Technical Twin EGR issues - 'EGR Cooler Syndrome' Symptoms but different Fault Codes - HELP!

[Dancingbear]

Hi all,

I’m hoping someone here might be able to shed some light on ongoing issues with my 2019 Fiat Ducato 35 Multijet II (250) ‘Sportivo’ twin-EGR, no AdBlue, currently on 84,000 miles.

Symptomatically they seem to mirror the EGR cooler syndrome that’s been well documented here, but none of the codes are the same: Over the last 8 months I’ve had the following fault codes:

March
P0683 – glow plug circuit - replaced
P0639 – throttle valve control - cleaned
P045E – EGR - HP replaced (in error)?

May
P045E – EGR - LP replaced

Aug
P041A – EGR temp sensor replaced

Spetember
P2002 – DPF efficiency below threshold (after failed motorway regeneration)

The first motorway journey after the Temp sensor was replaced, a DPF regen failed which initiated the P2002 code and EML.

Unfortunately these error codes have taken excessive times to be fixed and the van has been driven with the EML on – the Temp sensor code illuminated in the French Alps and we weren’t able to get it resolved until back in the UK – 1000 miles+… I now know the illuminated EML will prevent auto DPF regen .

Last week I had a mobile DPF specialist perform a diagnostic and clean at my home. The basics of his assessment were:

Parameter	Pre-Clean	Post-Clean
DPF soot load (%)	177	9
ΔP at idle (kPa)	0.4	0
ΔP at 2500 rpm (kPa)	2.2	0.7
Engine temp (°C)	80	94
MAF (mg/stroke)	448	386
EGR position (%)	0	0
EGT (°C)	628	184

He noted soot present in the tailpipe (which I noted 6 months ago) and suggests the DPF is probably damaged (based on soot and zero / low DPF pressures).

As a massive curve ball to this already complex picture, the DPF guy found my turbo electrically unplugged – which must be from previous garage work - Time scales unknown. Once reconnected, turbo faults cleared and it appears to boost normally again – both on the road and on the diagnostics.

At this stage, I think I know the following:

• This is going to be expensive!!!
• The DPF is almost certainly damaged and I have had soot in my exhaust for 6 months +
• The Turbo unplugged issue could be the root cause of this, as I imagine poor operation of the variable geometry in the turbo will make its operation ‘agricultural’ causing excessive soot! But it could also be only contributory or a complete red herring if it was only unplugged a few weeks with limited miles!???

So, I’m trying to avoid the usual “parts cannon” approach discussed on here and get to the cause rather than treating the symptoms.

I’ve purchased MultiECUScan - its in the post - so I can start logging and learning from the excellent posts many of you have already shared here. I’ve started reading through the twin-EGR and P0401/P0402 mega-thread, but because of the difference in presentation any different or targeted insight here would be hugely appreciated.

Before I dive in, some questions for you legends:

• Do these symptoms and readings suggest solely a cracked DPF or something else upstream (MAP / boost solenoid / EGR control, cooler etc etc.)?
• Would you DEFINITELY have to unplug the turbo to change LP or HP EGR or EGR Temp Sensor and therefore not plugged back in my my local garage?
• Whats the significance of the unplugged turbo?
• How would I be able to ‘prove’ that the garage left it unplugged?
• Any pointers on the next steps or first parameters I should log with MES to narrow this down?

I am not a mechanic of ANY sorts and have had a steep learning curve already – and I’m trying not to be driven into an early grave by this...

I’d really appreciate any informed thoughts or guidance on this!

Thanks in advance

 

[theoneandonly]

These 2 guides will be a lot easier to read than 60 or more pages

Twin EGR Problem

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

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

Take screen shots of all current error messages and the freeze frame data for each)
Try this template
Start from cold and run for 20 mins if possible 10 mins at 60mph (motor way ideal)

No guess work from me until I've seen some data. Is it a 130 or 150? Many reasons for regens not occuring. @Fredastaire @bugsymike any idea about the unplugged turbo?

 

[theoneandonly]

 

[Dancingbear]

Amazing thankyou - Yes i've read both those guides but will need to do so a few more times to absorb the detail. I'm just about to go away working for a week or so, so it'll take me a few weeks to get the data but i will get onto it soonest!

I think my van is a 150 bhp, and hopefully i can come back with confirmation of the software version etc once ive got the MES up and running.

