P0401 Ford Vehicles? (Correct answer)

The OBDII fault code P0401 means that the engine computer has detected that the Exhaust Gas Recirculation (EGR) system flow is insufficient. The EGR system redirects a small amount of exhaust gases back into the intake.


  • Meaning: What is the P0401 Code on Ford The P0401 code stands for the Exhaust Gas Recirculation Flow Insufficient Detected. EGR or Exhaust Gas Recirculation is a system for decreasing the amount of NOx in the exhaust.

How do I fix code P0401 on my Ford?

What repairs can fix the P0401 code?

  1. Replacing the leaking or clogged EGR valve.
  2. Replacing a broken vacuum line to the EGR valve or control solenoid.
  3. Replacing an EGR temperature sensor or clean the carbon off of it to repair it if it does not register enough of a temperature change.

What causes EGR insufficient flow code?

Faulty EGR valve. A failed sensor (e.g., differential pressure sensor, manifold absolute pressure sensor, etc.) Inadequate vacuum supply to the EGR valve. Circuit problems, such as damaged wiring and loose connections.

What could cause a P0401 code?

Code P0401 Meaning EGR valves can malfunction by becoming stuck open or closed due to carbon buildup. This is likely due to faulty or clogged EGR valve or carbon buildup in the intake manifold or on the EGR temperature sensor.

Can you drive with a P0401 code?

Hi There, Code P0401 relates to the EGR valve flow. When this code is triggered, the computer has detected that the flow is insufficient. Driving the car until next week will not cause any harm, although the vehicle may not run well.

How do you reset the check engine light after replacing the EGR valve?

It’s best to reset the check engine light with a scan tool but disconnecting the battery for a few minutes will erase all memory and turn off the Check Engine light, make sure you have radio security code prior to removing battery connection.

How do you fix EGR insufficient flow?

How to Fix

  1. Use vacuum pump to open the EGR valve while monitoring the DPFE voltage and RPM engine.
  2. Clean the EGR valve and tubing to remove the deposits.
  3. Check the voltage at DPFE and compare to specified values, You can also refer to your repair manual for your specific model.

Can an exhaust leak cause EGR code?

The only way an exhaust leak can cause a rough idle is if the leak was in a place where it could enter the air intake system. On some engines there is a pipe that takes exhaust gases from the exhaust system to the EGR valve.

What is code P0404?

When P0404 is triggered, it means that the PCM has been told that the valve is performing in a way that is outside of its specified parameters. More specifically, the PCM has been told that the valve is closed when it should be open, or vice-versa.

What is code P0402?

Diagnostic Trouble Code (DTC) P0402 stands for Exhaust Gas Recirculation “A” Flow Excessive Detected. It indicates that the powertrain control module (PCM) has detected excessive EGR. It is one of the generic diagnostic trouble codes in a number of makes and models that are related to the vehicle’s EGR.

What is the code P0403?

Diagnostic trouble code (DTC) P0403 stands for “ Exhaust Gas Recirculation “A” Control Circuit.” The exhaust gas recirculation (EGR) system helps minimize nitrogen oxide gases coming from your vehicle’s exhaust. The ECM/PCM detects an open circuit condition of an EGR motor control circuit for greater than 3 seconds.

What is P0400 code mean?

Diagnostic trouble code (DTC) P0400 code stands for “ Exhaust Gas Recirculation (EGR) Flow Malfunction.” It is triggered when the flow of exhaust gas recirculation is lower than what the powertrain control module (PCM) expects.

Dealing With Ford P0401 Code Issues

You’ll be OK driving without replacing your EGR valve, but the environment and your bank account will not be pleased. EGR valves reduce the quantity of emissions that escape from your automobile, allowing you to get more mileage out of your tank. In the long run, scheduling an appointment with Wrench at your home or place of business for an EGR valve repair will save you money.

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Code P0401-Exhaust EGR Flow Insufficient

The most recent update was on July 25, 2021. The OBDII error code P0401 indicates that the engine computer has identified that the flow rate of the Exhaust Gas Recirculation (EGR) system is inadequate, according to the manufacturer. In order to improve fuel economy, the EGR system sends a tiny portion of exhaust gases back into the intake. In this page, you may learn more about how the EGR system works.

