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

[Fredastaire]

I got back the motorhome today. The results so far are. At FIAT they took off the DPF and it is dirty on both sides, so DPF is not doing the job. Also the exhaust pipe is not clean (i did not notice that before). It is a pitty that they did not check it with camera to see what is inside. they checked the intercooler at the entry from turbine and the pipes and intercooler are dirty as well. They checked the throttle body and MAP and both are clean. They replaced MAP with the new one.

Verdict was to replace.

LPEGR
HPEGR
DPF
INTERCOOLER

When i came home i took off the intercooler and exit side was clean as well as the pipe going from it to the throttle body. I cleaned the intercooler and it is clean now as new. There is a huge possibility that the DPF is cracked.

In my humble innocence that looks an odd concoction of parts. Whilst the 0401 code says HP EGR as you read the script, I don't believe it. Have you got the part numbers for the list of parts above? Where you have written intercooler I suspect it should read LP cooler which is the logical part to change with the suspension detached and subframe removed. Have they checked the injectors balancing? I would want to know what's caused the dpf to fail I might suggest that buying Multiecuscan would be a good idea so you can check things yourself.
The hugh problem we have is that so far nobody knows the real truth and there's a lot of guesswork by garage mechanics changing components and keeping fingers crossed. I only know what I know of my van from how far I've got. What are your plans for the next step?

 

[BobSlo]

I forgot, yes they checked injectors and they are fine. They did not know in what condition the EGR cooler is, but since it is the first part after DPF it has to be clogged somehow. They did not remove the sub frame, just detached the intercooler tubes. Yes it is a good idea to buy multiecuscan. Can you please help me with the brand and model of the interface.

I have to remove the DPF to check it with the camera. If it is cracked (and probably is) i have to buy new one. Then i have to clean the EGR cooler and replace the HPEGR, I am not sure if i should also check the turbine at specialist turbine workshop)?

 

[BobSlo]

Sorry, i meant to replace LPEGR not HPEGR

 

[Fredastaire]

@BobSlo the MES I bought was a package deal from Gendan Swansea, it includes the software, the license, the main adaptor cable and a yellow adaptor. The package costs UK 99.95 inc vat and is

FESCAN

MultiECUScan Package (CAN cars only)

 

[Fredastaire]

@BobSlo please send me a personal message with your email address. I'll send you screenprints of what I record now each longer journey. I strongly recommend you await to receive your MES and do some testing. from my personal efforts I dont see the need to replace the HP EGR, you can first look with MES and see it operating so you will know if its opening and closing. If you remove it then take off the servo motor you can operate the valve with your thumb to see if its sticking, then clean it with dilute Caustic Soda, takes minutes, I was flabbergasted at how quick it was to clean. Then you can look at the DPF readings and see how blocked up it is, there is a crazy figure of 100% which is sort of full yet MES says even greater % is still fine. My other european contact guy has been working on a clients Ducato to do a forced regen from 380% down to 40% at which point theyve handed it back to the customer, (No I havnt misstyped 380%). With MES you can see how many self regens its done since new, see how many KM it averages between regens to give you an idea of when the next regen is. I know that my DPF is self cleaning according to plan so I know I havnt a DPF problem. I still think that my cooler is probably blocked which is causing my 'soft code 0401' to be in memory, I'm hoping that somebody will come up with a method of getting at the cooler without removing all the subframe and steering rack. Maybe you can unbolt the engine and lift it up and forwards a bit and remove that DPF?
With MES you can do a drive and get your passenger to monitor airflows and pressures, for my Ducato I can see that the actual figures follow the requested figures so in normal driving I know that there is not much wrong, (I hope ).
Equally it would be good if somebody could do a remap and delete the LP EGR, I wouldnt delete the HP EGR though as I do have some responsibility for the environment. The Fiat twin egr system is just too complex.

 

[theoneandonly]

@BobSlo

Multiecuscan - Diagnostics software for Italian cars

Note there is one in Slovenia

 

[BobSlo]

I already called them twice but they did not answer the phone. I will try again tomorow morning. I found out that Gendan does not ship to Slovenia.

Today I spoke with a DPF specialist and he said that in case exhaust pipe is dirty it is almost 100% that the DPF is cracked. They can open the casing and insert new core. The cost is 680 EUR, which is reasonable in comparison to FIAT 2800 for the new one.