There should not be any fault codes at present because the DPF guy deleted them, and it completed the regen ok post wash despitre the low pressure etc.

The fault codes at the time of diagnosis / pre wash were:
P24A4-68 Soot load and Mileage with DPF lamp on
P2562-14 Variable Geometry Turbo Position Sensor - this cleared imediately when the connection was remade!

Very much appreciated!

 

[theoneandonly]

Thanks the P2562-14 Variable Geometry Turbo Position Sensor imedeately says 150 or 180, the 130 doesnt have a VVT Variable Vane Turbo.

 

[Dancingbear]

@theoneandonly, thanks for waiting, The van is a manual on software v.28, 147.5 bhp. I did the road test as requested above, and there were no fault codes initially. Please see attached 3 files as follows:

File 1: 20 minute road test - started from cold.

File 2: 20 minute road test plus 10 mins @ 60mph (because of where i live its not feasible to do 10 mins @ 60mph in a 20 minute drive)

Just after I finished recording this, the Engine Management Light came back on: P2112-73 Motorised Throttle, Actuator stuck closed. The van went into limp mode, and because I was already configured with MES I just started capturing data again, Hence:

File 3: 10 mins driving with EML on. Also attached is the freeze frame data for that Fault Code event. I understand that the throttle body could possibly be cleaned to return it to normal function or it could require further new parts - does this sound reasonable? I've also recently spoken to a main dealer for their thoughts who have recommended that DPFs don't crack on these vehicles unless exposed to thermal shock - for example from driving through deep water when hot!!?? They went on to say either injectors or a damaged DPF are the only likely root causes for soot in the tail pipe

Let me know if there is anything else you'd like to see to build a picture of whats actually the root cause fault!?

The most obvious questions I have right now are:
1) is the DPF actually damaged?
2) are the injectors (or something else) more likely to be causing these issues?
3) the best way to move forward?

Very much appreciating your help and looking forward to hearing your thoughts!

 

[theoneandonly]

A sooty exhaust is typicaly indicative of a cracked or molten DPF.
There are other charecteristics of a blocked LPEGR that you do not have.
The LPEGR valve reacts as expected and the Temperature is lower than expected but not in the obvious blocked region. This would be expected from reduced exhaust gas flow. The actual air input is not greater than the desired which can be typical of a blocked cooler
All sensors tested work in the expected manner. The HPEGR and LPEGR generaly follows the required values. The differential DPF values give no cause for concern. The fuel values also follow desired. Do not rush to change the LPEGR cooler
The turbo actual values do not always achieve the desired and does not perform as expected. This is time for @deejays template and some one who knows the VVT turbo. As to your question is
1) is the DPF actually damaged? DPF compromised probably
2) are the injectors (or something else) more likely to be causing these issues? injectors/turbo. Excessive sooting due to injector issues Do a injector leak off test.
3) the best way to move forward?
use @deejays template and some one who knows the VVT turbo.

 

[Dancingbear]

I've just had the AA come out to look at the throttle body - it started loudly and constantly clicking as the flap was hunting or jammed or something when ignition was turned on.

He removed the throttle body and opened up the casing - it was corroded inside and showing obvious signs of water ingress. The plastic cogs were intact, the 'flap' was a bit dirty but it moved freely... the electrics smelled of burning! Pics below...

Although i find this a bit hard to believe, I assume this is has to be purely coincidental and not part of my bigger picture???

Or could this be the root cause if it had been sub optimal for some time?

I can see from the data captured this afternoon that the actual air intake was often twice that of 'desired' air intake at lower speeds / revs - but this pattern continues even when the van is in limp mode with TB closed.

I will buy a new one and fit it, hoping it will work fine...
fingers crossed!

 

[theoneandonly]

The Throttle Body being a problem on older Ducatos is a well known, this is the first Ive heard of in this generation. As usual water ingress is the issue. Take the engine cover off and look for Rust and corrosion around the injectors.
edit note the graphs titles are swapped.

 

[Dancingbear]

I've had the cover off, they looked damp and a bit dirty but no obvious corrosion - I cleaned it up and occasionally spray some lanoguard or acf 50 in that area... I have sealed the Scuttle tray with sika and tape but it still gets wet in there occasionally. I'll have another look tomorrow - presumably there could be corrosion in that area which would lead the injectors to operate sub optimally?

