P0401 P1408 — Ford?

  • Fords with P0401, P1408 trouble code are known for problems with their DPFE sensors. These sensors detect the change in manifold vacuum pressure when the EGR is commanded on and off and display P0401, P1408 trouble codes. If you get an EGR code, DO NOT automatically assume that it’s a bad EGR valve!

How do I fix code p1408?

Start with the EGR valve; remove and clean the EGR valve pintle rod, and at the same time, clean the opening of the EGR port where the valve is mounted. If you can, clean the passage that goes downstream from the port up to the throttle body.

How do I fix code P0401?

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 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.

How do you know if the DPFE sensor is bad?

When the DPFE sensor fails, the engine can’t run as it was designed. In fact, engine performance issues are the first sign that something is wrong with this sensor. With a faulty sensor, the wrong information is sent back to the engine’s computer. Because of this bad data, the EGR system malfunctions.

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 much does it cost to fix P0401?

P0401 Repair Costs Code P0401 warns of problems with your EGR system, from a faulty valve to a dirty temperature sensor. The severity of the problem varies depending on the extent of the components affected. Total repair costs range from $150 to $750, inclusive of labor and parts.

Can a bad catalytic converter cause an EGR code?

A bad catalytic converter wouldn’t in itself cause a misfire code, but if the cat. is partially blocked then exhaust gas flow will be impeded and that can cause an engine to misfire if all the old exhaust gas isn’t able to escape the cylinder before the new air/fuel charge is sucked in.

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 DPFE sensor Ford?

DPFE (Differential Pressure Feedback Electronic) Sensors are an integral part of the EGR (Exhaust Gas Recirculation) System. The DPFE Sensor provides information to the Powertrain Control Module (PCM) to tell it how much exhaust gas is flowing through the system.

P0401 P1408 — Ford

DPFE sensors have been known to fail in Fords with the P0401 and P1408 fault codes in the past. If there is a change in manifold vacuum pressure between switching on and off the EGR, these sensors detect it and display the fault codes P0401 and P1408. If you receive an EGR code, DO NOT instantly conclude that the EGR valve is faulty! Use a hand-held vacuum pump to apply suction to the exhaust gas recirculation (EGR). Check to see if the valve is working properly. If it moves freely and the channels are free of debris, go to the DPFE sensor for inspection.

While you’re doing this, keep an eye out for any changes in voltage.

Remove the throttle body and gasket from the engine.

It is quite possible that you will notice that the channels have become blocked with carbon accumulation.

After that, replace the gasket as well as the throttle body.

This issue is frequent on the 2.5, 3.0, and 4.6 liter Duratec engines, as well as the 4.6 liter engine.

Rick Muscoplat posted a blog entry on

Read further: P0401 P1408 — Ford?

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

Symptoms

– 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.

Code P0401.

Code P0401. Hello everyone, I’m attempting to figure out what is causing a P0401 error number. Okay, here’s what the code says in its entirety. Insufficient EGR Flow was detected, which resulted in the code P0401. During steady state driving circumstances, the EGR system is monitored while the EGR is turned on and off as needed. When the signal from the DPF EGR sensor indicates that EGR flow is less than the specified minimum, the test is considered to have failed. Possible Causes Supply of Vacuum The EGR valve has become jammed closed.

  • The EGR flow channel has been reduced.
  • VPWR is connected to the EGRVR solenoid.
  • Hoses for the DPF and EGR sensors have been reversed.
  • If P1408 isn’t present, examine for contamination, limits, leaks, and intermittents to rule out other possibilities.
  • In light of the code information and the fact that the EGR is not the source of the problem, does anyone know if a broken Catalytic Converter may be the reason of this code?
  • However, after speaking with a few folks, I’ve learned that some welding may be required in order to replace the catalytic converter (CAT) valve.
  • This error number began appearing a few months after the spark plug replacement.
  • as well as a search for ‘cata’ I came across the P0420 code, which is a few codes down, and was intrigued by the statement that a catastrophic misfire might result in catalyst damage.
  • Assuming that’s the case, can we safely conclude that the faulty spark plugs and wires were to blame?
  • TIA!
  • 1) Does anyone know what else may be triggering the P0401 code?

2) Are the terms catalyst and catalytic converter interchangeable? No problem2 – I discovered the solution in the FAQ section of the website. If a damaged catalyst is suspected as the source of the P0401 error code, what are the chances of this happening?

