P0740 It is one of the most common transmission fault codes. It means that the CaravanThe caravan computer has detected that there is a problem with the torque converter clutch (TCC) solenoid circuit.
P0740: Torque Converter Clutch Circuit Failure
The TCC “locks” the transmission, allowing a true mechanical connection between the transmission and the engine. In effect, this allows an automatic transmission to operate like a manual transmission at certain speeds and engine loads and eliminates all transmission slip.
P0740 Symptoms: Dodge Caravan
The symptoms of P0740 are very varied. If the converter remains unlocked, it can be a nuisance. If it crashes when it shouldn’t, that’s where it can get complicated.
The most common symptoms are:
- Low Mileage – If the converter does not lock up at speed, the engine RPM remains higher. This reduces fuel consumption.
- Stutters and stalls – This would be a sign that the transmission is blocking when it should not be. It feels exactly the same as when you have to downshift in a manual transmission.
- Higher RPM on the highway – If the converter does not lock up, the RPM on the highway may increase. This increases fuel mileage and makes the transmission run hotter.
- The service engine soon light
Here is a great video on diagnosing this code:
P0740 Causes Dodge Caravan
There are many different things that can cause the P0740 code. Most of them are going to need the touch of an expert to diagnose them.
This list is presented considering first the probability of causing the problem and the possibility of repair.
Yes, there is not sufficient transmission fluid, so the transmission will not be able to operate normally. There are many symptoms that the transmission fluid is low. The most noticeable will be transmission slippage.
If the transmission fluid is dirty or burned may cause the transmission to behave non-normally and return the P0740 code. Here’s a pretty good guide on transmission fluid color.
If the fluid is low or bad, replacing it should be considered an urgent priority. The good news is that transmission fluid and filters are cheap.
The wiring harness that runs to and from the transmission is one of the most vulnerable pieces of wiring in a vehicle. Inspecting the wiring harness for obvious signs of deterioration, checking the connection in the transmission itself, and finally performing a continuity test can go a long way in diagnosing your Caravan.
It is very likely that the torque converter clutch (TCC) solenoid has gone bad. But jumping right to this conclusion without inspecting the transmission fluid and wiring can cause a lot of undue headaches.
The torque converter itself or the torque converter clutch can go bad and return the P0740 code.
The problem in the case
If the TCC appears to be working correctly, the problem may be with the transmission case itself. It could be a valve body problem, a problem with the pressure going through the transmission, or a clogged filter.
The articles on this site are always written with the DIY enthusiast in mind. Most of the time, you’re not looking for these codes for a casual read. You are looking for them to fix your vehicle. We would never want to discourage that. That said, P0740 is a more difficult code to diagnose and is often beyond the reach of the shadow mechanic.
If there is anything you want to add, don’t hesitate to leave a comment.