What Is P0405 Code on 6.0 Powerstroke? and How to Fix it?

Your truck shows some codes if there is anything wrong with your vehicle. There are two computer systems for cars, and those are known as OBD-1 and OBD-2. 

The vehicle that came before 1996 uses the OBD-1 generic code, and the vehicle that came after 1996 uses the OBD-2 generic code. The P0405 code is an OBD-2 generic code that refers to a specific problem with your truck. So, what is the P0405 code on the 6.0 Powerstroke?

You will find the answer in this article. We are here to shed light on this topic and share the details with you. So, if you want to know the potential causes and consequences of this code, then follow the article.

What Does P0405 Code Mean?

Code P0405 is an OBD-2 generic code. As it is a generic code, the meaning is the same for all vehicles, including the 6.0 Powerstroke. This code indicates there could be a problem with the EGR valve or fluctuating voltage level, or any issue in the EGR system. 

So, what does EGR refer to? EGR stands for Exhaust Gas Recirculation. It’s a pollution-reduction method for diesel and petrol engines. The exhaust gas goes to the cylinder directly. Then the mixing of exhaust gas and the intake air is controlled by the EGR valve. As a result, less oxygen enters the cylinder.

When there is less oxygen in the cylinder, the combustion temperature decreases. If we say it in simpler words, the goal of the EGR system is to reduce the nitrogen oxides of nitrogen created while the engine is running. Nitrogen oxide emissions can be cut by 70%. In a petrol engine, this can reduce carbon dioxide production as well.

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What Are The Symptoms of P0405 Code?

The 6.0 Powerstroke tends to show symptoms when getting the P0405 code. Your vehicle may show any symptoms while having a problem inside. Now let’s see the symptoms.

  • The check engine light will be activated.
  • The nitrogen dioxide quantity will increase.
  • Failed emission test
  • Your vehicle will show poor performance.
  • Fuel consumption will increase.
  • You can even experience a stalling engine.
  • In some cases, the knocking noise comes from the engine as well.

Potential Causes for Showing The P0405 Code

Now let’s see the causes behind the P0405 error.

  • The main cause is the defective EGR valve.
  • A faulty position sensor of the EGR valve
  • Plugged EGR passages
  • Faulty EGR solenoid
  • Restricted intake EGR PASSAGES
  • Carbon build-up causes the valve to be opened or closed
  • Damaged vacuum line
  • Bad EGR gasket
  • Poor connections

How to Solve P0405 Code Issue?

To fix the error P0405 code, you can follow the procedures below. So, without further ado let’s get started.

EGR Valve Cleaning

At first, open the hood and locate the EGR system. And follow the steps below. 

  • To find the EGR valve, locate the exhaust manifold and then find the pipe that comes out of it. 
  • Now, follow the hose. It will take you to the back of the intake. You will find the EGR valve there. 
  • The valve may be gummed up with carbon deposits over time. 
  • Remove the two nuts, and your EGR valve will pop off.
  • Secure the vacuum diaphragm and vacuum port with a protective layer so that the cleaner that you will be using to clean the carbon deposits doesn’t get into those parts.
  • Apply a generous amount of cleaner to the valve and clean properly.
  • After cleaning the EGR valve, set it up in the EGR system as it was before and check if it still shows the code.
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EGR Valve Replacement

If the EGR valve cleaning doesn’t work and the P0405 code still appears, then your valve might have gone bad and need a replacement. 

As we have explained how to locate and remove an EGR valve in the previous section, follow those steps and remove the valve. 

Now, take a new EGR valve that matches your previous EGR system and place it in the right position by fastening the nuts that keep it attached to its place. After replacing the valve, the error should not return. 

PCM Replacement

If these two methods don’t work on your vehicle, you might need to change the PCM. A PCM is a powertrain control module. Check the voltage of your PCM and see if it shows 5 volts. 

It is the required electricity that the EGR valve requires from the PCM. If your PCM is faulty, it won’t show any voltage. 

Now, go to the mechanic and get your PCM replaced by an expert, as this part is very sensitive and hard to restore for an amateur.

Some Do’s and Don’ts When you solve this Issue

People usually make some common assumptions that their EGR system is faulty and needs a replacement to solve the issue. When the reason behind this error code can be simple, and you don’t even need to spend too much money and time during the process.

That is why you begin with the simplest solution and progress to the most critical one. Check every connection, wire, and part carefully at first. A proper inspection is required to find out the core of the problem.

If you are unsure and can identify the faulty part, then consult an expert and take professional help.

What is the Cost of Solving the P0405 Code Issue?

If you can diagnose the problem and have the skills to repair or replace the parts of the truck, then you only need to spend money on the product.

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But while taking professional help, it will add labor costs as well. The cost of labor can be between 60 and 150 dollars. Now let’s see the cost of the new parts. 

  • The price of an EGR valve is around 200 dollars.
  • The price of PCM is around 500 dollars.


Where Is The Exhaust Valve Located?

Answer: The exhaust valve is an important part of the EGR system, which is located between the intake and exhaust manifold.

What Are EGR Valves Made of?

Answer: An EGR valve is made with a valve, a diaphragm, and a vacuum port. And the material is usually alloy steel.

Does EGR Affect Performance?

Answer: Yes, it does. A faulty EGR can decrease the overall performance of your vehicle while spending more fuel than usual. A good EGR can increase the performance of your vehicle and keep the engine cool.

Can You Drive Without an EGR Valve?

Answer: It is okay if you want to remove EGR and run without having one. It is also legal and doesn’t cause any harm to the engine.

Final Words

Generic code is a universal language. Although we have shared the details about the 6.0 Powerstroke, you can apply these methods to any of your vehicles as well. Always follow the symptoms first, look for the causes, and then reach the diagnosis. 

To solve any automotive issues, you don’t necessarily need to be an expert or master of your vehicle. Just follow the basic instructions and save both your time and money by decoding the problem independently. 

Now, if anyone asks you, “what is the P0405 code on the 6.0 Powerstroke?” you can confidently provide the right information to the questioner.

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Brian Polk

Brian is an automotive expert who has 12 years of experience in the industry. He has worked on a variety of cars, from high-end luxury vehicles to budget-friendly options, and has a wealth of knowledge on the subject. He is passionate about automobile and enjoys sharing his knowledge with others, whether they are looking to purchase a new motorized vehicle or simply learn more about the inner workings of these machines. In his free time, Brian enjoys working in his automobile workshop and spending time at the track.

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