Better Breathing: EGR Improvements

So, what is the purpose of EGR? More information is available by clicking here. Glen Beanard, technical contributor, contributed to this article. During the early 1970s, the Exhaust Gas Recirculation (EGR) system was developed for the same primary reason that drives the design of every other engine management system: to minimize emissions. The EGR valve is designed to target a specific pollutant, nitrogen oxides (NOx). The oxygen (O2) in the air and hydrocarbons (HC) in the fuel mix to form water (H2O), but carbon dioxide (CO2) and nitrogen stay unaltered during normal combustion.

  1. At high temperatures, oxygen and nitrogen begin to combine with one another to generate nitrogen oxides (NOx).
  2. When this occurs, we are confronted with pollution.
  3. By lowering the temperature of the combustion chambers to a level where regular combustion may occur.
  4. Temperatures in the cylinders can be lowered by many means, including increasing the quantity of ethanol in the fuel mixture, decreasing compression ratio, delaying the ignition timing, lowering the overall engine temperature, and decreasing clean air intake and exhaust.
  5. Additionally, all of those, with the exception of one, will increase HC emissions.
  6. What is unexpected, however, is that this not only solves an issue, but it also has the additional benefit of increasing efficiency.
  7. So, how are we going to ‘water down’ the air mass, you may ask.
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Because the air entering the engine includes oxygen, it is conducive to combustion and therefore requires a specific quantity of fuel to be combined with it.

We’re searching for something that doesn’t support combustion and doesn’t require a specific amount of fuel to be burned in the cylinder to function properly.

Rather of modifying the engine, let’s just install a pressurized cylinder under the hood and inject a little amount of either of those gases into the intake to dilute any fresh air entering the cylinders.

For as long as they are inert, this would be the case for a variety of other gases as well.

Our tank would get pressured, and we’d have to keep replenishing it with fresh water.

All that has to be done now is to devise a method of redirecting part of this back into the intake manifold, which is currently impossible.

Theoretical and practical considerations Gains in efficiency have already been stated; how does EGR contribute to increased efficiency?

The inclusion of the EGR gases shortens the duration of the burning process.

But what about the decrease of ‘pumping losses’?

The EGR valve acts as a second ‘breathing’ supply for the piston, allowing it to operate more efficiently.

In this instance, the driver will have to open the throttle plate a bit wider than he or she would have to if the vehicle did not have an EGR system installed.

As a result, the engine’s efforts to ‘pump’ the air into the cylinder are decreased as a result of this modification.

For those who find it difficult to visualize this, consider how some engines may benefit from the use of twin exhaust systems.

This is due to the fact that dual exhaust can minimize pumping loss by allowing for a less restrictive exhaust stroke to be used.

EGR has the same impact on the intake stroke because the driver opens the throttle plate farther, which effectively decreases the intake restriction, which in turn lowers the pumping losses on the intake stroke, which is the same effect as on the exhaust stroke.

So, how does it cool the cylinder when the intake air charge is really heating it?

During the intake stroke, there is no cooling activity taking on at all.

Consider the following for a moment: Consider the following scenario: a campfire with five logs blazing.

The logs are attempting to communicate with one another.

A tendency for the fire to spread at its own pace will be present as well as a high concentration of heat energy between the logs.

What would happen to the fire if this happened?

Furthermore, and maybe most crucially, the fire can now be contained.

It was decided to let the fire burn at its own pace.

That is the fundamental idea behind the cooling effect of the EGR gases on the combustion chamber.

As a result of enhanced control over the burning activity in the cylinders, it is now possible to advance the ignition timing in order to take use of the increased energy created.

Figures 2 and 3 show a close link between EGR flow, Timing Advance, and Engine Load, which is particularly noteworthy.

The opening of an EGR can be controlled by a vacuum control or an electrical signal, for example.

Similarly, the methods of sensing and manipulating this valve differ from one vehicle to the next.

Even while much of this talk will be limited to Ford vehicles, some of it may be applicable to other automobiles as well.

Ford DPFE and PFE EGR Systems in their most common configuration The EGR valve in this sort of EGR system is pneumatically controlled by the PCM through the use of an EGR control solenoid, also known as an EVR (EGR Vacuum Regulator).

According to the ‘on’ time duty cycle existing at the EVR’s ground, the EVR pulses vacuum (up to 7 inches) to the EGR.

The resistance measured through the EVR’s windings should be between 26 and 40 ohms in value.

