Looking for advice please... RE: Turbo hose popped, blocked DPF... what came first?

[VR#46GOAT]

Hi all,

Firstly, my apologies for the long post but I want to share as much as I can.

I have a 2019 Caravelle TDI BMT that has only done 53k miles. I've owned it over 2 years and until a month ago it was spot and never gave me any issues. Then I was coming back from dropping the eldest at Uni when the orange coil light came on flashing. Long and short of that issue is that it was diagnosed as needing 4 new injectors and a glow plug, fault code only showed issue on cylinder 2 but the VW specialist sent them away and had all 4 tested, the testing place said they were all dripping apparently (error codes were P067200 and P026600). I took a deep breath and swallowed this, paid for four new injectors and a glow plug.. ouch!
The van ran ok with no warning lights but only for 257 miles before I heard a loud pop and then the sound of rushing air under the dash. I suspected it was a hose so I pulled over and phoned the garage that done the injectors to see what they thought. They wanted to see the van and they suggested it would be ok to drive to them which was around 12 miles away. At this time no warning lights were on the dash. About 10 miles into the journey to the garage the coil light came on and the van entered limp mode, within another 3-5 miles it gradually lost power and eventually I had to pull over on the side of the carriageway (no b**dy hardshoulder!! ). I got recovered to the original garage and left the van with them to assess.
Next day I got a call saying that the exhaust is blocked and the engine cannot breath, this was confirmed by them taking the exhaust off the engine and it starting and running. The diagnosis is a blocked DPF. The cause I am told is a result of the original faulty (drippy) injectors, this blocked the DPF which in turn created too much pressure in the system causing the turbo hose to pop off, I am told the clip holding the turbo hose on is fine and as it should be.
The consequential costs to supply and fit a new DPF exhaust, plus diagnosis, plus, plus is similar to the cost of the extension Trump is putting on the White house!!
Its stressing me out big time as its a serious amount of money that we didn't budget for and its led me to many questions that I cannot answer and was hoping there may be someone who could offer some advice on here .

1, Do you have to take the turbo hose off when replacing injectors or glow plugs? I am wondering if the hose clip was not secured correctly.
2, There was no coil light or other warning lights that were present when the hose came off the turbo. I am wondering if there would have been a warning light (coil or similar) if the DPF was blocked and creating that much back pressure. Would the turbo hose blow off with no warning lights on dash saying something is up?
3, Is it worth to get the DPF cleaned? The garage says that its never 100% and its better to buy new.

I read on here that if you run the engine with a turbo hose not connected the fuel mix will be wrong and cause the DPF to block...
So, its ultimately a question of chicken and egg? Did a blocked DPF (no light on dash) cause the turbo hose to blow off.. or.. did the turbo hose come off and this caused the DPF to block as I was driving to the garage?

And... is there anyway to prove either way?

Any help you can offer is super appreciated.

Thank you

 

[DXX]

IMO you guessed right but hard to prove.

The induction hose has to come off, VW recommend it’s replaced as can be issues re-using unless replaced carefully.
Driving the distance normally aspirated would have caused incomplete combustion and a huge quantity of soot which may have blocked the DPF.
Some get the DPF cleaned but if you are going to do it give it to a specialist who should provide some warranty.
My advice would be to change the oil / filter as well due to the amount of soot.

There is a waste gate on the turbocharger assembly to vent excess pressure.

 

[VR#46GOAT]

Thanks for your help. Much appreciated. As you say... hard to prove.

 

[mmi]

2019 Caravelle TDI BMT

Exactly what engine - code on sticker under dash by steering column. E,g, CXGB, CXHA,...

taking the exhaust off the engine and it starting and running.

Do you mean engine didn't start/run without taking the exhaust off?

I read on here that if you run the engine with a turbo hose not connected the fuel mix will be wrong and cause the DPF to block...

It's diesel engine - it runs always with excess air. It even has a sensor in the exhaust to monitor remnant oxygen.

Even more so when a fault has been detected - the engine changes it's operation to "backup" mode - opens intake airways fully and closes exhaust recirculations - so no extra stress for the DPF. However, keeping on driving several hundred miles would eventually cause excessive soot to accumulate in DPF because engine can't do DPF regeneration with active fault.

 

[VR#46GOAT]

Hiya, the van is at the garage so I cannot confirm the code exactly, the V5 says engine number is CXEC 09xxxxx.
Engine would start but then die within 10-20 secs without exhaust off.

I only drove around 8 miles with the hose off at steady speed of around 50mph.
The coil light only came on in last couple of miles when it switched to limp mode. Turbo hose came off with no fault codes showing and no immediate limp mode. Thats what is making me think the DPF was not blocked before the turbo hose came off.
Do you know if you have to remove the turbo hose to get replace injectors/glow plugs?

