P0777 code — how to fix error fast

If you never faced an OBD2 code before, retrieving the P0777 code on a diagnostic scanner can be a cause for concern. While some codes are “less dangerous” than others, you simply have to fix the underlying issue that caused each of these to ensure your car runs properly.

The same goes for this one since the P0777 code meaning is closely related to one of the key systems of your car – the transmission. So, to help you out in the best possible way, our team created this guide with all the steps on finding the reason behind the code, diagnosing it, and finally clearing it with a low chance of it ever coming back on.

Why you can trust REREV’s OBD2 code advice: Our automotive expert researchers with experienced mechanics undertakes a thorough research methodology to deliver precise insights on OBD codes. Find out more about OBD2 codes research process..

What does the P0777 code mean?

The P0777 code is a generic powertrain code that indicates a problem with the transmission control system. This code is specifically related to the pressure control solenoid, which is responsible for regulating the hydraulic pressure in the transmission.

It is important to understand the code because it can cause serious damage to your car if left untreated. To put it simply – the torque converter uses the proper amount of hydraulic pressure to help shift through the gears at a defined ratio. If the pressure is lower or higher than it should be, you may encounter transmission damage or even complete breakdown if not treated on time.

What causes the P0777 code?

The P0777 code can be caused by a wide range of issues, including a faulty pressure control solenoid, a damaged wiring harness, a faulty transmission control module, or a low transmission fluid level. Let’s take a closer look at each of these potential causes.

Faulty pressure control solenoid

The pressure control solenoid is responsible for regulating the hydraulic pressure in the transmission. If this solenoid is faulty, it can cause the P0777 code to appear. Symptoms of a faulty pressure control solenoid include harsh shifting, delayed shifting, and transmission slipping.

Damaged wiring harness

The wiring harness is responsible for transmitting electrical signals to the transmission control module. If the wiring harness is damaged, it can cause the P0777 code to appear. Symptoms of a damaged wiring harness include intermittent shifting problems and erratic shifting.

The faulty transmission control module

The transmission control module is responsible for controlling the shifting of gears in the transmission. If the transmission control module is faulty, it can cause the P0777 code to appear. Symptoms of a faulty transmission control module include shifting problems and delayed shifting.

Low transmission fluid level

Finally, a low transmission fluid level can cause the P0777 code to appear. This is because the pressure control solenoid requires a certain level of hydraulic pressure to function properly. Symptoms of a low transmission fluid level include slipping, delayed shifting, and rough shifting.

Which car models does the P0777 code affect the most?

In essence, any car with an automatic transmission could be exposed to the code P0777 sooner or later, so it mostly depends on mechanical factors. However, our team received numerous reports on certain car models that are said to be more prone to this code, so here’s a list we created after checking up on this:

• Acura MDX: The 2001-2006 Acura MDX is one of the most affected car models by code P0777. The issue seems to be more common in models with higher mileage.
• Honda Ridgeline: The 2006-2014 Honda Ridgeline is another model that can be affected by code P0777. This issue can cause various transmission-related symptoms, such as delayed engagement, erratic shifting, or transmission overheating.
• Honda Pilot: The 2003-2008 Honda Pilot is also known to have issues with the pressure control solenoid B, which can trigger code P0777. This problem can lead to transmission slipping, harsh shifting, or even transmission failure if left unaddressed.

How to diagnose the P0777 code

Listing all the previously-mentioned reasons behind the code becomes useful when it comes to diagnosing the problem. You can test each of the affected components to see if that’s the root cause of the trouble and we recommend you stick with the following diagnostic methods:

Use an OBD2 scanner

The most common way to diagnose code P0777 is by using an OBD-II scanner. This tool can read and interpret the diagnostic trouble codes stored in the vehicle’s computer system and provide information on the specific issue that triggered the code.

You may also be able to read other codes that are active and related to the P0777 code to provide some more information about the background of the problem that caused the code.

Perform a visual inspection

Sometimes, the issue causing code P0777 could be a loose or damaged connector or wiring related to the pressure control solenoid B. In these cases, a visual inspection of the transmission system may reveal the source of the problem.

You can look for any visible signs of damage or wear on the transmission components and check for loose connections or broken wires that could be causing an electrical fault.

Checking the transmission fluid level and condition

The condition of the transmission fluid can also provide valuable insights into the health of the transmission system. If the fluid is dirty or contaminated, it could indicate that there is a problem with a component in the transmission, including the pressure control solenoid B.

How to fix the P0777 code

The fix for the P0777 code will depend on the underlying cause. If you’ve already diagnosed the core of the issue and are ready to take the next step, here are some potential fixes for each cause of the code:

Replace a faulty pressure control solenoid

The cost for this repair can range from $250 to $500, and it can hardly ever be repaired so you might have to pay the price of a new component. However, it all pays off since the fluid pressure should be properly determined again and you at least won’t have any other problems with the transmission.

Damaged wiring harness

If the issue was caused by damaged wiring harnesses or electrical connections, you can repair or replace the affected components. The cost for this repair can range from $150 to $300.

Deal with a faulty transmission control module

Replacing the transmission control module can be among the most expensive ways of fixing this code, so you have to be absolutely certain that the TCM is the reason behind it. If that’s the case, you should be prepared to spend anywhere between $500 and $1500 on replacement depending on the car model.

Low transmission fluid level

This is an easy fix and you can even do it yourself. If the source of the problems seems to be a low transmission fluid level, you can simply top it up and get the hydraulic pressure restored for minimum repair costs.

How to prevent the P0777 code

There are several preventative measures that you can take to prevent the P0777 code from appearing. Here are some tips:

• Check the transmission fluid level regularly and top it off as needed
• Replace the transmission fluid and filter according to your vehicle’s recommended maintenance schedule
• Inspect the wiring harness for damage or corrosion regularly
• Replace the pressure control solenoid every 100,000 miles or as recommended by your vehicle’s manufacturer

It’s often enough to stick with regular maintenance and check the transmission fluid level from time to time to ensure that there are no conditions under which the code would emerge.

Our take

We know that the P0777 code can be a frustrating experience for you, but with the right knowledge and tools, it can be diagnosed and fixed quickly and easily. By following the preventative measures outlined in this article, you can help prevent the P0777 code from appearing in the future, so our team hopes we did well in helping you out.