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

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

Fredastaire

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Dec 19, 2017
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Van is 2017 Euro 6 bought new , now with 26K on clock.

Problems started this summer with dash engine light and code P0401 appeared on a country lane at low speed going into a corner so it would be low airflow going in to the engine as it wasn’t ‘working’. Bought FCR and cleared fault, happened again days later, including P0402, cleared it.

So its an intermittent fault., it might be days before it happens again. Dealer had a look, diagnosed software needed latest issue which he installed.

Still getting P0401

Then going up a hill with foot down a bit I get a double whammy of P0401 and P0236 plus P0238 and the dreaded limp mode.

After much reading on here I decided to but MES software for laptop and checked things, both EGR’s cycle fine, DPF is cycling fine and not blocked so scratching head and thinking, more reading on here and I decided to change the top high temp EGR thinking it was sticking. Brand new Fiat part from Coastal Motorhomes fitted and codes cleared, still intermittent getting P0238 P0236 and Limp Mode.

More reading on here led me to check the fine bore plastic vacuum / pressure pipes, all fine, more reading so took the left hand intercooler pipe assembly off suspecting cracked bracket, perfect, looked inside cooler, not blocked, visually checked the RH intercooler pipe – fine, checked intercooler – fine.

Ive ordered new Fiat MAP and turbo vacuum solenoid, yet to arrive.

I would appreciate comments and advice as to what I do next, Ive been told @whineO or @Euroserve might be able to advise, is it possible?
 

Anthony489

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Hi Fredastaire

The meaning of these codes in a Ducato context (as far as I can tell) is as follows:

P0401 Exhaust gas recirculation flow insufficient

P0402 Exhaust gas recirculation flow excessive

P0236 Turbo boost sensor range/performance. (Measured pressure greater than commanded)

P0238 Turbo boost sensor input circuit out of specification (High boost reading when no boost demanded)

I suspect that the monitoring of EGR system performance is done partly indirecly, i.e. it includes readings of manifold pressure / boost derived from the Manifold Absolute Pressure (MAP) sensor. So a fault in the MAP or its wiring could result in an EGR system error being flagged even with no fault in the EGR components.

The P0236 and P0238 codes suggest a fault with boost pressure or its measurement, and the "limp home" mode is a precaution in case there really is excess boost pressure. Replacing the MAP sensor and checking its wiring and connector (as you plan) would be the logical next step. These sensors have a tiny hole between the manifold end and the internal semiconductor chip that measures the pressure, and this tiny hole is at risk of being blocked by oily deposits. Cleaning isn't impossible, but these parts are relatively cheap so replacement is probably the better option.
 
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Fredastaire

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Thanks @Anthony489 , the next thing is to find out how to reach the MAP, (its the later Euro 6 twin electric servo drive EGRs engine), there is another post of second hand info of changing the throttle body suggesting a specific repairer does it in one hour. This must define that you dont need to remove all the front end headlights / panelwork / slam panel. if this is correct then half hour should remove the throttle body allowing immediate viewing of the MAP to unclipping connector and removal. Given I'm just awaiting the Postman to deliver the new Fiat genuine MAP thats paid for, there doesnt seem much point in attempting to clean and re-use the original because of the consumed time if I have to access it a second time. I'm also intending to use Holts aerosol carb cleaner to flush the throttle valve before re-fitting. The biggest problem in all of this is that its an intermittent fault so I will need a few days driving before ive any confidence that its sorted. Our Van is a camper van so only used for odd days out during the winter period.
 

Anthony489

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Hi

I once changed the throttle body on my 2008 van, see this post for details and photos: https://www.fiatforum.com/threads/p0638-logged-ocasionally-ideas.481962/

As your van is much newer, there may well be differences, but it will give you some idea of what's involved. If you have good tools for working in a restricted access, and the fasteners aren't seized, then the throttle body can be removed easily. In my case, one of the fasteners was seized (and the bolt head sheared off without much force) and had to be drilled out so I needed good access. To be honest, nothing was too difficult and having done the job once I would be much quicker a second time knowing how it all fits together. The headlights can stay in place on the X250 model.

The main snag was that the van (motorhome) was too tall for my garage so I was forced to work outdoors under a big patio umbrella !

Go steady with the carb cleaner, you don't want solvent working its way past the spindle O-ring seals. You might find it just as effective to spray it on a rag first and rub away any oily dirt from the plate and housing, especially the bit where the plate touches when fully closed.
 
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Fredastaire

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Umm that's a bit scary, bolts shearing off. I think my inlet manifold from memory is plastic with threaded inserts. I've had a look at a new throttle valve on Coastals website, it looks as if there are only three fixing screws, probably m6 cap heads. Every thread I undo gets a smear of coppaslip grease on reassembly. I'll take another look in daylight tomorrow. Ours as mentioned is a campervan, not only will it not fit our garage for height, we cannot open the cab doors as the drive is narrow! Van access is thro the rear doors and central isleway to driver's seat.
 