Is your exhaust pipe clean or dirty and black?

 

[BobSlo]

I got the seller in Slovenia, they stop selling MES, they had a bundle with ELM interface and had some hardware problems so decided to avoid troubles with customers. Stuck again.

 

[RS3100]

I got the seller in Slovenia, they stop selling MES, they had a bundle with ELM interface and had some hardware problems so decided to avoid troubles with customers. Stuck again.

I bought MES + the CanTieCar VCI direct from the author of the software. Before Brexit, it was substantially cheaper than buying it from Gendan or any of the other distributors. You can purchase from him direct on the MES site and he ships to all EU countries. There is also a list of authorised distributors on the site.
Alternatively, you can just buy the licence direct from him, and there is a list of approved (tested with MES) VCI interfaces in the help section of the MES site, which you should be able to find from various vehicle diagnostics suppliers, Amazon or eBay etc.

 

[theoneandonly]

I purchased the MAP sensor 0281002845

Incorrect part number was delivered, 0281006076​

the supplier says it has been superceeded by the provided part. should i accept it?

 

[Anthony489]

Hi theoneandonly

It's not unusual for parts to be superseded by the likes of Bosch. Checking on a couple of different major suppliers websites suggest that this part is compatible with the Ducato X250 and X290. I'd be inclined to accept it and use it.

 

[theoneandonly]

@Anthony489
thanks for that, the one i checked (ebay) said the 76 was not compatible with my particular model.

 

[theoneandonly]

eventually found the english version whilst looking for the following schematic

 

[Fredastaire]

The exploded parts view is NOT euro 6 (no adblue) which is the subject of this post, I've seen a proper picture at the dealers screen. The annotated functional diagram is correct however not quite clear enough. The LP EGR is a dual function device. It has the EGR 'inlet valve' AND has a butterfly. I think that both are operated together such that the turbo takes air from the air filter OR the LP exhaust. With the cooler blocked this will mean that the throttle will strangle the engine. This is illustrated on the MES recorded event when I get P0401. I think I now know what's happening. I would ask if any body can clarify my thinking

 

[Fredastaire]

The system diagram is also incorrect at top right. There is a butterfly throttle at the end of the intercooler pipe BEFORE it meets up a T junction / mixing chamber at the inlet manifold. The HP EGR feeds in to the T junction from the opposite side so is not controlled for flow other than by how much it's 'inlet valve' has opened.
This other throttle can only control the intercooler input flow. I've had it suggested that it's used on engine shutdown.
.
Overall I wonder about having the LP cooler changed AND have it's inlet from a fresh pipe to another air filter , (and blank off the t connection between dpf / exhaust pipe) such that the software can only bring clean air to the turbo.
.
OR buy another LP EGR, fasten it in fresh air under the bonnet, connect the electrics so the ecu still thinks it's doing something yet it's not piped in to anything. This would leave the original butterfly inactive so it can't throttle the engine.

 

[theoneandonly]

The first diagrams are from Fiat sales literature for the Euro6 twin EGR version so not necessisarily the real truth.
The second is from Coastal Motorhomes and for the LP EGR valve for a 2017 engine. The page also states there are 2 options of the LP EGR valve. Have you any alternative correct literature.

 

[Fredastaire]

The first diagrams are from Fiat sales literature for the Euro6 twin EGR version so not necessisarily the real truth.
The second is from Coastal Motorhomes and for the LP EGR valve for a 2017 engine. The page also states there are 2 options of the LP EGR valve. Have you any alternative correct literature.

This is my take on the Euro 6 non adlue system

 

[kangexpress]

Hello,

my first post in that forum.

Having the same issues with P0401, P0402, P0238.

Following parts have been changed by FIAT Dealer.

HP EGR (twice)
LP EGR
LP EGR Cooler
DPF
TURBO

The HP EGR was changed twice.

The Code P0401 means that the actuator of the HP EGR Valve isn't working correctly. Stuck open or stuck close. Or isn't moving.

But live data isn't showing any abnormalities.

Both HP EGR and LP EGR are working fine.

Sometimes the desired boost pressure is lower than the actual boost pressure.
Than the code P0238 is saved in ECU.