 

[theoneandonly]

The main problem with corrosion is the ease/ difficulty of removing the injectors

 

[Dancingbear]

Thanks for all the info! Looking at the graphs in #9, i'm not sure what they're telling me... should the green 'throttle valve' line follow in some way the engine speed or gas pedal values?? they look completely separate of each other!? So does this mean the throttle valve has been operating poorly throughout the data gathering? Possibly for a really long time???

Reference your previous point you said of my data that 'The actual air input is not greater than the desired which can be typical of a blocked cooler'... i noted that often at lower revs / speeds that the actual air is often 200% of desired, but this resolves at higher speeds / revs (see table image)... this is also evident on your graph on the first 20% of the timeline. Is this significant? and overall does this suggest the cooler is blocked, or NOT blocked??

Thanks so much for your help mate, Truly invaluable!!!

@deejays do you have a template that @theoneandonly mentioned above that you'd be happy to share? Any ideas to move forward with assessing the VVT Turbo? Huge thanks in advance.

You guys are LEGENDS

 

[theoneandonly]

Forget the words ( too easy for me to getconfused) this is an example of a blocked lpegr

same data shrunken Y axis





On lefthand side the actual is much greater than demanded then we get the extreame demand that would throw a P0401

 

[Dancingbear]

Forget the words ( too easy for me to getconfused) this is an example of a blocked lpegr
View attachment 475369

same data shrunken Y axis





On lefthand side the actual is much greater than demanded then we get the extreame demand that would throw a P0401View attachment 475370

Ah i see, so a blocked cooler makes unattainable demands for air because its being suffocated (the red spikes) - and this triggers the P0401, which i do not have!? So, reference my post at #12, the differences i've highlighted between actual and desired are not significant enough to be troublesome then?

Seeing these graphs for contrast against my data explains a lot! Thanks

 

[theoneandonly]

Ah i see, so a blocked cooler makes unattainable demands for air because its being suffocated (the red spikes) - and this triggers the P0401, which i do not have!? So, reference my post at #12, the differences i've highlighted between actual and desired are not significant enough to be troublesome then?

Seeing these graphs for contrast against my data explains a lot! Thanks

Thats a much better way with words than what ive got.

 

[Dancingbear]

Thanks for all the info!

Looking at the graphs in #9, i'm not sure what they're telling me... should the green 'throttle valve' line follow in some way the engine speed or gas pedal values?? they look completely separate of each other... So does this mean the throttle valve has been operating poorly throughout the data gathering? Possibly for a really long time???

I've got a new Throttle body on the way... If i ran a diagnostic with Throttle valve, engine speed and gas pedal parameters what would a 'good' graph look like?

Or is the 'throttle valve' and 'throttle body' different? I thought i read somewhere that this vehicle has multiple 'throttle components in different places?

Thanks

 

[theoneandonly]

Or is the 'throttle valve' and 'throttle body' different? I thought i read somewhere that this vehicle has multiple 'throttle components in different places?

Nomenclature (naming) of the bits and pieces that control air and fuel is a bloody nightmare, you will have some people say there is no such thing as a throtle body on a diesel. MES does name some things slightly different to norm but in this instance I take valve as being part of the body. Its only on the graph to show it moves independantly of the pedal. Typicaly described to be there only to control engine shutdown. If it has an important use other than this someone else may advise.

 

[jackwhoo]

Throttle plate also affects quantity of exhaust recycled through engine . Plate closing increses exhaust gas recycled through intake

 

[Dancingbear]

Thanks both.. every day a school day!

 

[deejays]

Nomenclature (naming) of the bits and pieces that control air and fuel is a bloody nightmare, you will have some people say there is no such thing as a throtle body on a diesel. MES does name some things slightly different to norm but in this instance I take valve as being part of the body. Its only on the graph to show it moves independantly of the pedal. Typicaly described to be there only to control engine shutdown. If it has an important use other than this someone else may advise.

As Jackwhoo has said - it not only shuts off completely as part of the engine shutdown (to reduce shudder etc), but plays a very important part in the HPEGR valve throughput (directing gas flow from the HPEGR valve) and thus the complete gas flow of the motor. @theoneandonly there are so many actuators and feedback loops - which is the reason why I urge you to take on a more holistic approach to analysis, as to compare just a couple of parameters in isolation can prove difficult, particularly when an engine has borderline issues. (It is very easy to spot a completely blocked cooler - but more difficult if it is only partially blocking.