If there is an open or short in the circuit to the EVR, the PCM will set the fault codes P0403 and/or P1409, depending on the severity of the problem.

The letter ‘D’ in DPFE is also referred to as ‘Delta’ in some circles.

The PFE was an early form of what we now refer to as a DPFE.

Due to characteristics like as age and volume, it is, nevertheless, currently the most prevalent type of damage dealt with in repair shops at the moment.

The EGR supply tube has been modified to include a restrictive orifice in order to accomplish this result.

Whenever the EGR valve is closed, there is a balance between pressures on both sides of the orifice.

The DPFE is responsible for monitoring both sides of the orifice, whereas the PFE was solely responsible for monitoring the downstream side.

The signal wire has a voltage of 5 volts on it, which is the same voltage as the 5-volt reference wire has on it.

In some older models of DPFE sensors, the signal voltage might decrease to as low as 0.5 volts while the sensor was at rest.

The voltage of the signal then rises, and the voltage indicated on the DPFE PID climbs with it.

The PFE, the DPFE’s older brother, performed the identical functions as the DPFE, with the exception that the voltage-to-pressure connection was the opposite of the DPFE.

As the PFE sensor identified the presence of EGR flow, the signal voltage began to fall.

Every time the engine is at idle, the PCM checks for flow through the DPFE, and there should be none, of course.

This can be caused by a stuck EGR, a stuck EVR, or by erroneously reading the DPFE, among other things.

If the PCM judges that there is insufficient exhaust pressure available at the upstream hose, it will set the code P1405 to indicate that there is no exhaust pressure available.

Whenever the PCM detects that the system is not operating properly, it will put the fault code P0401 or P1408 on the system bus (reserved for KOER self test only).

When the necessary criteria are satisfied, this test is repeated indefinitely.

In order to go from totally closed to fully open, it has 52 increments (steps) that are controlled directly by the PCM.

As soon as the EGR valve is opened, the Temperature Manifold Absolute Pressure (TMAP) sensor detects an increase in manifold absolute pressure (or a decrease in manifold vacuum), as well when a rise in the temperature of the air charge within the manifold, as the EGR valve is opened.

In some applications, temperature sensing serves as a second IAT sensor in addition to the first.

The MAF sensor is still in use for load calculations on this car.

A P0400 is set if the PCM senses an excessive or insufficient amount of flow.

The PCM keeps track of the circuitry that connects the EGR valve to the EGR coil drivers.

A short or open circuit will be detected by the PCM and the code P0403 will be set.

ESM System is an abbreviation for Electronic Security Management System.

It combines the functions of an EGR valve, an EVR, a MAP sensor, and a DPFE sensor into a single unit.

Despite the fact that the DPFE sensor on an ESM is referred to as ‘DPFE’ by the scan tool and wiring schematics, it is not the same as the classic DPFE sensor that was utilized on the previous EGR system.

In order to monitor EGR flow, one MAP sensor is installed after the EGR valve seat and before the flow restrictor integrated into the base gasket of the EGR valve.

The MAP sensor, which is responsible for sensing manifold pressure, has a role that is significantly more complex than just assisting in the calculation of EGR flow.

While this is true, it does not imply that BARO is only derived from the MAP sensor.

At KOEO, however, the BARO will be modified to accommodate the MAP sensor located in the engine management system (ESM).

Take a look at Photo 1.

It goes without saying that the following step is to check the DPFE voltage and to perform a flow test on the EGR ports.

Make use of your scan tool to pull up the DPFE PID information (you can also use a volt meter on the DPFE signal lead).

Keep an eye on the DPFE voltage and pay attention to the engine.

Depending on what happens, the next step will be determined by the outcome.

The engine made a little stuttering sound every so often.

On the data capture, take note of the DPFE voltages and the small fluctuation in the engine rpm readings.

If there is no change in DPFE or engine rpms at all, it is likely that the EGR has been totally shut down or that the EGR valve is not opening owing to a damaged line, a malfunctioning EVR, or a lack of B+ to the EGR.

Testing for the existence of the orifice may be accomplished by attaching a vacuum gauge to the upstream DPFE pipe while leaving the EGR completely open.

Don’t forget to include the PCM’s ability to open the EVR and read the DPFE in your test results, regardless of whether you’re using a scan tool or not while conducting this testing.

Following that, the EGR system was retested in the same manner as it had been before.

The following car is a Ford Contour, which is powered by a 2.5L engine.

