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

[deejays]

@jansla I am very much thinking there may be two issues at play here. One is a blocking cooler, and the other is there is something amiss with the Turbo Actuator Command. So, perhaps both the chicken and the egg are in play. And speaking earlier of reverse engineering, I suspect we (at least I) have got the direction of the Turbo Actuator Command in reverse. What I mean by that, is that at start up, and very low load demands (idling engine for example) the value is always high - near 100%. So I think it is reverse logic that applies to this signal, and that is a high number means very little to no influence on the boost mechanism, and the lower the number goes then there is more control exerted over the boost function. What also reinforced our original thinking was that when the fault flags, and the vehicle enters limp mode, that number falls to 0. But I think in this situation, it means nothing other than all boost is off - including any sort of EGR as all values fall to 0. The engine is then operating as a non-turbo diesel with no EGR and probably plenty of other restrictions.
This thinking has led me to carry out another test run on my vehicle with the revised template (applicable to the 150/180 engine) and the response of that signal on my vehicle confirms that suspicion. I will post the details later as I have other fish to fry right now (literally - it's dinner time!). What would be of the absolute benefit for you would be for some kind soul who has a faultless 130HP engine to run the revised template and post the CSV file for you.
I will post mine and some screen shots after dinner - you might be surprised by what you see.

 

[jansla]

@jansla , I think you have uploaded older files that you have previously uploaded and not the new template ones as intended.

asch! You are right! It was a very busy day for me yesterday and I made mistake, sorry for that, Here comes correct ones from yesterday, first with fault and limp mode second sfter resetti g

 

[deejays]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:

Cold start to 750 seconds:

975 to 1263:

975 to 1263:

 

[jansla]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:
View attachment 467248

Cold start to 750 seconds:
View attachment 467249

975 to 1263:
View attachment 467250

975 to 1263:
View attachment 467251

@deejays Yes! I agree. It makes sense! Absolutely. This way all parameters are connected and behave as expected. No doubt that in my case turbo will not or can not deliver what it is asked for (this is the most obvious now) and the temperatures show unexpected values. Difficult to go any further with analysis and the next step should be to look closely at turbo and LPEGR cooler, and as we well know this can not be done by DIY-er by himself (myself). Wednesday next week (appointment in the garage) is going to be the beginning of a new chapter - hopefully.

 

[deejays]

@deejays Yes! I agree. It makes sense! Absolutely. This way all parameters are connected and behave as expected. No doubt that in my case turbo will not or can not deliver what it is asked for (this is the most obvious now) and the temperatures show unexpected values. Difficult to go any further with analysis and the next step should be to look closely at turbo and LPEGR cooler, and as we well know this can not be done by DIY-er by himself (myself). Wednesday next week (appointment in the garage) is going to be the beginning of a new chapter - hopefully.

Have you tried running the Actuator Test in MES for the Boost control solenoid and at the same time observe the linkage from the actuator to the turbo to see if it actually moves?

 

[Fredastaire]

@jansla I would suggest that you can DIY inspect the cooler yourself. With the van up on ramps you can lie down and wriggle underneath. There is a stainless flexible pipe from the DPF outlet to the LP EGR inlet pipe. The Flexi has a special clamp with a single clamp screw (13mm af head). You can easily undo the clamp screw and remove it. Then refit with two M8 standard nuts in the middle. Screwing the nuts opposite ways expands the clamp to open it up and release the Flexi
You could then slide an endiscope upwards to inspect.
I've had an endiscope up my removed/ cleaned cooler, I've undone the clamp on my Ducato, just not done the above endoscopy on my van itself.

 

[Fredastaire]

I've done another trial on the LP EGR temp sensor. We don't know what it's there for. I was wondering if it was used to control the LP EGR opening either graduated or as a high temp policeman to prevent high temp exhaust reaching the turbo. I've added different resistance values in parallel with the sensor wires to send a wrong high temperature to the ECU. I've got as far as a false temperature of 160 degrees but the EGR is still modulating. I've yet to do a road run with CSV recording before I finally give up. At best I will have answered a question.
.
We still need a way of shutting the LP EGR off without a software delete.
.
I've still in mind the mod by Cariou.....

 

[jansla]

@jansla I would suggest that you can DIY inspect the cooler yourself. With the van up on ramps you can lie down and wriggle underneath. There is a stainless flexible pipe from the DPF outlet to the LP EGR inlet pipe. The Flexi has a special clamp with a single clamp screw (13mm af head). You can easily undo the clamp screw and remove it. Then refit with two M8 standard nuts in the middle. Screwing the nuts opposite ways expands the clamp to open it up and release the Flexi
You could then slide an endiscope upwards to inspect.
I've had an endiscope up my removed/ cleaned cooler, I've undone the clamp on my Ducato, just not done the above endoscopy on my van itself.

