This does not refer to earlier single EGR systems or to later AdBlu SCR engines.
Note this is a guide and not definative. It is up to you to make decissions. It is the result of my investigations of data from many contributors and discussion with many Fiat Forum members, its their work I’m just reporting it. As it would be totaly unfair to mention just one and not to acknowledge all contributors i wont mention FredAstaire.
for a more detailed description how-does-a-twin-egr-engine-work
What is a LPEGRcooler? Its a part of the emissions control system on the Ducato twin EGR no Adblu engines.
This engine can suffer a problem unique to itself that of a blocked LPEGRCooler.
How can we diagnose this problem and prevent it.
How does it appear.
How to diagnose.
What is Root cause.
How does it appear.
What is apparent problem How does it Raise its head.
Excessive soot is generated and has to go somewhere if there is a crack in DPF the soot will be shared between atmosphere and cooler. It may be evident by soot in the exhaust pipe (wipe with kitchen roll).
How to diagnose.
If the MIL is iluminated then error codes may be availble eg P0401,P0402,P0236, P0238. Typicaly a P0401 will exist with or without others in the group. It is pointles trying to solve other codes without taking on board the primary reason.
Why a P0401, Exhaust Gas Recirculation Flow Insufficient Detected. The 401 error always coincides with a large demand and inability to deliver it.
The inability to flow the desired Air volume is generally not due to the egr value being unable to do its normal function but the ecu asking for an implausible value. This is due to an ecu error or air flow not being possible due to another condition. Inside the LPEGR housing is a butterfly throttle that closes off the fresh clean air from the air filter in a controlled manner such that the turbo has to pull in an amount of sooty air from the cooler to blend the combustion air. With the cooler blocked the butterfly closes off any fresh air with the result that the engine is strangled. Because of the strangling effect the software tells the HP EGR to open in an effort to avoid this strangulation. The software gives daft unachievable opening instructions to this HP EGR which because it’s unable to do it throws the P0401 codes leading the unaware to change the HP EGR because the fault code says so!
The clogged cooler is not the root cause. Lets use the 5 whys
why do I get a P0401 et al?
Blocked cooler
why do I get a Blocked cooler?
excessive soot from DPF
why do I get excessive soot from DPF?
Cracked DPF
why do I get Cracked DPF?
Excessive temperature bad conditions durring regeneration
why do I get Excessive temperature durring regeneration?
Now we are getting closer to the root cause.
The clogged cooler is the reason for the P0401, but what is root cause.
What else do we know to drill further down into the cause
DPF gets cracked, but what causes it to crack?
Concider
1 the injection of fuel during regeneration is done using the standard injectors and not the world class method of a fifth injector. This gives the injectors a hard time and damage/ poor control more likely cleanliness issues and quality of jet control.
The function of the regeneration process is to increase the temperature above normal to facilitate the burning/conversion of soot to ash. If overfuelled we could have much higher temperature leading to cracking or melting.
2 Is it poor dpf design ? Or is it poor quality dpf inner filter component ?
poor Design an interesting question, Has the part number changed since 2016 no, so design probably deemed ok, however the dpf fitted to the twin egr model was of a new concept. These engines were the first to use production variant of what is now standard manufacturing technique. Now Because of my work in materials and process development I am well aware that problems can occur in early production phases of complex ceramic processess. So were early DPFs dodgy? or more suseptible to poor temperature control?
3 Software control. The ecu software version started at 13 but by 2018 was at least 24 my van was updated to 28 in March 2019 (the latest position as I understand it is Manual V28 Comformatic V32.
Poor regen algorithm, other overfuelling issues, better callibration data with experiance of engine hours running .
4 Other Factors. It is known that number of vans came from Sevel with the wrong MAP fitted (supply issues early on) this could lead to incorrect calibration and temperature issues. In first years there were also a number of Differential DPF sensors failed and 2 versions fitted, this sensor is important in the regen process, was it important in the failure process?
5 Forced Regeneration. If The DPF is blocked beyond a threshold value (unknown for this engine) it is probabable that the DPF will crack due to excessive temperature during a forced regen , it is for this reason that if regens occur less than 200miles apart regularly the DPF be cleaned or the Differential pressure DPF sensor be tested. Avoid forced regens without a cleanish DPF.
Question: Was there ever another root cause than clogged LPEGR Cooler reported for P0401/P0402/P0238 ?