Crossingkeeper

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It was probably my post regarding the 1 hour changeover time for a throttle body that Fredastaire referred to so I should clarify that my van is a 2009 build with one vacuum-operated EGR. I was surprised at the time quoted as Euroserv has also described it as a 4 hour job, however I was only charged for one hour's labour! (I wish now that I'd stayed and watched him do the job)

Incidentally both the new and old throttle bodies on my van are fixed by 4 set bolts.
 
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Fredastaire

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I wonder, how do we get Euroserve or Wine0 to add comments?
If I have to remove all the front end (headlights, main grill, main front panel, slam panel then as I've already done it twice, I can do it again, it must be a 1 hour job to disassemble because of the bucket loader of coarse thread torx screws you have to remove. (Then same again to reassemble).
 
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Fredastaire

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MAP changed, turbo solenoid valve changed, taken for a 6 mile run. Smoother start with out hesitation, better power - have I sorted it? Who knows? I’ll have to drive quite a few times as it was an intermittent fault.
 
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Fredastaire

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For the record, here's what i've changed at the moment.

MAP sensor, Fiat part number 050424527, cost £43.07, inside the box the part is Bosch part number 0 281 002 845 price £31.99 on ebay inc postage. If you look at the photo there is an inset of mine as extracted, totally clogged with an oil / carbon sludge. There are plenty of competitor replacements on ebay however is the saving worth it? (edit - The new part is date coded year 2021 which probably explains a supercede to that I took off)

Turbo Boost Pressure Control Solenoid Valve Fiat part number 0055269482 – 001, inside the Fiat box is the OE spec valve part number 55269482 and 7.03003.09 which is Pierburg price £ 45.87 , of the hundreds of valves on Ebay Pierburg, none are visibly the same – except I did find an option from Poland £115.68. notably the original on my van and its new replacement are identical AND the pipe connectors are different diameters so you cant get the pipes on the wrong way around, this, I think , would givemassive boost which could wreck the engine?, the Fiat original (and its replacement), also has a vent pipe on an umbilical which has its own filter at the extremity.

Ive added these notes above just in case it helps any other member in future times.....

Maybe I could have got away with just cleaning my MAP, maybe I didn’t need to change the Turbo Solenoid, Ive longish trips shortly on motorways which have lengths without hard shoulder, having had the ‘Limp Mode’ on a section of M1 with hard shoulder, it was concerning enough for me to want to do the best go at repair.

Only time will tell if ive cracked it. A drive again today proved it to be far more responsive, i'm now of the belief that the turbo vanes were being switched lethargically by the solenoid. Ive read elsewhere that other problems can be compensated by the Boost Solenoid working overtime. The question my mind raises is could the throttle body be erratic defective even though I haven't see any fault code. Ive also had MES connected whilst the engine is running, ive seen both the EGRs following their commands, seen the manifold pressure following set points so at the moment I cannot see any direct malfunctions.

If anybody can comment further please do...
 

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Fredastaire

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Still got problems. Took van for a run locally this morning. Going uphill with foot down a bit, warning sound and dash light, plus the dreaded limp mode.

Stopped, turn engine off, restart and back out of limp so drove home.

The van is livelier than it was before fitting new boost valve and MAP.

MES connected on Laptop, gives codes P0401-61 and P0402-61.

I'm still baffled but thinking. More reading and a spot of YouTube makes me consider removing the inlet manifold (to clean?), and/or change Throttle body and/or change MAF.

There are suggestions that faulty MAF or faulty Throttle can make boost valve work overtime and fail....so one problem might have caused a second and bust the boost valve which of course I've replaced.

Thoughts would be welcomed.
 

Thomas Lypold

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Still got problems. Took van for a run locally this morning. Going uphill with foot down a bit, warning sound and dash light, plus the dreaded limp mode.

Stopped, turn engine off, restart and back out of limp so drove home.

The van is livelier than it was before fitting new boost valve and MAP.

MES connected on Laptop, gives codes P0401-61 and P0402-61.

I'm still baffled but thinking. More reading and a spot of YouTube makes me consider removing the inlet manifold (to clean?), and/or change Throttle body and/or change MAF.

There are suggestions that faulty MAF or faulty Throttle can make boost valve work overtime and fail....so one problem might have caused a second and bust the boost valve which of course I've replaced.

Thoughts would be welcomed.

Hi Fredastaire,

has your problem been solved yet?
I also have the same problem PO401, PO336, PO338...... :-( , Fiat Ducato 2.3 year 2017 EUR6 130ps.
Was changed the EGR, the boost pressure sensor and differential pressure valve replaced....... without success.

Greetings Thomas
 
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Fredastaire

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Dec 19, 2017
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Hi Thomas, forgive me but your English doesn't quite work. I changed the HP EGR, no change, I then changed the MAP and the turbo boost solenoid. Before these changes I also had a Fiat dealer software update, (this apparently is critically important). Since Dec12 I've had no Mil light, no limp mode. I have used a FCR and seen a pending code but it has had no effect.
Can I suggest you get the software upgraded. I'm also in discussion with another UK owner with same faults...he's taken direct communication with Fiat Italy, I don't know the outcome. We are not on our own.
 