What could cause the code P0401

– a clogged or defective EGR valve, as well as blocked or limited EGR channels A blocked EGR cooler, an EGR valve that is jammed closed, difficulties with the DPFE sensor (Ford), problems with the EGR hoses to the DPFE sensor (Ford), and an issue with the EGR vacuum switching valve are all possible (Toyota) -a catalytic converter that has been blocked A carbonized EGR temperature sensor, as well as vacuum supply problems at the vacuum pump -a malfunctioning EGR valve; -electrical issues with the EGR valve control circuit; -problems with the engine computer


– a blocked or defective EGR valve; – a clogged or limited EGR passage system; Troubleshooting the DPFE sensor (Ford) – difficulties with the hoses to the DPFE sensor (Ford) – troubleshooting the EGR vacuum switching valve (Ford) Troubleshooting the DPFE sensor (Ford) (Toyota) -a catalytic converter that has been obstructed vacuum supply concerns at the vacuum pump – a carbonized EGR temperature sensor – A malfunctioning EGR valve, electrical issues with the EGR valve control circuit, and computer issues with the engine are all possibilities.

Common problems:

EGR valve that has been clogged A blocked or stuck EGR valve is quite frequent in many automobiles, SUVs, and pickup trucks, as seen in the photo above. It is also possible that the EGR routes will be limited. The EGR ports in the throttle body become clogged on a regular basis. Ford: DPFE sensors that are faulty or damaged are one of the most prevalent problems that can result in the trouble code P0401 being displayed on many Ford cars (DPFE stands for Delta Pressure Feedback EGR). If the code P0401 on a Ford vehicle is being investigated, the DPFE sensor and the hoses that connect to the DPFE sensor are often inspected first.

  • When the vacuum is applied, it is expected that the voltage of the sensor signal would vary.
  • Sometimes simply replacing the DPFE sensor with a more recent model is all that is required to resolve the issue; however, other components of the EGR system must also be examined.
  • In the event that you are changing the DPFE sensor, make certain that the hoses are properly connected and are not crossed.
  • Honda/Acura: The code P0401 is commonly found in Honda V6 engines.
  • Other Honda Odyssey and Pilot models from 1999 to 2002, as well as select 2003 Honda Pilot vehicles, are affected by the same problem with the 3.5L V6 engine, which causes hesitation or surge under light acceleration, and which is indicated by the codes P0401 or P1491.
  • Acura V6 cars were also affected by the same problem.
  • Toyota Camry/Corolla: The Camry and Corolla are Toyota’s mid-size sedans.

The VSV is placed under the intake manifold at the back of the engine.

The repair technique is described in detail in this article.

Service bulletins are issued on a regular basis.

T-SB-0027-16 is a Toyota service bulletin.

It is stated in the Volkswagentechnical bulletin01 14 11 that the code P0401 (which might be followed by Fault P2463 DPF Soot Accumulation) can be caused by probable constraints in the EGR filter in select 2009-2014 vehicles with a 2.0L TDI engine.

The problem is described as follows: If this is confirmed, the warning recommends changing both the DPFEGR filter and the DPFEGR filter housing.

What needs to be checked with the code P0401:

The most typical issues with the exhaust gas recirculation system are a malfunctioning EGR valve and carbon deposits that are preventing proper EGR flow. It is necessary to test the EGR valve. There should be no carbon accumulation in the EGR cooler or channels, but there should be no limits. Testing an electronically-controlled ERG valve using a scan tool is simple: when the engine is idling, the EGR valve should be commanded OPEN on the scan tool and the engine should falter, run rough, or even stop.

Find out more about the EGR valve: its issues and symptoms, its testing, and its replacement.

Many mechanics recommend that you replace the EGR valve as well, because even if it is cleaned, the valve may become clogged.

It is also necessary to inspect the EGR sensor, which might be a DPFE sensor, an EGR temperature sensor, or an EGR boost sensor.

