Technical Ducato P0401 P0402 P0236 P0238 and limp mode its 2017 Euro 6, EGR changed, What do I check next

[Serrow225]

My lperg cooler was replaced beginning of last year and I've done around 4000miles ( was not used for 5 months over winter) and been reading thread each new post , I was waiting till I got a p401 again before deciding what to do next ,but am now thinking seeing recent data posts, are we doing more damage driving with a failed DPF ?
The soot recurulating in turbo , combustion chambers ?seem stupid we have a air filter in system,but it then pulls in contaminated gas back in combustion cycle due to faulty DPF.
I check tail pipe every drive and am still confused why I get sometimes very faint soot on paper wipe ,then next time it's thick black deposits? I can only think it's affected by regeneration process, with the crack in DPF opening up more after regeneration allowing more soot through?
Is it time to just bit the bullet ,

 

[Fredastaire]

@Serrow225 in first instance please can you do a CSV data run and send to @theoneandonly, he can quickly analyse the data and produce a histogram as above so we all can see the current LP cooler state at 4000 miles.
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Respect to your open question above, I'm not sure how much soot will reach the turbo, maybe the cooler mesh collects it first?
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I still think we need to stop the full travel of the LP EGR servo motor, then we could ignore the blocked cooler. An engine with a partially blocked cooler seems to survive a good few thousand miles until it reaches the point where it finally closes it's internal butterfly resulting in strangulation.

 

[Serrow225]

@Serrow225 in first instance please can you do a CSV data run and send to @theoneandonly, he can quickly analyse the data and produce a histogram as above so we all can see the current LP cooler state at 4000 miles.
.
Respect to your open question above, I'm not sure how much soot will reach the turbo, maybe the cooler mesh collects it first?
.
I still think we need to stop the full travel of the LP EGR servo motor, then we could ignore the blocked cooler. An engine with a partially blocked cooler seems to survive a good few thousand miles until it reaches the point where it finally closes it's internal butterfly resulting in strangulation.

Yep,I'll do a Data run next time we go in van , I must admit I've been reluctant to see what my vans data " head in the sand approach at moment" , and if it's not broken don't mess with it approach after last year at garage.
And I've been more careful about using van knowing it's milage limits now . massive respect to everyone on here who have tried to find a solution to our dilemma, it's just unfortunate we still have no magic fix hence why put up post .

 

[theoneandonly]

Yep,I'll do a Data run next time we go in van , I must admit I've been reluctant to see what my vans data " head in the sand approach at moment" , and if it's not broken don't mess with it approach after last year at garage.
And I've been more careful about using van knowing it's milage limits now . massive respect to everyone on here who have tried to find a solution to our dilemma, it's just unfortunate we still have no magic fix hence why put up post .

Until the magic fix is found for most people the answer has to be bite the bullet and replace the DPF a full job. As to collecting data, I try to monitor every journey over 3 miles. When BAz in kent had his first refurb he monitored evrey day for a few months then stopped for over 2 weeks (travelling every day) then a P0401. There it was -gone. the chance to see the transition from good to fail. So @Serrow225 please take the data it will help with predicability ie can i see trends that show cooler is blocking. I suspect it will be a short period just before its blocked.
As to your thought every second running with a cracked DPF is detrimental, possibly though i suspect the LPEGRcooler and filter is efficient at preventing harmfull size stuff entering turbo/combustion area. especialy when we see what happens in the HPegr loop. One thing is certain the longer you have run with a cracked DPF the more I would reccomend dismatling the entire induction system and clean inlet manifold hpegr and cooler intercooler throttle body, injectors.

 

[Serrow225]

Until the magic fix is found for most people the answer has to be bite the bullet and replace the DPF a full job. As to collecting data, I try to monitor every journey over 3 miles. When BAz in kent had his first refurb he monitored evrey day for a few months then stopped for over 2 weeks (travelling every day) then a P0401. There it was -gone. the chance to see the transition from good to fail. So @Serrow225 please take the data it will help with predicability ie can i see trends that show cooler is blocking. I suspect it will be a short period just before its blocked.
As to your thought every second running with a cracked DPF is detrimental, possibly though i suspect the LPEGRcooler and filter is efficient at preventing harmfull size stuff entering turbo/combustion area. especialy when we see what happens in the HPegr loop. One thing is certain the longer you have run with a cracked DPF the more I would reccomend dismatling the entire induction system and clean inlet manifold hpegr and cooler intercooler throttle body, injectors.