Because the DPFE sensor is stuck at 2.86V (as seen in Figure 10), the following test will need to be slightly changed.

It is possible to do flow testing by inserting a vacuum hose into an upstream pipe and listening to the engine run.

After that, the vacuum hose is disconnected from the EGR valve, and the valve is listened for as it slams shut with an audible ‘slap.’ The ‘slap’ of the EGR valve is audible, indicating that it was really opened.

When the throttle body is removed for cleaning, it is discovered to be entirely blocked up with debris.

The corridors have been thoroughly cleaned (see Photo 3).

Take a look at Figure 11.

As an example, consider an E-250 van with a 4.2L engine.

The complaint said that the Check Engine light was illuminated and that the engine misfired.

As soon as the engine was gingerly loaded into the bay, the engine began to skitter violently.

Only a peak DPFE voltage of 1.5 volts was discovered after increasing the flow rate through the EGR ports.

Except for the third cylinder, all of the EGR ports were limited.

As a result, the third cylinder became swamped with more EGR gases.

I hope that some of the material presented here will help you gain a better knowledge of the EGR system and that it will be of value to you in the future as well.

In a recent announcement, Sinochem Modern Environmental Protection Chemicals (SMEPC) of Houston, Texas, stated that it intends to manufacture new, proprietary fluorochemicals for refrigerants that will meet the European Union (EU) F-Gas requirements for reducing the global warming potential (GWP) of refrigerants used in future automotive air conditioning systems.

In the words of Michael Marshall, director of sales and marketing for Sinochem USA, ‘Sinochem aspires to position itself as a major supplier to the worldwide mobile automotive air-conditioning sector through the delivery of high-quality products that match current and future industry expectations.’ Chinese company Sinochem manufactures fluorochemical refrigerants in two manufacturing facilities in the city of Xi’an.

Another fluorochemical complex with a research and development center is now under construction outside Shanghai, China, and is expected to be operational by the end of the year 2007.

In order to build a comprehensive range of fluorochemical goods, the research and development center will be dedicated to this goal. Contact Sinochem USA, Inc. at 713-686-0700 if you require further information or assistance.

6 Most Common Problems with Ford 4.6L Engine

So, what is the purpose of EGR in the first place? Read More by visiting this link: Technical Contributor Glen Beanard’s article During the early 1970s, the Exhaust Gas Recirculation (EGR) system was developed for the same primary motive that drives the design of every other engine management system: to minimize emissions. A specific pollutant, nitrogen oxides, is targeted by the EGR valve (NOx). The oxygen (O2) in the air and hydrocarbons (HC) in the fuel mix to form water (H2O) in a typical combustion process; the carbon dioxide (CO2) and nitrogen stay unaltered.

  1. Nitrogen and oxygen begin to combine at certain temperatures, resulting in the formation of NOx.
  2. The result is smog, which is a pollutant.
  3. In order to allow proper combustion to occur, the combustion chambers must be cooled.
  4. Temperatures in the cylinders can be lowered by many means, including increasing the quantity of ethanol in the fuel mixture, decreasing compression ratio, delaying the ignition timing, lowering the overall engine temperature, and decreasing clean air intake and output.
  5. In addition, all of those, with the exception of one, will increase HC emissions in the environment.
  6. Interestingly, this not only resolves the issue at hand, but it also has the added benefit of increasing efficiency.
  7. So, how are we going to ‘water down’ the air mass, you might wonder.
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It is necessary for a specific quantity of gasoline to be combined with the air that enters the engine because it includes oxygen, which promotes burning.

A substance that does not promote combustion and which isn’t dependent on a specific amount of fuel to be burned in the cylinder is what we’re looking for.

In order to mitigate the effects of the fresh air entering the combustion chambers, let’s just install a pressurized container under the hood and inject a little amount of either of the two gases into the intake system.

For as long as they are inert, this would be the case for a number of other gases as well.

Our tank would get pressurized, and we’d have to keep replenishing it with fresh fuel.

What has to be done now is figure out how to reroute some of it back into the intake manifold, which should not be too difficult to do.

Theoretical foundations and practical applications It was indicated before that efficiency gains are possible; how can EGR contribute to increased efficiency?

Adding EGR gases reduces the amount of time it takes to complete a burn.

But what about the decrease of ‘pumping losses’?

This second ‘breathing source’ for the piston is provided by the EGR valve.

In this instance, the driver will have to open the throttle plate a bit farther than he or she would have to if the car did not have EGR.