Ford Focus P0401: EGR – Insufficient Flow

P0401is a typical OBDII fault code that will appear in theFord Focus when the vehicle is started. It has anything to do with the emissions system and is abbreviated as: P0401: EGR Flow Is Inassailably Low The EGR system on a vehicle is in charge of recirculating exhaust gases in order to reduce the vehicle’s emissions production and reduce pollution. The EGR system on the Focus is composed of three major components. The EGR Valve, the Differential Pressure Sensor, and the Actuator Solenoid are the components in question.

Related: P0420 Ford Focus (Ford Focus)

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Ford Focus P0401 Symptoms

The majority of the time, when P0401 is triggered, there will be no symptoms other than the service engine light turning on quickly. If the situation is acute, you may hear a faint pinging or knocking sound.

  • The service engine soon light will be on when the code P0401 is entered. There may be a distinct knocking sound that emanates from the car under certain circumstances. It’ll sound nearly like a piston smack when it happens.

P0401 Causes: Ford Focus

In most cases, determining what is generating the P0401 error code in the Focus is not difficult to determine. The following are the most often seen reasons:

  • Blocked EGR Tube — Over time, the tube that transports exhaust gases back to the engine may get clogged with debris. It can also get twisted or kinked as a result of this. Particularly relevant if you are encountering P0401 shortly after doing engine maintenance. Examine the tube to see if it is fractured, blocked, or otherwise damaged
  • And In most cases, the EGR valve itself will not be the first location to look for issues with a vehicle’s performance. However, they are undoubtedly the root cause of P0401 on a regular basis. Engine Vacuum Issues – The EGR valve is dependent on engine vacuum to function properly. In other words, if you are seeing P0401 and other codes, it is possible that the P0401 is an indication of broader issues. As an example, if the motor is not operating properly in order to provide adequate vacuum to activate the EGR valve, the code P0401 will frequently be generated. Sensor Failure — The Differential Pressure Feedback-EGR sensor might become defective, causing the EGR valve to become inoperable and the code to be generated.

Focus P0401 Fix

The good thing about P0401 is that it almost never costs a lot of money to correct, and it is typically rather simple to identify the problem because it is located directly on top of the engine. The majority of people read P0401 Insufficient EGR flow and immediately search up the pricing of an EGR valve to see how inexpensive it is and simply replace it.

This may be a costly error. This is due to the fact that the EGR valve is not usually the source of the problem. Here are some of the most often seen solutions for resolving the P0401 error:

  • Check the EGR Tube- It’s a good idea to check the tube leading to the EGR because it’s commonly the source of the P0401 error code. It’s also a simple and quick procedure, and replacing it is quite inexpensive. Unless it’s cracked, you’ll have to get a replacement. If it’s clogged, you can get away with cleaning it and replacing it
  • Otherwise, you’ll have to replace it. Check the DPFE Sensor Voltage- If you are comfortable working with a voltage meter, go ahead and test it yourself. Here’s a nice post on how to do it from It Still Runs that can help you out: How to Perform a DPFE Sensor Test
  • Test the EGR Valve- A vacuum gauge can assist you in determining whether or not the EGR valve itself has failed. It can be tested using an avacuum gauge, according to this article from Autozone.


It is quite simple to do an EGR system test on your vehicle. The DPFE sensor proves to be the most difficult to work with. If you’re not certain in your ability to handle that, you can always try everything else first. It is possible to be reasonably certain that the DPFE is at fault based on the process of elimination. If you have anything to say about P0401 that you would want to share, please do so in the comments section below. Wishing you the best of luck!

P0401 Ford Vehicles

To learn more about the DPFE system in its entirety, please see the link provided below. This is a pretty frequent code seen on Ford automobiles, and it has the potential to drive people insane. Don’t be drawn into the trap of hurling components at the issue. It’s actually a very straightforward technique. According to the computer, it is necessary to determine whether or not the EGR valve is recirculating the amount of exhaust gas that was specified by the computer. The DPFE looks for a pressure change above and below a port in order to confirm this.

Failure to alter the engine speed or insufficient change can indicate a defective differential pressure relief valve (and there are a lot of those), a bad EGR valve (which is not as frequent), or passageways that are clogged with carbon buildup from the flow of exhaust gas (very common.) So, here’s how you troubleshoot the system in the first place.

