenoid. This solenoid makes your engine work more efficiently. And when it fails, you will face some of the P0740 symptoms.
Causes For The P0740 Code
Now let’s elaborate more on the causes of the P0740 code. As you probably know, there is the possibility that the solenoid could be dead.
But there are also a few other probabilities on the table as well. This is why you need to learn them before you rush too soon and replace a good working TCC solenoid. Now let’s elaborate more on the probable causes and learn what could be the culprit.
1. Defective TCC Solenoid
The first and most common cause of the P0740 is a bad TCC solenoid. Sometimes these components reach the end of their lifetime and they simply stop working.
The solenoid will not activate and distribute transmission fluid anymore. Like in our case when the solenoid is stuck in an open position.
This means that there is a constant flow of transmission fluid and the car’s transmission simply starts malfunctioning.
What is important to note is whenever this solenoid is stuck in an open position it could be detrimental to your transmission, you should avoid driving this way and you should consider visiting a mechanic as soon as possible if you want to avoid damage to be done to the transmission internal components. Now let’s move on to the next probable cause for the P0740 code.
2. Faulty TCC Solenoid Circuit
The second most common cause of the failure of this solenoid is the failure of the electrical circuit of this solenoid.
As you probably know this solenoid is mounted inside of the transmission and is basically submerged in transmission oil. There are wires that go to this solenoid and sometimes if, for example, the transmission overheated, it could damage these electrical components inside itself.
There could be a fault inside the circuit of this component and it could fail internally. This is the most obvious reason why you are getting the P0740 code. And similar to the first cause, the only solution for this problem will be to replace the TCC solenoid with a new one. This will fix the problem in most cases. But there are still some other options that could cause this issue and we are going to cover them next.
3. Low Level Or Dirty Transmission Fluid
Another common cause that could make the TCC solenoid malfunction and trigger a P0740 code or a similar code is the low level of transmission fluid or dirty transmission fluid.
Your transmission solenoids do not like when the transmission fluid is low or if it’s too dirty. They will start to malfunction and possibly fail. In this case, the transmission will overheat and when a transmission overheats, you need to do a rebuild or replace it.
And the prime goal of this TCC solenoid is to protect the transmission from overheating and prolong its lifespan. So, you always need to be aware of the transmission fluid levels as well as the condition of the fluid. Make sure that the fluid is clean and that you are driving with clean fluid on your car in order to avoid the P0740 code.
4. Internal Problem With The Transmission
The next probable cause for the P0740 code is an internal problem with the transmission. Sometimes components inside of the transmission such as the valve body or other integral components fail and cause trouble like in our case.
So, whenever this problem with the P0740 code happens it is worth checking the transmission components as well. Namely, the torque converter. Because sometimes it is not up to the solenoid, sometimes the damage is far greater and the solenoid is one that malfunctions because of this situation and causes you a ton of trouble. Now let’s move on to the last probable cause for the P0740.
5. Software Issues
And the last in our list of probable causes for the P0740 code are the problems with the software. Modern transmissions are computerized. This means that their work really depends on pre-programmed software.
Sometimes especially on newer models, there are software updates that fine-tune the transmission and deliver the best result from it. So, if you got an early model, you might have a problem with old software on your car. Just take your car to the shop and let them update the software and call it a day. Now as we finished with the causes, let’s move to the symptoms of the P0740.
Symptoms Of The P0740
We have covered the probable causes for the P0740 code, now it is time to learn more about the symptoms that you could face when you have a bad TCC solenoid on your car.
Knowing these symptoms will greatly help you when it comes to diagnosing this component and hopefully sorting the problem out. So, without further ado, let’s cover the symptoms before we learn how to diagnose the issue on your car.
1. Check Engine Light
The first and most important symptom for you is the check engine light. And if you have diagnosed this light and you found out that you have the P0740 code, you are probably aware of it.
What is important to add here is that whenever the check engine light occurs and you have this code, there might be some other codes as well that are closely associated with this problem.
More precisely the codes, are P0741, P0742, P0743, P0744, P2769, and P2770. All of these codes are closely associated with this TCC solenoid and the torque converter clutch. Now let’s move on to the next symptom.
2. Erratic, Delayed, Or Hard Shifting
The second symptom when it comes to the P0740 code and the TCC solenoid that we would like to cover are issues with shifting.
Whenever you have a bad TCC solenoid, you might experience erratic shifting, delayed shifting, or even hard shifting.
Gear shifts always have to be perfectly smooth and timed out. If the transmission is running the engine on high RPM and delivering the shifts, then this is not good. You are in a bad situation because this transmission is really unpredictable and could ruin your driving.
So, whenever you notice something like this. Try to diagnose the problem and the problem in most cases is connected with the TCC solenoid and the P0740 code.
3. Transmission Shudder
The third most common symptom associated with the TCC solenoid and the P0740 code is the problem with the transmission shudder.
The transmission shudder is a situation when you experience vibrations when the transmission is shifting. So, if you notice some vibration coming from the center console, it means that you have probably bad transmission mounts or the transmission shudders. So, beware of this symptom as well.
4. Decreased Fuel Economy
The fourth most common symptom of a P0740 code and problems with the TCC solenoid is the decreased fuel economy. But why is this the case?
Well, this is often the case because the transmission is shifting erratically. It doesn’t work as efficiently as it should work. It pushes the RPM range sometimes to the maximum in order to shift.