A result of this is that the engine has to work less to ‘push’ air into the cylinder, which saves on energy.

For those who find it difficult to visualize, consider how some engines may benefit from the use of dual exhaust systems.

This is due to the fact that dual exhaust can minimize pumping loss by allowing for a less restrictive exhaust stroke to occur.

Due to the driver opening the throttle plate farther on the intake stroke, EGR has the same impact as on the exhaust stroke.

In comparison to fresh intake air, EGR gases are hotter.

In this case, it isn’t important what temperature the air charge is at.

This occurs during the power stroke, and it is accomplished by regulating combustion pressure.

It is best to arrange the logs in a pyramid arrangement with three logs on the bottom and two logs on top.

Because the logs are sharing heat energy with one another, while a fire is burning in this manner.

Assume that the identical logs are used again, but this time they are separated by a fog machine.

The second fire between the logs will not be as hot as the first one because of the difference in temperature between them.

There was no control over the first fire example.

In order to maintain control over the second one, the amount of fog pumped into it must be varied; as such, it is not let to run amuck.

The EGR gases disperse the air and fuel molecules, preventing them from burning as quickly and as hotly as they would otherwise be permitted to.

One further efficiencies gain will be realized at this point.

A few specifics differ from one vehicle to another, despite the fact that the main function and operation are the same across all models.

The EGR valve may ‘dump’ all of its gases into the intake plenum through a single port, or it may disperse a modest quantity of gases into each of the separate intake runners feeding the cylinders through a series of port locations.

For the sake of this section of the discussion, Ford EGR systems will be used as examples.

Always be sure to check information unique to the make and model of your vehicle before attempting any diagnostics or repairs.

The EGR valve in this sort of EGR system is pneumatically controlled by the PCM through the use of an EGR control solenoid, also known as an EVR, which is located in the EGR control circuit (EGR Vacuum Regulator).

Upon detection of a duty cycle of ‘on’ time existent at the EVR’s ground (see Figure 4), the EVR pulses vacuum (up to 7 inches) to the EGR.

When the EVR is turned on, the PCM performs electrical continuity tests on it.

Differential Pressure Feedback EGR sensor is abbreviated as DPFE.

‘Change’ is a Greek word that literally translates as ‘delta.’ It is also accurate.

The DPFE is a more recent innovation than the PFE, although it is not the most recent kind of EGR flow monitoring technology available today.

Pressurization decrease is monitored by the DPFE and PFE systems.

Figure 5 shows an example of this.

Although when the EGR valve opens, a pressure drop happens on the downstream side of the aperture as a result of the gases flowing through the valve.

When reading the DPFE, the PCM employs a voltage drop technique.

The DPFE reduces this voltage to 1.0 volt while the device is at rest.

Its internal resistance rises when the DPFE detects a change in pressure across the orifice.

There are roughly 4.8 volts detected at an infinite resistance on the signal cable.

At-rest voltage was extremely high in the instance of a PFE (usually around 3.5 to 4.0 volts).

The electrical circuits of the DPFE are checked, and if an electrical problem is detected, the fault codes P0405, P0406, P1400, and/or P1401 may be set, respectively.

As a result of excessive DPFE voltage, the PCM will set the error code P0402, which indicates that EGR is flowing.

One time every driving cycle, the PCM inspects the exhaust pressure existing on the upstream DPFE pipe to see whether there are any limitations or if it is torn.

The PCM monitors the flow via the EGR system while the vehicle is travelling at a constant speed and the EVR duty cycle rate is high.

EGR restriction, damaged vacuum lines to and from the EVR, a mechanically defective EVR, a stuck EGR valve, or an incorrect reading of the DPFE are all possible causes.

Electronic Gearbox (EGR) for Stepper Motors In contrast to the stepper motor EGR, which is mechanical, the stepper motor EGR is electrical.

Figure 6 shows an example of this.

The PCM interprets variations in manifold pressure as changes in the amount of EGR flowing through the exhaust system.

(See Figure 1).

In order to calculate load on this car, it still requires a MAF sensor.

An error code P0400 is generated if the PCM detects excessive or insufficient flow.

Using the EGR coil drivers as input, the PCM checks the circuitry leading to the EGR valve.

A short or an open circuit will be detected by the PCM and the code P0403 will be generated.

ESM System is an abbreviation for Electronic Security Management System (ESM System).

A combination of an EGR valve, an EVR, a MAP sensor, and a DPFE sensor is included within a single unit.