  1. That is known as the basic voltage.
  2. The voltage should be shown as 5 volts.
  3. It should be between.45 and.60 volts (on the older metal-cased sensors).
  4. If you don’t notice those voltages, the DPFE is faulty and should be replaced.
  5. Ideally, it should be the same as when the engine is not running.
  6. That is not acceptable.
  7. 4) Vacuum the exhaust gas recirculation (EGR) with a hand-held pump.
  8. As the vaccum rises, the voltage rises in proportion.
  9. The absence of a greater voltage indicates that either the EGR is not opening (which you can check by removing it and applying vacuum) or the passageways are clogged.
  10. Then repeat test4 to determine whether you still have a rough-running engine after the first time.

If the engine is running rough but you are still not seeing greater voltage, then you need replace the DPFE in the engine. Rick Muscoplat was born in the year 2012. Rick Muscoplat posted a blog entry on


How to Fix a P0401 Code on Ford (Step by Step – Solved!)

Do you know how to troubleshoot a P0401 code on a Ford automobile? This is a question that a lot of our readers have for our writers. We’ve got you covered, believe it or not. Many Ford automobiles are infamous for having a very persistent P0401 code (Exhaust Gas Recirculation Flow Malfunction), which may be a stumbling block for many repair shops that specialize in other brands of vehicles, including those that specialize in Ford. Because the most common cause of this code on Ford vehicles is distinct from the typical suspects in other automobiles and trucks, this is the case in the majority of cases.

So, what is the best way to fix a P0401 error on a Ford?

  • First, inspect the DPFE sensor
  • Second, inspect the DPFE sensor tubes
  • Third, inspect the EGR ports
  • Fourth, inspect the EGR solenoid
  • Fifth, inspect the EGR valve

Meaning: What is the P0401 Code on Ford

The P0401 code indicates that the Exhaust Gas Recirculation Flow Insufficient Detected condition has been detected. EGR, or Exhaust Gas Recirculation, is a technology that reduces the quantity of nitrogen oxides (NOx) released into the atmosphere. Because NOx is created at extremely high combustion temperatures, a portion of the exhaust gases is recirculated back into the intake manifold to reduce NOx emissions. As a result, the amount of fuel-air mixture that can be held in a cylinder is reduced, which has the effect of decreasing the temperature of combustion in the engine.

The DPFE sensor is responsible for measuring this flow rate, and when it detects that there has been a significant decline in flow rate, the P0401 code is saved.

A diaphragm within the sensor is passed by the flowing gas, and this causes a weak electrical current to be generated, which the ECM interprets as the flow rate.

It will generate the code P0401 if the flow rate of the air coming into the EGR valve is insufficient.

Causes of the P0401 Code

The method by which EGR flow is monitored is the most prevalent source of inadequate EGR flow in the majority of Ford cars. The diaphragm within the DPFE sensor deteriorates over time, becoming less elastic. Even though the amount of gas flow remains constant, this results in the instrument measuring a steadily declining level of gas flow. It will eventually ‘report’ to the ECM that there is inadequate flow, despite the fact that there is ample flow. This is due to the lack of flexibility. As a result of this malfunctioning, the DPFE sensor will incorrectly signal the presence of an EGR flow issue.

It is important to note that exhaust gases contain a variety of combustion products, and they tend to gather on ports that are initially rather tiny.

The exhaust gases are extremely hot, and because the hoses are constructed of rubber, the continual heating and cooling of the rubber may eventually cause cracking.

The P0401 error code can be produced by a defective EGR valve solenoid, however it is usually never caused by the valve itself, which is extremely unusual. The three most common causes of P0401 on Fords are as follows: Take a look at the video below:

Diagnosis: Reading P0401 Code

P0401 is a standard ODB-II code that is found on virtually all cars that are compatible with the ODB-II On-Board Diagnostic standard. As a result, it is fairly simple to diagnose while driving a Ford vehicle with this code. All you need is any sort of ODB-II scanner to complete the task. It makes no difference whether you use a high-end professional all-in-one portable scanner or a low-cost Bluetooth scanner from eBay that connects to your phone. Depending on the specific kind, you will need to use the Scan button, which may be found either on the controls or within the software.

