P1790 code — how to fix error fast

Driving a car with an automatic transmission can be pretty rewarding, but it also comes with the risks of experiencing specific OBD2 codes like P1790. If this happens with your vehicle, it’s crucial to stay calm and get to the bottom of it before driving your car again to prevent severe transmission damage.

While this is not as easy as it sounds, our team of automotive experts will make things simpler through this guide on P1790 code meaning and implications. We’ll go on an in-depth tour of the code’s main triggers and what you can do as a remedy.

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What does the P1790 code mean?

The P1790 code signifies a problem in the transmission control module’s torque converter clutch system. When the transmission control module detects a fault, it triggers the code, which illuminates the check engine light.

If you don’t act on time, it could affect your vehicle’s transmission and driving safety, so it’s as urgent as it gets with OBD2 codes. Some of the main symptoms of this one include the “check engine” light coming on, rough gear shifts, and problems with gear shifting.

What causes the P1790 code?

There are several possible threats that could lead to the illumination of the code on a scanner device. Our team believes that it’s best to know about all of these in detail to apply an appropriate solution, so here’s a complete list:

Faulty torque converter clutch solenoid

The torque converter clutch solenoid regulates the flow of transmission fluid to the torque converter. If the solenoid fails, it may cause the P1790 code to appear.

Damaged wiring

Damage to the wiring of the torque converter clutch solenoid may cause the code as well. The damaged wires may cause a short circuit or an open circuit, leading to a malfunction in the system.

Defective torque converter

If the converter is either worn out or damaged, system malfunctions could occur and that triggers the P1790 code in this case.

Transmission control module failure

The transmission control module is responsible for regulating the torque converter clutch system. If the module fails, it could possibly be the culprit behind the code’s activation.

Which car models does the P1790 code affect the most?

Considering that there are so many vehicles with an automatic gearbox these days, it gets difficult to figure out if certain models are more susceptible to this code than others. That’s why we did our best to go through the files and driver complaints which helped us come up with this list:

• Nissan Altima: This model has been known to have issues with its TCM and can trigger the P1790 code.
• Ford Focus: This model has had several transmission-related issues, including problems with the TCM that can cause the code to appear.
• Jeep Grand Cherokee: Some drivers of this model have reported issues with the TCM, which can be responsible for triggering the P1790 code.

How to diagnose the P1790 code

Diagnosing the P1790 code requires specialized diagnostic tools and equipment. Here are some of the steps to follow when diagnosing the code:

Use an OBD2 scanner

Connect a diagnostic scanner to the vehicle’s OBD-II port and retrieve the code. The scanner will provide a detailed description of the code and its potential causes.

Look for other codes

While you are at it and using a scanner, you can look for other codes that could be triggered by the malfunction in the torque converter clutch system. Addressing all the codes will help ensure that the problem is fixed.

Check the transmission fluid level

You can also check the transmission fluid levels to ensure that they are at the recommended levels. Low fluid levels may cause the torque converter clutch system to malfunction.

Inspect the wiring

Inspecting the wiring of the torque converter clutch solenoid for any damage or corrosion could save you the trouble of paying for costly transmission repairs if the wiring issues were the source of the problem.

Test the torque converter clutch solenoid

Finally, you can test the torque converter clutch solenoid using a multimeter. Ensure that the solenoid is receiving the recommended voltage, and the multimeter will tell you if the clutch solenoid is still doing its job properly or not.

How to fix the P1790 code

Fixing the P1790 code requires addressing the root cause of the problem. We’ll give you some ideas on what you can do to fix the issue depending on what’s causing it in your car:

Replace the torque converter clutch solenoid

Replacing the faulty torque converter clutch solenoid will help address the P1790 code if the bad solenoid was the culprit of the issue all along. Even if it’s not, it’s recommended to inspect the solenoid every now and then to ensure proper transmission system maintenance.

Repair or replace damaged wiring

If the wiring of the torque converter clutch solenoid is damaged, you can replace the connections or repair them to get the solenoid back on track and working again.

Replace the torque converter

Changing the worn-out torque converter is yet another great way of removing the code assuming that the torque converter has been causing the trouble. Rough shifting or difficulties shifting to a certain gear all indicate and issue with the converter and poor pressure buildup within the system.

Replace the TCM

Replacing a TCM should come as a last resort option since it’s usually pretty expensive. Still, you should make sure that the TCM is operating properly to control the gearbox performance, and if it’s not, it’s likely what’s been causing the code in your car all along.

How to prevent the P1790 code

With the proper maintenance of the vehicle’s transmission system, it could be possible to prevent the code from triggering again. Here are some of the preventative measures to take:

• Regularly check the transmission fluid levels and top up as necessary
• Regularly inspect the wiring of the torque converter clutch solenoid and repair or replace any damaged wires
• Have the transmission system serviced regularly by a qualified mechanic

This should help keep your car’s transmission running properly without having to change anything or deal with the code all over again.

Our take

As it turns out, the P1790 code is a crucial diagnostic trouble code that requires immediate attention. Identifying and fixing the root cause of the problem will help prevent severe damage to the transmission system.

That being said, we hope that this guide will set you on the right track toward solving the problem without breaking the bank on expensive transmission repairs.