Thanks for your comments, I will do data when I use van and will start the process to get DPF replaced, as I will be keeping van so it's worth the investment.

 

[Fredastaire]

Mine from first cooler change did something like 15k miles. @theoneandonly noticed I had slight turbo lag, I had noticed high readings on the LP opening values. I never got the mil light, however looking MES had a stored code 0401. I decided as a had a brand new cooler to hand that I would have it changed to give me another two years.
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I am testing resistors across the LP EGR temp probe wires, watch this space..,.............

 

[Serrow225]

Mine from first cooler change did something like 15k miles. @theoneandonly noticed I had slight turbo lag, I had noticed high readings on the LP opening values. I never got the mil light, however looking MES had a stored code 0401. I decided as a had a brand new cooler to hand that I would have it changed to give me another two years.
.
I am testing resistors across the LP EGR temp probe wires, watch this space..,.............

I'm working out my options hence my gauging peoples opinions, we are possibly moving house in near future and if I'm going to spend a large amount of money on van , I'd better do it now before money is allocated to moving etc .
I been holding out so far for the magic fix but if I'm going to sort it out it's probably now or never !
Also our vans had a short production run , I guess the DPF is unique to this van .. how long are parts guaranteed to be available?

 

[Jiwawa]

Mine from first cooler change did something like 15k miles.

Mine was about 11,000 kilometres, so less than 9,000 miles.

 

[athoirs]

In November last year I replaced my LPEGR cooler and had the DPF professionally cleaned due to the usual suspect of P0401 codes and limp modes occurring. Since then I've only had some short runs in the Van with no warnings and the temperature is back up the 100+C and apart from out of spec injectors all looks fine on the computer (in my humble opinion). However, I am still seeing some soot on the exhaust tailpipe.
What brought things home to me was meeting up with a friend who has the same engine - a year older - and I had a look at his exhaust - as clean as new! not even a bit of soot.
I can only think with the way the DPF is designed- with basically its exhaust output split into two - one going to the silencer and the other going straight to the LPERG cooler - If there is ANY soot on the tip of your exhaust - your LPEGR cooler WILL soot up at some point.
I've managed to source an brand new DPF and will be fitting it when it gets warmer

 

[Paravan]

Posting my data as an additional data point. It seems in accordance with all the previous data and graphs posted here.

 

[theoneandonly]

Posting my data as an additional data point. It seems in accordance with all the previous data and graphs posted here.

Thanks not all pids measured as template 4 but appreciated .
Injectors either ive made a mistake on the multiplier or this is one the bestinjector results ive seen (are they new?)
The HPEGR As expected and working.

The LPEGR itemperature is low and indicative of a blocked cooler.
The openning values (graph 3) vary widely between min and max, this is also seen in the histogram of openning (ie either large or small opennings) These reflect a blocked cooler. This is a nice example of histogram showing open or closed.

 

[Paravan]

Thank you for confirming this. I think the scale of the injector graph is one order of magnitude off? So instead of 0.4 it should be 4. Or at least that's how the values are in the CSV file.

 

[Serrow225]

I feel like it's banging head against a brick wall sometimes.
So I'm trying to get prices for DPF and. Cooler from fiat professional,and service department was asking why I wanted to change it , I explained that DPF is cracked and soot is entering LP cooler etc etc , and was informed every diesel engine has black soot on exhaust and it's normal... They said probably best bring it in and let technicians plug in diagnostic to see if it's all ok .. what hope do we have when we have to tell them why I want it done !!! If only I could do it myself... And when I had cooler change last year nothing was wrong with it !
The mesh screen told a different story?