Troubleshooting P0401 Code on Ford (Step by Step)

When it comes to troubleshooting the P0401 code on a Ford vehicle, it all boils down to looking for the most prevalent reasons of the code. DPFE sensor must be checked in the first step. To do so, you’ll need a voltmeter with an attached back probe. After that, you’ll need to place it into the DPFE sensor connector on the right pin, which is one of three that it has, and then rejoin the connector with the rear probe. After that, you should switch the ignition key to the ON position but do not start the engine.

  1. If the reading is over that, the sensor is faulty and must be changed immediately.
  2. If the sensor voltage reading is satisfactory, you should proceed to the next step.
  3. To do this you will need to remove the throttle body and shine a flashlight into the intake manifold.
  4. 4th step: Inspect the EGR solenoid.
  5. To check this, you will need to separate both hoses from the solenoid’s two ports and attach a spare air hose to either of them, then just blow into it with your mouth.
  6. 5.
  7. It is necessary to replace the valve if the vacuum cannot be built up, or if it can be built up but subsequently fails to maintain its pressure.
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Prevent P0401 Code

The fact that the P0401 code will appear after a specific period of time in the life of your Ford car is a truth you must accept. The primary and most important reason for this is the limited life expectancy of the DPFE sensor’s diaphragm, which is estimated to last around 150,000 miles. As a result, if you want to avoid getting this code, you can change your transmission fluid every 140,000 to 150,000 miles. With regard to EGR port fouling, you may examine them every 50,000 miles or so and clean them if they are necessary.

This is another way to prevent the P0401 code from occurring. This is often the time of year when you should be examining any rubber hoses around your engine compartment for visible damage, so you may as well do it at this time.

Repair Cost of P0401

The cost of correcting the P0401 error code on a Ford vehicle is dependent on the specific source of the error message. If you take your vehicle to a professional shop, you may anticipate to pay between $100 and $150 in labor costs. You may expect to be charged for the following Ford parts, depending on the precise model and year of manufacture of your vehicle:

  • Prices for DPFE sensors range from $30 to $100
  • EGR solenoids range from $15 to $100
  • And EGR valves range from $70 to $500.

To put it another way, replacing any of these three pieces is quite straightforward and can be completed in less than 30 minutes if you want to do it yourself, saving you a few dollars in the process.


It is possible to lower the quantity of nitrogen oxides (NOx) in exhaust gases by inhibiting their creation during the combustion cycle with the help of an EGR system. This serves as a ‘cleaning’ measure for the exhaust emissions. When the DPFE sensor determines that there is inadequate flow of exhaust gases, the ODB-II code P0401 is generated. A low flow rate will result in increased NOx generation and, as a result, a failure to pass any future emission tests. It should be noted that when it comes to Ford automobiles, the most typical cause of the P0401 code is not a decrease in real flow, but rather a failure of the DPFE sensor.

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F150 EGR problem P0401,. solved

4.6-liter Ford F150 with 130,000 miles from 1997 My Check Engine light turned on last month, but nothing else appeared to be amiss with my vehicle. ‘Code P0401 EGR inadequate flow’ was the message I received after having the code scanned at AutoZone. I walked into the store and purchased an EGR valve. According to what I’ve been informed, it can take up to 100 miles for the computer to sample enough times to establish that everything is fine and turn off the light. The light went off for a short period of time before coming back on.

  1. It was said by Ford that this switch had been modified from a metal to a plastic version.
  2. After I had the code removed from the computer, the light turned on once more.
  3. After I cleared the code a second time, the light turned back on.
  4. I removed the pipe that was linked to the exhaust pipe and found that everything was in working order.
  5. It was the first time I’d ever seen a hole like that.
  6. So I took the trottle body off and, my, was I surprised!
  7. After thoroughly cleaning those two holes, it was discovered that they were somewhat larger than 3/8 inch holes.

I cleaned everything up and put everything back together. The issue has been resolved. I replaced more than $100 worth of parts and probably didn’t need to make any further changes at all. So if someone has been experiencing a recurring issue with the EGR code, clean out the throttle body! MrBill

P0401: Insufficient EGR Flow

The ability to troubleshoot issues is an important part of vehicle maintenance. When trying to figure out what is causing their cars to fail, DIYers may run across error codes that are new to them. P0401, which is generated by the on-board diagnostic system, is a puzzling yet often seen error code. Each of the symptoms and underlying reasons associated with an OBD-II scanner error code P0401 issue is listed below. In addition to providing clear direction on how to repair your car, understanding this code can also give some useful information.