I’ve opened that flexi for inspection before the summer last year. I have had borrowed inspection camera so I could have a look att the bottom of the DPF (was quite ok, not that sooty as the exhaust pipe outlet) but I couldn’t reach any further

 

[jansla]

@jansla The following is for my 150HP, one would hope it gives an indication of what should be expected of the 130HP. The Turbo Actuator Command starts out at the same place, but for the healthy engine is modulating around the 50% mark (which does make a lot of sense). The Actual Boost tracks very closely the desired Boost. The LPEGR Temperature rises quickly, and the Inlet Manifold Temperature is modulating around the 55C mark. There is minimal HPEGR input, and the LPEGR valve is modulating around mid-travel, never full open, and not flat-lining.

Overview:
View attachment 467248

Cold start to 750 seconds:
View attachment 467249

975 to 1263:
View attachment 467250

975 to 1263:
View attachment 467251

@deejays I was thinking about how to compare our engines which although not exactly the same differ only by 20HP from the factory and considering my tuning maybe not even that much. I compared what was recorded in your csv file from 2505191149 with mine after removing errors 2505181724. Lots of similarities. But not all parameters are the same. I tried to compare different speed ranges but in the end I chose to compare the records that each of us obtained by setting the condition that the gas pedal was pressed 40% or more. Then usually the engine works under some load, overcomes the resistance or accelerates. It did not look like there were any extreme conditions but just normal driving. Smaller loads can give differences resulting from how hard you accelerate, but above 40% gas pedal it can be assumed gives similar conditions.

So I filtered those rows from csv files where the pressure on the accelerator was 40% or more. For each recorded parameter after filtering I calculated the average values and compared them. Most looked similar. There were clear differences in the difference between the desired and current boost pressure. In my file there was an underboost of 180mbar on average and in yours no significant difference. The average boost value in your case was greater by about 300mbar copared to mine. HPEGR was rather closed in both cases, LPEGR in your 1.6 in my 4.3, i.e. mine tended to be constantly open.

In my opinion, the results regarding the amount of air flowing through the MAF sensor are interesting. If I'm not mistaken, the MAF is located between the air filter and the LPEGR valve, which means it only reads what reaches the turbo through the air filter.
Before entering the turbo, this clean air mixes with the dirt gases that the LPEGR valve makes available. There is a butterfly valve there that supposedly cuts off the air from the air filter. But does it completely? If the gases from the LPEGR cooler were blocked due to the LPEGR cooler being clogged, nothing would pass through when the LPEGR valve was opened. And the butterfly valve would cut off the air from the air filter. The engine should choke and stop. However, this is not happening in my case. Look at the MAF sensor reading. It goes about the same as in your engine.
And this is what puzzles me and raises doubts as to whether the LPEGR is really clogged. If air cannot get through the LPEGR because it is clogged and opening the LPEGR valve is supposed to close access to air from the filter, where does this air come from? The system is tight, which was checked. So is the LPEGR really clogged? This results from observing temperatures. However, compressed air has a higher temperature than the same air at lower pressure. Well, I don't know how much higher, but probably higher. Your turbo has a greater compression effect than mine. This may give a higher temperature. If the LPEGR does not let through as much gas as it should, more should be taken from the filter.
A comparison of your and my parameters shows that these are similar amounts of air taken to manifold, measured by MAF and even a little more in your case, and it should be the other way around if LPEGR was clogged.
While the difference in our parameters clearly indicates that my boost is too low, I don't know if it is just as obvious an indication of LPEGR cooler obstruction, although it is quite possible. Why is lambda oxygen after DPF twice as large in your case compared with mine? What do you think about these differences?

 

[deejays]

I've done another trial on the LP EGR temp sensor. We don't know what it's there for. I was wondering if it was used to control the LP EGR opening either graduated or as a high temp policeman to prevent high temp exhaust reaching the turbo. I've added different resistance values in parallel with the sensor wires to send a wrong high temperature to the ECU. I've got as far as a false temperature of 160 degrees but the EGR is still modulating. I've yet to do a road run with CSV recording before I finally give up. At best I will have answered a question.
.
We still need a way of shutting the LP EGR off without a software delete.
.
I've still in mind the mod by Cariou.....

Reverse engineering is a challenge! From observation, the LPEGR valve is barred from opening until an external temp sensor gets to a certain point. That sensor may be the Temperature after the particle filter sensor as it is the temperature of the gases entering the cooler. Then there may be a number of sensors driving the actual opening amount of the LPEGR valve. The main suspects would be the O2 and exhaust gas temperatures. EGR attempts to reduce the combustion O2 levels and temperatures. I suspect the LPEGR temp sensor to be a max temp limit to shut the valve (policeman) to protect the rest of the system and also would form part of the fast regulatory circuit. The LPEGR has been observed to operate during a DPF regen with elevated exhaust temps, and I suspect the temp limit for the policeman is lowered during the regen as the rate of LPEGR temp increase is so rapid. The LPEGR valve only spikes open briefly during the regen.

 

[deejays]

I’ve opened that flexi for inspection before the summer last year. I have had borrowed inspection camera so I could have a look att the bottom of the DPF (was quite ok, not that sooty as the exhaust pipe outlet) but I couldn’t reach any further

The pipe you need to insert the borescope into is the one leading to the cooler, not the DPF to exhaust pipe junction. The photo below showing the "aftermarket" wire mesh. The pipe you need to insert the borescope into is the one covered by the wire mesh.