Thomas Lypold

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Hi Fredastaire,

Sorry for my poor English, and thank you for your quick reply.
I got the software update on Oct 14 and other checks.
- Checking the injectors
- Checking the HP EGR
- Check the LP EGR
- Check the exhaust line and DPF
But without positive effect.

On Nov 25 I changed the BOSCH 0-281-006-287 (SENSOR EXHAUST PRESSURE).
Since Nov 12 I've had no mil light and no limp mode, until this weekend.... engine light and code P0236, P0238 and P0401.
Noticed, below 4°C outside temperature ( frost mode) there is no error, only from 5°C the error and mil light comes.
I tested this today, it's strange but it's real.
Next week I will contact Fiat Germany, let's see what they say.

I hope we will solve the problem soon.

Greetings Thomas.
 
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Fredastaire

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Dec 19, 2017
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Hi Fredastaire,

Sorry for my poor English, and thank you for your quick reply.
I got the software update on Oct 14 and other checks.
- Checking the injectors
- Checking the HP EGR
- Check the LP EGR
- Check the exhaust line and DPF
But without positive effect.

On Nov 25 I changed the BOSCH 0-281-006-287 (SENSOR EXHAUST PRESSURE).
Since Nov 12 I've had no mil light and no limp mode, until this weekend.... engine light and code P0236, P0238 and P0401.
Noticed, below 4°C outside temperature ( frost mode) there is no error, only from 5°C the error and mil light comes.
I tested this today, it's strange but it's real.
Next week I will contact Fiat Germany, let's see what they say.

I hope we will solve the problem soon.

Greetings Thomas.
Hi Thomas, I really would appreciate to be in contact direct, if that's ok please personal message me with your email address. Our Euro 6 Ducatos are a problem. I'm in touch with another owner on the codes you mention. His Fiat dealer yesterday quoted him £7,500 saying he needs new injectors plus DPF plus LP EGR and EGR cooler!!!!
 

Baz in Kent

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That will be me with the £7.5k estimate, I had the HP EGR replaced which (as predicted by FredAstaire) was a complete waste of money.
I won’t get a response from Fiat Italy until Weds when the woman I’ve been dealing with returns to work.
Legal advice is that I should have recourse to the dealer who sold me the van as the fault occurred within 6 months of purchase (UK Consumer Rights Act 2015).
The Fiat dealer who gave me the repair quote mentioned a Fiat “technical instruction” for the fault codes, I’ve asked for a copy of this as well as a copy of the diagnostics scan report but it suggests a problem well-known to Fiat. I suspect I won’t get the documents but will share if I do.
My van has only covered 15k miles from new, this is scandalous to say the least!
 

Thomas Lypold

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Mar 5, 2022
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Hi Thomas, I really would appreciate to be in contact direct, if that's ok please personal message me with your email address. Our Euro 6 Ducatos are a problem. I'm in touch with another owner on the codes you mention. His Fiat dealer yesterday quoted him £7,500 saying he needs new injectors plus DPF plus LP EGR and EGR cooler!!!!
Hi Fred,
I also really would appreciate to be in contact direct.
my mail adress: [email protected]
 

Thomas Lypold

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Mar 5, 2022
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Location
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That will be me with the £7.5k estimate, I had the HP EGR replaced which (as predicted by FredAstaire) was a complete waste of money.
I won’t get a response from Fiat Italy until Weds when the woman I’ve been dealing with returns to work.
Legal advice is that I should have recourse to the dealer who sold me the van as the fault occurred within 6 months of purchase (UK Consumer Rights Act 2015).
The Fiat dealer who gave me the repair quote mentioned a Fiat “technical instruction” for the fault codes, I’ve asked for a copy of this as well as a copy of the diagnostics scan report but it suggests a problem well-known to Fiat. I suspect I won’t get the documents but will share if I do.
My van has only covered 15k miles from new, this is scandalous to say the least!
this is truly scandalous.
My Fiat dealer gave me an estimate of €3,800 for: LP EGR, EGR cooler and DPF, that's a bargain !!!! :)!! no no no.
My car has 52000km, but that's not much for a diesel engine.
I think all EURO6 engines with LP EGR and without AdBlue will have this problem at some point.
I hope we can get away without any big costs.
 

Baz in Kent

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Mar 7, 2022
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Location
Kent
Has anyone else approached Fiat for a response?
Anyone else heard of the Fiat “technical instruction”?
Are all our vans comfortmatic transmission (i know FredAstaire’s is)?
Is there possibly a software issue to do with the emissions scandal affecting VW and Benz?
I suspect any possibility of financial help/goodwill from Fiat will be down to vehicle age/mileage/service history and pressure through social media/press, the more people that get involved the more pressure.
 
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