What Does the Code P0401Mean?

It’s a good idea to examine the operation of the on-board diagnostic system before attempting to decipher what error code P0401 indicates. The use of OBD-II codes might provide additional information in the case of problems such as the check engine light. P0401 is a generic fault code that might be associated with the powertrain assemblies of your vehicle. The specific form of the problem might vary depending on the make and model of your automobile, but this code often indicates that your vehicle’s emissions system is experiencing a malfunction.

This system is comprised of an EGR valve, an actuator solenoid, and a differential pressure sensor, often known as a DPFE informally.

In layman’s terms, the EGR regulates how much of this pollutant is released into the atmosphere through your vehicle’s exhaust.

A severe fault has occurred, and it has to be corrected immediately.

What Are PotentialCauses of EGR Malfunction?

However, while your error code P0401 may not identify the specific reason of an EGR failure, it might indicate the general area in which you should begin investigating in order to diagnose and repair the problem. This sort of difficulty can be caused by a variety of factors, including:

  • EGR tubes that are restricted or blocked
  • A catalytic converter that has built up carbon
  • A faulty DPFE sensor
  • And a clogged catalyst converter. Vacuum supply to the EGR is faulty or non-existent. Electrical issues with the exhaust gas recirculation circuit
  • Issues with the engine computer

CommonSymptoms of P0401

A P0401 error code on your OBD-II scanner may or may not be accompanied by any symptoms in some instances. Your car, on the other hand, may display an illuminated check engine light. This error code is commonly associated with drivability difficulties like as pre-ignition banging or pinging, which are especially noticeable while driving at higher speeds. Additionally, you may notice additional symptoms such as surging, a loss of power, a reduction in fuel efficiency, stalling, or rough idling when the engine is running.

How Do IFix Trouble Code P0401?

Fortunately, you may resolve the underlying issues that might result in the occurrence of error code P0401. The most common option is to simply replace the EGR valve first, however this does not always resolve the issue.

It is possible that the error code will reappear even after the valve has been replaced. In order to make certain that you have addressed all of the probable reasons, follow these helpful diagnostic and maintenance steps:

  • Make use of a vacuum pump to open the EGR valve while keeping track of the engine’s rotational speed and DPFE voltage. When the EGR valve is open, there may be a perceptible difference in the RPM. Inspect and clean the EGR valve and tubing to ensure that any deposits are removed. Examine the voltage at the DPFE and compare it to the recommended levels. Pay attention to your owner’s handbook. Replace the DPFE sensor, ideally with a high-quality or original equipment manufacturer type
  • If the problem persists, the EGR valve should be replaced.

SolvingCommon Vehicle Problems

Failures of the EGR system can result in a variety of different sorts of vehicle issues. If left unaddressed, they can eventually result in engine performance difficulties as well as the breakdown of critical components. You can guarantee that you get back behind the wheel as soon as possible by purchasing your replacement components from your local AutoZone store.

Ford Explorer Questions – appear new code P0401 after code P0106

Ford: A broken or damaged DPFE sensor is one of the most prevalent faults that can result in the trouble code P0401 being displayed on numerous Ford cars (DPFE stands for Delta Pressure Feedback EGR). If the code P0401 on a Ford vehicle is being investigated, the DPFE sensor and the hoses that connect to the DPFE sensor are often inspected first. There should be no cracks or restrictions in the DPFE sensor and its hoses; the hoses should not be cracked or limited. When the vacuum is applied, it should cause a change in the voltage of the sensor signal.

While it is often possible to resolve the problem by replacing the DPFE sensor with an updated part, it is also necessary to examine the other components of the EGR system.

It is possible that the EGR valve is stuck or that the EGR passageways are obstructed; both of these problems are fairly prevalent.

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In the event that you are changing the DPFEsensor, make certain that the hoses are attached properly and are not crossed.

OBD-II Trouble Code: P0401 Insufficient EGR Flow

It is not possible to have enough exhaust gas recirculation (EGR).