Despite the fact that the DPFE sensor on an ESM is referred to as ‘DPFE’ by the scan tool and wiring schematics, it is not the same sensor as the one used on the earlier EGR system.

In order to monitor EGR flow, one MAP sensor is installed after the EGR valve seat and before the flow restrictor integrated into the base gasket of the EGR system.

The MAP sensor, which is responsible for monitoring manifold pressure, performs a role that is significantly more complex than just assisting in the calculation of exhaust gas recirculation.

This does not imply that BARO is completely derived from the MAP sensor’s readings, though.

At KOEO, however, the BARO will be modified to accommodate the MAP sensor located in the engine management system (EMS).

Take a look at Image 1.

The question is, what are you supposed to do?

Fortunately, all of this can be accomplished in a single convenient exam.

Then, from the bidirectional controls menu of your scanner, pick the EVR and set the EGR to 100 percent (if you are not using a scan tool, ground the EVR solenoid).

For example, in one stage, we are checking for leaks and checking for EVR, EGR, vacuum to and from EVR, DPFE sensor, and orifice within the EGR supply tube.

In this particular instance, the EGR valve did open, and the DPFE registered a little amount of flow through the system.

Figure 8 shows one example of this.

A constrained EGR is inferred from this.

The DPFE may be malfunctioning, or the opening in the EGR supply tube may be missing, in which case the engine may have stopped or stumbled badly yet there was no change in the DPFE value.

On a free-flowing EGR with a decent aperture in the tube, that hose should normally have a measured vacuum of 5 to 10 inHg.

Figure 9 depicts the removal of the vehicle’s throttle body and the cleaning of the EGR ports.

Take note of the DPFE readings from a clean EGR system, as well as the disturbance in the engine’s operation produced by the clean system.

P0401 is the trouble code that has been assigned to the vehicle.

Just like in the previous scenario, the EGR valve is ordered at full capacity.

There is no discernible difference in the operating condition of the engine, and the vacuum indicator scarcely moves from its 0 position.

An audible ‘slap’ is heard, indicating that the EGR valve opened.

During the course of cleaning the throttle body, it is discovered to be fully blocked up.

As shown in Photo 3, the corridors have been cleaned.

Figure 11 shows an example of this.

As an example, consider an E-250 van with a 4.2L engine, which presents a new set of problems.

P0401 and P0303 were the trouble codes that were discovered (cylinder3 misfire).

With the EGR valve closed, the engine’s misfiring was halted by using the scan tool to tell it to do so (a non-scan tool method would be to unplug either the EGR valve or EVR).

Upper plenum was removed so that it could be thoroughly cleaned.

Photo 4 illustrates this.

It would misfire on that cylinder if that cylinder was overburdened.

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Common Problems

Failures of the spark plug or ignition coil are the most prevalent causes of the check engine light being on together with misfire codes p0300 – p0308. If you are experiencing the P0300random misfire or undetected misfire, Ford has issued a powertraincontrol module update that will resolve the issue. CLICK HERE FOR MORE INFORMATION.

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2. Injector Problems

There have been a few reports of injectors being clogged or becoming stuck open, resulting in P0172 or P0175. Reading fault codes through the OBD-IIport reveals that the fault codes indicate defective oxygen sensors, which is what you’re looking for. It is not uncommon for injector difficulties to be misdiagnosed as oxygen sensor problems. The PCM receives information from the oxygen sensors about what they are sensing. These codes are generated by the management system to indicate that the exhaust is too rich or has exceeded its limit.

  1. That is a telltale symptom of a leaky inj sensor issue in the making.
  2. These codes are generated by the management system to indicate that the exhaust is too rich or has exceeded its limit.
  3. That is a sure indicator that the injector is leaking.
  4. It is possible that the driver may notice high backpressure, check engine light flashing, and poor engine light flashing, along with poor performance, at some point.

3. Fuel Pressure Regulator

Fuel pressure regulators that are mounted on the gasoline rail have the potential to leak raw fuel through their supply vacuum port. If you suspect a faulty fuel injector or a faulty regulator, you may do a leak-down test with a fuel pressure test gauge or a diagnostic scanner that can run an injector test with a diagnostic scanner. This is a potential fire danger. Precautions should be taken, otherwise this should be handled by a professional. If you have one that has melted or if the sensor has melted, be sure to get the exhaust system examined for high backpressure before continuing.