The definition/ reporting of a blocked cooler does not come from a collection of Fault codes but from the analysis of live data, historical data and physical observation, however, given the selection of codes the live data eventualy points to the blocked cooler. The data from the freeze frame data of the P0401 gives a Actual Air Intake % of Desired of about 25% although a good engine will show variation nowhere as low as 30%. A problem engine will have LPEGR value data varying widely between open and closed and lower temperatures than a good engine. There will be excessive soot in the exhaust system.
Question: Why doesn’t a cracked dpf throw up a fault code?
There are No directly attributable sensors. ie all sensors still giving values within acceptable limits. The only sensors applicable in the area are the dpf differential pressure sensor and the 3 temperature sensors. The dpf pressure sensor with a cracked DPF will give values within spec The 2 oxygen sensors may give strange values under certain circumstances but be within specifications. The only error codes that indicate a cracked DPF are combinations of P0401 and P0236/ P0238
Question: I have a black exhaust is it cracked?
If it gets black than there is a problem with the air/ fuel ratio or a broken dpf.
Either to much fuel (check injector values) or to little air.
Or blocked / broken dpf (check dpf values, differential pressure, avg. regeneration temp., avg. regeneration km,...)
So should i avoid a duel egr no ,mine runs perfectly. there are still time bombs out there eg low mileage Motorhomes or any van that has never seen a Fiat pro service and has early version software, there is also a second stage where a few have failed at 180,000miles but also many that have achieved 250-300,000 miles. Check Fiatforum .com and search for P0401 plenty of advice. Get to it early and there wont be a problem. All mostly guesswork of course (or analysis of data).
I have no connection to Fiat or have had discussion with Fiat employees. I have been a Manufacturing, Production, Process Engineer within the Aerospace Industry for a while.
For further info and
Question : How do i monitor a good engine or prevent it getting worse.
Answer : Read the next installment
One other thing to concider Is regular use of injector cleaner (eg Liqui Moly Diesel) and the use of fuel additives (eg Millars ECO) and/or fancy fuel.
Ensure engine ECU is V28 for a manual (as a minimum) or V32 for a Comfortmatic. If problems are encountered with a manual it could be at V32.
Note this is a guide and not definative. It is up to you to make decissions. It is the result of my investigations of data from many contributors and discussion with many Fiat Forum members, its their work I’m just reporting it. As it would be totaly unfair to mention just one and not to acknowledge all contributors i wont mention FredAstaire.
for a more detailed description how-does-a-twin-egr-engine-work
How does a twin egr engine work
The following is a description of a twin egr engine edited from https://mechcontent.com/ and other sources It is not a detailed examination of the Fiat engine, if theres anything obviously wrong please advise. The internal combustion engine uses...
www.fiatforum.com
This engine can suffer a problem unique to itself that of a blocked LPEGRCooler.
How can we diagnose this problem and prevent it.
How does it appear.
How to diagnose.
What is Root cause.
How does it appear.
What is apparent problem How does it Raise its head.
Excessive soot is generated and has to go somewhere if there is a crack in DPF the soot will be shared between atmosphere and cooler. It may be evident by soot in the exhaust pipe (wipe with kitchen roll).
How to diagnose.
If the MIL is iluminated then error codes may be availble eg P0401,P0402,P0236, P0238. Typicaly a P0401 will exist with or without others in the group. It is pointles trying to solve other codes without taking on board the primary reason.
Why a P0401, Exhaust Gas Recirculation Flow Insufficient Detected. The 401 error always coincides with a large demand and inability to deliver it.
The inability to flow the desired Air volume is generally not due to the egr value being unable to do its normal function but the ecu asking for an implausible value. This is due to an ecu error or air flow not being possible due to another condition. Inside the LPEGR housing is a butterfly throttle that closes off the fresh clean air from the air filter in a controlled manner such that the turbo has to pull in an amount of sooty air from the cooler to blend the combustion air. With the cooler blocked the butterfly closes off any fresh air with the result that the engine is strangled. Because of the strangling effect the software tells the HP EGR to open in an effort to avoid this strangulation. The software gives daft unachievable opening instructions to this HP EGR which because it’s unable to do it throws the P0401 codes leading the unaware to change the HP EGR because the fault code says so!
The clogged cooler is not the root cause. Lets use the 5 whys
why do I get a P0401 et al?
Blocked cooler
why do I get a Blocked cooler?
excessive soot from DPF
why do I get excessive soot from DPF?
Cracked DPF
why do I get Cracked DPF?
Excessive temperature bad conditions durring regeneration
why do I get Excessive temperature durring regeneration?