What does that mean?

This diagnostic trouble code (DTC) is a general powertrain code, which means that it applies to any cars that are equipped with the OBD-II diagnostic system. Despite the fact that they are general, the particular repair processes may differ based on the make and model. Exhaust Gas Recirculation (EGR) is an abbreviation for this process. A component of the vehicle’s emissions system, it is responsible for lowering combustion temperature and pressure in order to manage Oxides of Nitrogen emissions.

The combination of these factors allows for the proper amount of recirculation to be delivered depending on engine temperature, load, and other factors.


It is possible to experience drivability issues, such as pinging (also known as pre-ignition knock), when the engine is under load or while the vehicle is traveling at higher speeds. There might also be other signs and symptoms.


A code P0401 most likely indicates that one or more of the following events has taken place:

  • This vehicle’s DPFE (differential pressure feedback EGR) sensor has failed and must be replaced. An obstruction in the EGR (tube), most likely caused by carbon buildup, has been discovered. The EGR valve is malfunctioning
  • It is possible that the EGR valve is not opening owing to a lack of vacuum

Possible Solutions

Quite frequently, when attempting to resolve this code, individuals simply replace the EGR valve only to have the OBD code re-appear.

The EGR valve is not necessarily the source of the problem.

  • Utilize a vacuum pump to open the EGR valve while keeping an eye on the DPFE voltage of the engine’s RPM. When the EGR is turned on, there should be a noticeable difference in engine speed. Remove any deposits from the EGR valve and/or tubing by cleaning them out. Check the voltage at the DPFE and compare it to the recommended levels (see a service manual for your individual model for further information)
  • Replace the DPFE sensor (with a high-quality / original-equipment sensor)
  • Replace the EGR valve if necessary.

P0400, P0402, P0403, P0404, P0405, P0406, P0407, P0408, P0409 are EGR codes that are related to each other.

Related DTC Discussions

  • P0401 on a 1997 Toyota Camry 4-cylinder CEL went off for a few weeks after I received the P0401 code for the first time a couple of months ago
  • I detached the battery to clear the code
  • The CEL came back on after a few weeks (including a 1000 mile round trip). I returned to work last weekend. EGR flow inadequate code is the same as before. I purchased a vacuum pump and gauge from AutoZone. On the 96 Grand Prix, at I P0401, I’m experiencing some difficulties with the code p0401. The EGR flow on my 96 Grand Prix was inadequate. I cleaned the intake and replaced the EGR valve, but the light continues to illuminate. I’m hoping someone can come up with a solution for me. PLEASE ASSIST!
  • Insufficient EGR Flow on a 1996 Toyota Corolla is code P0401. Hello there, everyone. What are your recommendations for the P0401 EGR Flow Insufficient code on a 1996 Toyota Corolla? Tks, bonnie *
  • 1997 Antarctic Expedition P0401 is a code that means ‘P0401 is a problem.’ Expedition with a 4.6 liter V-8 and 120k miles on the clock. My truck has had this code for quite some time, and I’ve been attempting to clear it. I’ve replaced the egr valve, the egr vacuum regulator, and the DPFE sensor with new components. I’ve tried everything: cleaning the carbon out of the intake ports, removing the egr tubing between the cylinders, you name it. P0401 code in conjunction with P0307 code I have a Ford E-350 van from 1998 with a V-10 engine. I had just recently observed that the engine was running rough, but there were no codes shown. It wasn’t until I reached the end of my driveway that the ‘check engine soon’ light finally illuminated. I already knew what it was because I had to change one of the coil packs
  • P0401, P1359, and P0420 PRULUDE 97
  • Earlier in the day. I just noticed that my check engine light was illuminated. It has the three messages listed above, yet the automobile functions normally. What is the best way to get these off? P1359 – DTC for a certain manufacturer The catalytic efficiency of the catalyst is below the threshold (PO420) (Bank 1) The EGR Flow is insufficient (PO401). What exactly is going on? In English, this would be: 96 Ford Taurus with P0401 error code Hello everyone, I’m writing to express my gratitude for your time and consideration. It would be really appreciated if anyone could assist. P0401 ‘EGR Flow Insufficient’ on my 1996 Ford Taurus V6 24V OHC will not clear, and I have tried everything to fix it. I changed the EGR valve on my vehicle. The code has been returned. I discovered that the EGR vacuum regulator solenoid had come loose from its mounting bracket and had fallen behind the engine, which was linked to the
  • P0401 Honda Accord V6 2000
  • I also had a query concerning the transmission. Greetings, one and all! I’m glad I came into this interesting forum. It happened to me that the check engine light turned on in my 2000 Honda. P0401 EGR Flow inadequate was the error code Honda sent me. I wish I had known about Autozone running the codes earlier, but Honda charged me 65$ for doing so! Well, that’s life. Even with 86,000 miles on the odometer, the prolonged emissions were
  • Help, P0401 is causing me fits! I’ve replaced the EGR valve and sensor, but the error would not clear even after that! Any suggestions to assist me? My inspection is currently two months overdue. Thanks
  • 96 Saturn P0401 An EGR inadequate flow code of p0401 has been thrown at me. I replaced the EGR valve twice, with two different manufacturers, and the problem persisted. I can scope the blue wire when the egr is unbolted from the intake (with the vac port connected in) and it displays the command to open in stages. Using a scope on the brown wire (return), I can see that the valve is opening. A