4. Exhaust Gas Recirculation Problems

It is possible for the exhaust gas recirculation system to malfunction and generate the following codes:

  • 1408: EGROut of the Self-Test Range A problem with the exhaust gas recirculation (EGR) flow has been detected (P0401).

Generally speaking, the codes p1408 or p0401 refer to the exhaust gas recirculation system. The P0401 error code was often caused by a defective DPFE sensor (EGR pressuredifferentialsensor). Alternatively, the DPFE sensor might become contaminated with moisture from condensation in the exhaust system and fail, or the hose from the exhaust bleed fitting could come loose or melt completely.

5. Oil leaks

On the whole, the Ford 4.6L engine does not suffer from significant oil leaks. Leaks from the valve cover gasket or the front crankshaft seal occurred on occasion.

It was also possible to find a Ford 4.6L engine in a police interceptor; however, the oil coolers on these vehicles frequently leak externally or into the cooling system. The cooler was replaced, and the cooling system was chemically flushed, which took care of the problem.

6. Front cover noises

Maintenance on timing chains, guides, and tensioners would fail if it was not performed at the appropriate intervals. Oil changes with a filter, as well as simple common sense, would keep this engine running for a lengthy period of time. If you want to maintain it operating smoothly, it’s highly advised that you use good fuel. Always keep in mind that it is not required to use higher-octane gasoline. Any car equipped with a Ford 4.6L engine is capable of lasting for an extended period of time.

In a Lincoln Town Car or Ford F-150, an odometer reading in the 250,000-300,000 range is not unheard of.

Applications

  • Maintenance of timing chains, guides, and tensioners would be ineffective if it was not performed at the appropriate times. Oil changes with a filter, as well as common sense, would keep this engine running for a very long time! If you want to maintain it operating smoothly, it’s highly advised that you use excellent gasoline. Always keep in mind that using a higher-octane gasoline is not mandatory. Any vehicle powered by a Ford 4.6L engine is capable of lasting for an extended period of time on the road. Numerous such devices are placed in police interceptor vehicles, where they are frequently used for an extended period of time. In a Lincoln Town Car or Ford F-150, an odometer reading in the 250,000-300,000 range is fairly uncommon. All things considered, Ford’s 4.6L engines are quite reliable.

Specifications

Metric Value
Engine family Modular
Displacement 4.6 liters
Aspiration Atmospheric
Configurationcylinders V configuration, eight cylinders
Vehicle engine orientation Longitudinal
Valve configuration Singleoverhead cam(SOHC) / Dual overhead cam (DOHC)
Assembly sites Romeo, Michigan, USA / Windsor, Ontario, Canada
Predecessor Ford small-block V8
Successor Ford Coyote engine
Bore 90 mm
Stroke 90 mm
Compression ratio 9.0:1 (2 valve) / 9.4:1 (3 valve) / 8.5:1 (4 valve)
Max power @RPM(in a Ford vehicle) 390 @ 6,000rpm
[email protected] RPM (in a Ford vehicle) 390 lb-ft @ 3,500 rpm
CylinderHead Aluminum
Cylinder Block Cast iron / Aluminum (depending on the version)
CamshaftDrive Chain

2012 Ford F-450 OBD2 Code P0401 Exhaust Gas Recirculation A Flow Insufficient Detected

P0401 is characterized as an InsufficientEGRFlow in the OBD-II system.

P0401 Symptoms

  • Check There will be an illumination of the engine light. In the vast majority of situations, the driver is not aware of any hazardous conditions. It is possible to have performance issues, such as pinging while the vehicle is being driven at greater speeds or when under stress, when the engine is being used.

Consult with a medical practitioner to determine the cause of the problem.

Common Problems That Trigger the P0401 Code

  • Excessive carbon buildup in the EGR passageways is the most common cause of restriction. The EGR Valve is not working properly
  • An insufficient vacuum or electrical signal to the EGR valve is present. EGR Vacuum supply solenoid that is not working properly
  • Inadequate EGR system feedback to the computer from the following sources:
  • Absolute pressure sensor in the manifold
  • Differential EGR pressure feedback sensor (DPFE)
  • EGR valve position sensor (EVP)
  • And EGR temperature sensor are all examples of sensors used in the exhaust gas recirculation system.