And as we all know, whenever you push a car over the limit, you will face problems like poor fuel economy. This can really hit your wallet. Especially now when gas is so expensive. So, whenever you notice erratic shifting and decreased fuel economy, you just know where to look to solve your problem. Diagnose the car and see if you have a P0740 or similar code and check the TCC solenoid. More on that we will cover in a bit.
5. Overheated Transmission
The number five and last symptom in our list of bad TCC solenoid symptoms and P0740 symptoms is the overheated transmission.
As we noted, this solenoid is keeping the transmission temperature in check. So, whenever it starts not to work well, you will experience problems such as overheating and other shifting issues.
And when once this transmission starts to run hot. It could fail at any moment. This is why you need to jump into diagnosing the matter and sort out this issue. But how this procedure is done? Let’s learn more about that next.
How To Diagnose & Fix The P0740 Code?
Now, let’s say that you have diagnosed the P0740 code on the car. What can you do in this situation to sort out this problem with your car?
The first thing you will have to do is to locate this TCC solenoid. And frankly, for this purpose, you will need some skill because this solenoid is inside of the transmission. So, the oil pan and transmission fluid have to be removed in order for you to gain an access to this TCC solenoid. And only then you can bench test it and see if it works.
If you are lacking the equipment and skills needed, you might better leave this work to your local transmission shop and let them deal with it. Or if you are very persistent and you removed this solenoid, the next thing will require to bench test it.
Since this component is a solenoid, you should measure its resistance of it. This means that you should tweak the multimeter to measure ohms. Place the probes into the solenoid and see the readings that you get. For a good TCC solenoid, you should get between 15 to 25 ohms. If the levels are much higher or lower, you probably have a bad TCC solenoid.
Or if the solenoid is in good condition, you might want to look at other components such as the wiring as well as the TCM or the torque converter itself. This component can also fail and cause trouble like these with the P0740 code.
Cost To Fix P0740 Code
So, what is the cost to fix the P0740 code on your car? Well, on average the cost is between $300 to $500. The solenoid itself is about $100 in the worst cases. But the drawback is that the labor is expensive.
This is the case because the TCC solenoid has to be removed and inspected. And as you can notice this solenoid is inside of the transmission, so it has to be pulled out and this requires work.
Also, if the clutches in your torque converter are bad, you can expect to replace the torque converter. A single torque converter can cost about $500 or more in some cases.
P0740 Code Facts: Troubleshooting Torque Converter Clutch Circuit Malfunction
- The P0740 code definition is a torque converter clutch circuit malfunction.
- The powertrain control module (PCM) triggers a Check Engine Light if it detects something unusual within the torque converter clutch circuit.
- Some potential causes of the P0740 code may include a faulty torque converter clutch solenoid, damaged torque converter or clutch, incorrect transmission fluid level, skipping over transmission maintenance, a restriction within the transmission, internal transmission damage, or a faulty powertrain control module or transmission module.
- Symptoms of a P0740 code that the driver may experience include the transmission not shifting in or out of a particular gear, the transmission may shift harshly, the torque converter clutch may not engage or disengage causing the vehicle not to move, the engine may stall, or the transmission could overheat.
- A mechanic may diagnose the P0740 code by checking the transmission fluid level and condition and using service information to look up a diagnostic procedure for this code given by the manufacturer and then following the instructions given.
- An easy mistake that could be made when diagnosing the P0740 code is assuming that the torque converter is damaged just because this part is listed in the trouble code.
- The P0740 code can be very serious as it can cause drivability issues, leaving a driver stranded on the side of the road.
- Repairs that can fix the P0740 code may include replacing the torque converter clutch solenoid, replacing the torque converter or clutch, adding or replacing transmission fluid and filter, replacing the powertrain control module, overhauling the current transmission, or replacing the transmission with a brand new one.
- It is a good idea to replace the transmission fluid in your vehicle along with the filter (if applicable) at the recommended intervals to prevent trouble codes such as the P0740 code.
- Properly diagnosing and repairing the P0740 code is important to ensure a properly operating transmission to transfer the engine power to the wheels.
Conclusion
In this article, we have covered quite a bit when it comes to the P0740 code and how to diagnose it in the right way.
First, we learned the basics of car diagnostics and elaborated more on the code. Then we learned the causes and the symptoms of this code.
After we learned how to diagnose and fix the problem with this trouble code. And how much you can expect to pay to fix this issue.
F.A.Q
Now let’s answer some frequently asked questions.
Where Is The Torque Converter Clutch Solenoid Located
The torque converter clutch solenoid is located on the valve body of the transmission. Which means that it is mounted behind the oil pan of the transmission. For the exact mounting position, you can consult with sources online that will pinpoint the exact location for your transmission type.
What Does P0740 Code Mean
This code means that the torque converter clutch solenoid has an open circuit and is malfunctioning. The TCC solenoid needs to be removed from the car and bench-tested in order to determine if this component is causing the problem.
How To Fix P0740 Code
Fixing this problem will require the removal of the TCC solenoid from the car and testing it. If the solenoid is in good condition, it might be some other cause for this code and this needs to be further diagnosed so the right cause to be determined.
How Long Can I Drive With Code P0740
You can drive as long as you want. But it is not recommended to do so because you are risking the health of your transmission. This is the case because whenever this solenoid is not working as it should. The transmission will start to overheat and suffer from internal damage.