The other both codes P0401 and P0402 are most of the time hidden and doesn't throw the limp mode or check engine light in.
But sometimes they do. (rarely)

Thats why I've red this thread and cleaned the throttle body valve, the MAP sensor and the MAF.
Also changed the Air filter.
There was everywhere a thin sticky and oily film / layer in the insed of the parts.
Also checked the pipe from turbo to cooler.
Also thin layer of sticky oil inside.
Cleaned everything properly and build back together everything.
Also reseted the ECU data for sensor and actuator calibration via MES.

But still engine is shaking/vibrating a little bit.
Maybe normally someone wouldn't even notice the slight shaking.
But I've driven this van 611.000 km. So I can tell even sligltly differences in engine noise or vibration.

Engine idle is rougher than normally.

All these actions didn't help.

Still throwing the same codes.

So I decided to record the parameters with MES.

That's what I've found yet:

If I'm doing a cold start (turn of engine for 2-3 minutes) and only turn the key on ignition and don't start the engine than MES shows desired air quantity of 3200 mm3/i.
That's an impossible value to reach for this engine.
In normal condition you will have 300-400 mm3/i in idle.
And max. 2000 mm3/i in full load.
You will never reach 3200 mm3/i.
If I do warm start (no sleeping time for ECU, turn of engine and immediately turn on ignition) than the disred air quantity has a normal value (300-600 mm3/i).
But in cold start case, if turned on ignition and ECU is showing desired air quantity of 3200 mm3/I and than start engine and press immediately accelerator, than the P0401 code will be saved in ECU.
In data freeze frame for that code you will than still see the desired air quantity of 3200 and the actual air quantity of 400-800 mm3/i.
Mostly with 1600-2100 rpm.
If the code is saved, doesn't mean that MES will show it to you immediately.
But if you drive now some time and then park the van and turn of the engine you will see in the data records that ECU is still active.
You will see that ECU tries to move EGR three times.
And all three times EGR actual position goes up to 5mm.
But while the ignition and engine is off, the desired EGR position is showing zero 0 mm.
That makes no sense.
And than the first code is also showed by MES.
Because the failure was already there.
And ECU tried to recheck after engine off.
But wasn't successful in checking.
So the code goes to active.
And is shown in MES OBD scan.

I'm thinking that this is a programing issue in the ECU Software.
My Version is also 0032.

3200 mm3/i air quantity just does not make any sense at all.
ECU isn't changing desired values fast enough.
Actual Values from sensors are faster.
So the code is saved.

And also it makes no sense that after turning of the engine the EGR Valve is moved three times by the ECU to recheck if the problem is current.
But doesn't show any desired value for opening EGR Valve.
The test routine in software for EGR is faulty.

Attached some pictures.

I've already invested 7500,-€

What to do next???

 

[BobSlo]

I also found the same thing with the desired air quantity beeing abnormally high. Yesterday i connected MES to healthy Ducato euro 5 and values of the desired and measured air quantity were always close by, measured was folowing desired.

What is strange to me is what caused the DPF to fail. Exhaust on my motorhome is not clean it has soot and that means DPF is not doing what it is suposed to do, because soot should not pass the DPF.

 

[Fredastaire]

@kangexpress , welcome to the P0401 club, you are far from being alone.
I'm just to give the briefest reply at the moment, I will re-read and add more comments later.
.
I am of the opinion that there are at least three possible non linked faults
1/. This mysterious air flow calculation problem - reason unknown.
2/. At least three off us have MAP sensors of an apparently incorrect part number factory fitted.
3/. Turbo solenoid vacuum switches fail at circa 25,000 miles becoming lethargic in operation which will slow the turbo response and affect manifold pressures.
.
Since early December 2021 when I changed my MAP and Solenoid, I have lost my other fault codes and now only see P0401
.
I agree with seeing the same snapshot freeze frame error for P0401 of actual airflow being 1/4 of requested.
.
You only refer to one throttle, there are two, one integral inside the LP EGR.
.
The P0401 code definition of 'HP egr blocked' is to my opinion wrongly leading us in to replacing HP EGRs. It should read 'LP EGR blocked'
.
My current thought question is how to disable the LP EGR throttle as I think with a blocked cooler that this throttle is strangling the turbo input air. I wish I could do something to test my theory.
.
Im engaged with something else just now, Ill think during the day and add more notes ...
.
Last comment, my van ran perfectly ok for its first 23,000 miles, something must be worn out or filled with soot. (do silencers get blocked?)