The Basics

When the combustion temperature exceeds 2500 degrees Fahrenheit, NOx emissions are produced. EGR systems are used to lower the temperature of the combustion process, hence lowering the generation of NOx. The exhaust gas recirculation (EGR) system recycles a tiny quantity of exhaust gas from the exhaust system (often little more than 10 percent) and mixes it with the intake manifold air entering the combustion chambers, which results in increased efficiency. This inert (or non-combustible) exhaust gas is introduced into the combustion process to keep the peak combustion temperatures below 2500° F, which is the temperature range at which nitrogen oxide (NOx) generation is known to occur.

Misfires will enable raw hydrocarbons (HC) to be expelled from the exhaust in these situations.

P0401 Diagnostic Theory for Shops and Technicians

A code P0401 indicates that the EGR flow monitoring conditions have not been satisfied, and the computer will display this message. The EGR monitoring criteria consist of a series of test values that are typically performed under at least two separate driving conditions: steady speed highway driving and steady speed city driving, respectively. There are several methods in which the engine control module calculates adequate EGR flow:

  • A code P0401 indicates that the EGR flow monitoring conditions have not been satisfied, as shown by the computer setting the code in question. The EGR monitoring criteria are a set of test values that are typically performed under at least two separate driving conditions: steady-speed highway driving and steady-speed city driving, respectively. Proper EGR flow is determined by the engine control module in a variety of ways.

The code P0401 indicates that there is an issue with the EGR valve, which is commonly the case. More accurately stated, the EGR system is not allowing sufficient EGR to flow back into the combustion process in order to adequately cool the peak firing temperatures. A scan tool should be used to extract the code P401. Once the code has been collected, the freeze frame data should be logged and evaluated in order to identify what engine conditions existed at the time the code was triggered.

A data streaming scan tool attached to the car should be operated in such a way that the code setting circumstances are replicated, so that the behavior of the EGR actuating components and feedback sensors can be observed and analyzed.

Common Tests to Determine Whether the Problem Is an EGR Control Problem, a Plugged or Restricted System, or a Defective Feedback Device

  • When the EGR valve is manually increased to its maximum setting, does the engine die rather than merely sputter? (If it’s a digital EGR valve, either a vacuum pump or a bi-directional scan tool should be used.)
  • Is there enough suction going through the EGR valve? (Use the EGR vacuum specifications provided by the manufacturer.) Is the EGR system restricted? (The engine stutters, but it does not shut down.) Is the exhaust gas recirculation system plugged? (The engine’s revolutions per minute remain constant.) Is the EGR valve operational? Increase the engine speed to 3000 RPM and check the manifold vacuum. Then turn the EGR valve all the way up to its highest setting—the manifold vacuum should drop by at least 3 inches of mercury. If it does not, there is an issue with the flow and/or limitation
  • With a propane torch and a DVOM, check the temperature of the EGR sensor (if it is provided). By raising and lowering the EGR valve, you may determine the accuracy of the EGR valve position sensor using a scan tool or a DVOM. Using a data streaming scan tool, check the Digital EGR Pressure Feedback Sensor (DPFE) to ensure that the voltage or lift % changes in accordance with specifications. When the EGR valve is opened, check to see whether the readings from the front Oxygen Sensor drop and the Short Term Fuel Trim increases. (The EGR removes the impurities from the mixture.)

Note

Generally, if the NOx decreases when the EGR valve is lifted (as is often done on a Dynamometer), this indicates that one or more EGR routes or cylinders are clogged or severely limited, resulting in the EGR only flowing to one or two cylinders or cylinders. When this occurs, you may observe misfires and even misfire codes in addition to the P0401, which indicates a problem. When a vehicle’s EGR ‘runners’ are used for each cylinder, this might happen to it.

FORD P1408 – OBD Codes

Generally, if the NOx decreases when the EGR valve is lifted (as is often done on a Dynamometer), this indicates that one or more EGR channels or cylinders are obstructed or severely limited, resulting in the EGR only being delivered to one or two cylinders. As a result of this, you may observe a number of misfires and even misfire codes in addition to the P0401. When EGR ‘runners’ are used for each cylinder in a car, this might happen.

Possible causes

  • Regarding vacuum-activated systems, see the section on Possible Causes of DTC P0401. For the electric motor system, see DTC P0400: Possible Causes for more information.

Diagnostic help

Use the output state control function of the scan tool to turn on the electric EGR while keeping an eye on the MAP PID (MAP) and the EEGR PID (EGRMDSD) readings. If EGR is fed into the engine when it is running at idle, the engine’s rpm will reduce and the engine will stall. See Diagnostic Aids for P0401 for information on vacuum systems.

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