Now we are getting closer to the root cause.
The clogged cooler is the reason for the P0401, but what is root cause.
What else do we know to drill further down into the cause
DPF gets cracked, but what causes it to crack?
Concider
1 the injection of fuel during regeneration is done using the standard injectors and not the world class method of a fifth injector. This gives the injectors a hard time and damage/ poor control more likely cleanliness issues and quality of jet control.
The function of the regeneration process is to increase the temperature above normal to facilitate the burning/conversion of soot to ash. If overfuelled we could have much higher temperature leading to cracking or melting.
2 Is it poor dpf design ? Or is it poor quality dpf inner filter component ?
poor Design an interesting question, Has the part number changed since 2016 no, so design probably deemed ok, however the dpf fitted to the twin egr model was of a new concept. These engines were the first to use production variant of what is now standard manufacturing technique. Now Because of my work in materials and process development I am well aware that problems can occur in early production phases of complex ceramic processess. So were early DPFs dodgy? or more suseptible to poor temperature control?
3 Software control. The ecu software version started at 13 but by 2018 was at least 24 my van was updated to 28 in March 2019 (the latest position as I understand it is Manual V28 Comformatic V32.
Poor regen algorithm, other overfuelling issues, better callibration data with experiance of engine hours running .
4 Other Factors. It is known that number of vans came from Sevel with the wrong MAP fitted (supply issues early on) this could lead to incorrect calibration and temperature issues. In first years there were also a number of Differential DPF sensors failed and 2 versions fitted, this sensor is important in the regen process, was it important in the failure process?
5 Forced Regeneration. If The DPF is blocked beyond a threshold value (unknown for this engine) it is probabable that the DPF will crack due to excessive temperature during a forced regen , it is for this reason that if regens occur less than 200miles apart regularly the DPF be cleaned or the Differential pressure DPF sensor be tested. Avoid forced regens without a cleanish DPF.
Question: Was there ever another root cause than clogged LPEGR Cooler reported for P0401/P0402/P0238 ?
The definition/ reporting of a blocked cooler does not come from a collection of Fault codes but from the analysis of live data, historical data and physical observation, however, given the selection of codes the live data eventualy points to the blocked cooler. The data from the freeze frame data of the P0401 gives a Actual Air Intake % of Desired of about 25% although a good engine will show variation nowhere as low as 30%. A problem engine will have LPEGR value data varying widely between open and closed and lower temperatures than a good engine. There will be excessive soot in the exhaust system.
Question: Why doesn’t a cracked dpf throw up a fault code?
There are No directly attributable sensors. ie all sensors still giving values within acceptable limits. The only sensors applicable in the area are the dpf differential pressure sensor and the 3 temperature sensors. The dpf pressure sensor with a cracked DPF will give values within spec The 2 oxygen sensors may give strange values under certain circumstances but be within specifications. The only error codes that indicate a cracked DPF are combinations of P0401 and P0236/ P0238
Question: I have a black exhaust is it cracked?
If it gets black than there is a problem with the air/ fuel ratio or a broken dpf.
Either to much fuel (check injector values) or to little air.
Or blocked / broken dpf (check dpf values, differential pressure, avg. regeneration temp., avg. regeneration km,...)
So should i avoid a duel egr no ,mine runs perfectly. there are still time bombs out there eg low mileage Motorhomes or any van that has never seen a Fiat pro service and has early version software, there is also a second stage where a few have failed at 180,000miles but also many that have achieved 250-300,000 miles. Check Fiatforum .com and search for P0401 plenty of advice. Get to it early and there wont be a problem. All mostly guesswork of course (or analysis of data).
I have no connection to Fiat or have had discussion with Fiat employees. I have been a Manufacturing, Production, Process Engineer within the Aerospace Industry for a while.
For further info and
Question : How do i monitor a good engine or prevent it getting worse.
Answer : Read the next installment
Ducato twin EGR Engine with P0401 Code (2016 to 2019)
This does not refer to earlier single EGR systems or to later AdBlu SCR engines. Note this is a guide and not definative. It is up to you to make decissions. It is the result of my investigations of data from many contributors and discussion with...
www.fiatforum.com
One other thing to concider Is regular use of injector cleaner (eg Liqui Moly Diesel) and the use of fuel additives (eg Millars ECO) and/or fancy fuel.
Ensure engine ECU is V28 for a manual (as a minimum) or V32 for a Comfortmatic. If problems are encountered with a manual it could be at V32.