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P0401 – Meaning, Causes, Symptoms, & Fixes

It was discovered that the exhaust gas recirculation (EGR) flow was insufficient.

Code P0401 Meaning

In order to lower the combustion temperature and, as a result, reduce the generation of smog-forming nitrogen oxides, the exhaust gas recirculation (EGR) system returns tiny volumes of exhaust back into the combustion chambers of the engine. EGR valves can become jammed open or closed as a result of carbon buildup, causing them to malfunction. When the issue code P0401 is set, CO2 is reintroduced into the combustion chamber at an improper time or in an inaccurate amount, resulting in the combustion temperature not being reduced sufficiently to avoid the increase in NOx.

Symptoms of Code P0401

  • Check Engine Light on
  • Failed emissions test
  • Slower acceleration
  • Pinging at the start of the engine

Causes of Code P0401

  • Clogged or blocked EGR passageways owing to an overabundance of carbon in the exhaust gas
  • EGR valve that is not functioning properly
  • EGR temperature sensor that is coated with carbon

Code P0401 Severity – Moderate

Exceedingly carbon-laden EGR passageways clog or become constricted. Incorrect operation of the exhaust gas recirculation valve; carbon accumulation on the EGR temperature sensor;

Code P0401 Common Diagnosis Mistakes

Replacing the exhaust gas recirculation (EGR) valve without first inspecting the air passages of the intake manifold or the temperature sensor

Code P0401 Diagnosis Steps

  • Throttle body cleaning, speedometer cable, ratchet and socket set
  • FIXD

How To Diagnose P0401

  1. Look for leaks in the vacuum hoses and wiring, as well as any other connections to the EGR valve that might be causing air flow to be diverted away from the intake manifold. Any of these connections should be replaced if you discover corrosion or fractures in them. This will also clear your check engine light. Use your car’s service manual to identify and inspect the vehicle’s EGR temperature sensor for any carbon buildup that might cause the sensor’s readings to become inaccurate. Using the speedometer cable and throttle body cleaner, remove the carbon buildup. Locate and inspect the EGR valve for carbon buildup according to the instructions in your car’s service manual. For a visual reference, have a look at this video. Use a speedometer cable and throttle body cleaner to remove any carbon buildup that may be obstructing any air channels if you see carbon accumulation. Locate and remove the intake manifold according to the instructions in your car’s service manual to inspect for carbon buildup. Take a look at this video for some visual inspiration. Disconnect any hoses that are attached to the intake
  2. The air intake pipe that is linked to the throttle body should be disconnected. Take out the throttle body. Eliminate the intake manifold to check for carbon accumulation
  3. Clean the intake manifold with the speedometer cable and throttle body cleaner to remove carbon buildup. Reinstall the intake manifold and all of its hoses, as well as the throttle body and other components. If following these procedures does not resolve your Check Engine Light problem, you may need to take your vehicle to a repair since there may be internal electrical problems with your vehicle.

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