 

[Fredastaire]

I won't go in to detail but I have accessed the wiring to add resistors in parallel to the LP temp probe to see if I could get the software to stop full travel of its servo motor, thus stop strangulation. I've tried different ohm resistors. So far no success as it throws fault codes on engine start up. Whilst Im now not optimistic I'm still to try again with a different ohms.
I'm now mentally thinking of an earlier idea to modify the cam plate inside the LP EGR. However; this may need cutting an access panel in the passenger foot rest area, then making a cover panel.
The engine seems to cope with a nearly blocked cooler, it's just when the LP EGR goes full travel and closes the butterfly of the fresh air in....
So....still thinking.......

 

[Serrow225]

I won't go in to detail but I have accessed the wiring to add resistors in parallel to the LP temp probe to see if I could get the software to stop full travel of its servo motor, thus stop strangulation. I've tried different ohm resistors. So far no success as it throws fault codes on engine start up. Whilst Im now not optimistic I'm still to try again with a different ohms.
I'm now mentally thinking of an earlier idea to modify the cam plate inside the LP EGR. However; this may need cutting an access panel in the passenger foot rest area, then making a cover panel.
The engine seems to cope with a nearly blocked cooler, it's just when the LP EGR goes full travel and closes the butterfly of the fresh air in....
So....still thinking.......

And from your original start of the thread, it seems to happen only when engine warms up to temperature,I thought it must be the water vapour in exhaust makes the soot into a paste totally blocking LP cooler till it turns back to powder when hot ?

 

[CheeseMonster]

I won't go in to detail but I have accessed the wiring to add resistors in parallel to the LP temp probe to see if I could get the software to stop full travel of its servo motor, thus stop strangulation. I've tried different ohm resistors. So far no success as it throws fault codes on engine start up. Whilst Im now not optimistic I'm still to try again with a different ohms.
I'm now mentally thinking of an earlier idea to modify the cam plate inside the LP EGR. However; this may need cutting an access panel in the passenger foot rest area, then making a cover panel.
The engine seems to cope with a nearly blocked cooler, it's just when the LP EGR goes full travel and closes the butterfly of the fresh air in....
So....still thinking.......

Does the engine ECU just check LP temp probe for its presence and an expected value before start up?

If you added your resistor after engine start would it be happy then?

 

[deejays]

Does the engine ECU just check LP temp probe for its presence and an expected value before start up?

If you added your resistor after engine start would it be happy then?

@CheeseMonster @Fredastaire From my experience of adjusting sensor impedances, the ECU has obviously been programmed to sense when a sensor (within a group of sensors) goes outside the allowable design impedance envelope for existing conditions of the monitored group. This is intelligent design and unfortunately enforces a limit on how far you can alter the impedance of the sensor. So Fred, may I suggest you start testing for the boundaries of that envelope by starting off small and slowly adjusting the sensor impedance in small steps until you find the edge of that envelope (generated fault code). Then come back to the last known "working" value and see if that will serve the purpose you desire. I understand the conditions are continually monitored, and not just at start up. It may turn out that you have to "switch" in the selected resistor after the engine has reached operating temperature as it may be inside the expected operating impedance when at operating temperature, but not with a cold engine at start up. However, it is likely referenced against engine water temperature and other sensors as well so may not make any appreciable difference with success. I wish you luck with this Fred - your efforts are appreciated.

 

[Fredastaire]

@deejays how about joining in on the research with your van? I also invited any of our members. We need volunteers to work at and think 'outside the box'

 

[Serrow225]

I'm still trying out experimental attempts at clearing soot from cooler , I did rig up a mock up with old cooler and using a rubber hose inserted up pipe to see the effect of compressed air on clearing mesh screen. I'm hoping it may help get a few more miles out of system before blocking totally?

 

[theoneandonly]

I'm still trying out experimental attempts at clearing soot from cooler , I did rig up a mock up with old cooler and using a rubber hose inserted up pipe to see the effect of compressed air on clearing mesh screen. I'm hoping it may help get a few more miles out of system before blocking totally?

All attempts/ ideas welcomed. As alternatives propriety DPF cleaners squirted up may be safer than high pressure caustic (not reccomended). The resting position of the valves (cold) would be usefull to know to prevent soot / caustic / rinse water being blasted down the turbo.