Thanks for your help.

 

[mmi]

CXEC

Ok - that's the code

Do you know if you have to remove the turbo hose to get replace injectors/glow plugs?

Yes, definitely need to remove the hose to get access to injectors.

Engine would start but then die within 10-20 secs without exhaust off.

Did you experience yourself the engine dying?

Turbo hose came off with no fault codes showing

Any codes at the garage?

 

[VR#46GOAT]

Yes I was driving to the garage when the engine slowed and then died. It didnt sound too good before it died, after it died it would turn over and start but only momentarily. Garage have since started engine after removing the exhaust and say its ok but my fear is they cannot tell with exhaust disconnected due to the excessive noise.
Only code at garage is faulty DPF (don't know exact codes but ill try to find out tomorrow).

Do you know if its possible to have a blocked DPF without error code on dash?
Would a blocked DPF cause a turbo hose to pop off?

Thanks

 

[mmi]

Would a blocked DPF cause a turbo hose to pop off?

The DPF is on exhaust side of the engine. Turbo hose in on air intake side. Only (tiny) passage between them is the EGR. For me it's very difficult to imagine how it would be possible. Such an excessive pressure (to pop a hose off) in air intake would have likely triggered overboost fault code into fault log. Also the hoses are secured with jubilee clips - they won't just pop off - I would expect hose burst well before that, or intake manifold to crack, etc.

Do you know if its possible to have a blocked DPF without error code on dash?

No, I don't think so. At least the situation would have been logged into fault memory - very early actually. Also would have expected to see DPF warning light on dash as an indication of failed DPF regenerations (ECU periodically cleaning any blockages in the DPF).

Would be more than helpful if the garage could extract ECU memory data dump - also called as engine blockmap data (usually made by VCDS diagnostic tool - e.g. as in Rough idle / potential misfire after EGR replacement, probable causes? VCDS logging approach?

Only code at garage is faulty DPF (don't know exact codes but ill try to find out tomorrow).

Hmmm... turbo hose popping off should have created quite a few of them

2019 Caravelle TDI BMT that has only done 53k miles. I've owned it over 2 years a

How many miles in your ownership?
What kind of journeys have you done - only 10 minutes or less?
Have you noticed any DPF regenerations - high idle at 1000RPM, radiator fan running after engine has been stopped?
Any calculated fuel consumption figures (actual fill-ups vs. actual miles)?
Do you know the history before your ownership?
Any possibility that the ECU has been remapped - e.g. do you have AdBlue range displayed on your dash?

 

[VR#46GOAT]

I've done 16k miles over 2 years, mainly short trips but 2 mnths ago took it around Europe so had plenty of motorway miles.
Local journeys tend to be 10miles or less.
Yes I have heard radiator fan running after engine stopped. Not always but certainly have noticed it on occasion.
Fuel consumption seems normal.
I don't know history of van as I bought from a dealer but its only done 53k miles, had done 37k miles when I bought it. Full service history and last service was around 4k miles ago before the Europe trip.
Yes ECU has been remapped, EGR and AdBlue deleted.

Appreciate your time on this, thank you.

 

[mmi]

Yes ECU has been remapped, EGR and AdBlue deleted.

That's interesting How many miles since the remap?
Now defnitely need to see engine's blockmap data - to see what ECU thinks about soot and ash accumulation in the DPF as well as DPF regen statistics.

 

[DXX]

Mentioning the EGR and adblue remap in post #1 would have been wise

 

[VR#46GOAT]

Yes sorry, in hindsight, I should have mentioned the remap but didn't think, was more focused on the recent activity regarding injectors and glow plugs.

Remap was done around 1k miles ago, this was done as the AdBlue counter stayed on 150miles even though I topped it up with 10ltrs.

So history of events.
Around 1k miles ago coil light came on and AdBlue wasn't counting correctly. Took it to my local VW dealer was reticent to get involved as they mainly work on cars and had trouble diagnosing these faults in past. Hinted / Suggested that it can be mapped out. Fault codes at the time were P040100 passive/sporadic, P067200 Cylinder 2 glow plug circuit passive/sporadic, P026600 Cylinder 2 contribution/balance passive/sporadic, P220300 NOX sensor bank1 passive/sporadic.
Had the van remapped at tuning workshop with EGR / Adblue delete and stage 1 tune. No error signals after.
Van ran great for around 600 miles until coil light came back on. Error codes were P067200 Cylinder 2 glow plug circuit passive/sporadic, P026600 Cylinder 2 contribution/balance passive/sporadic.
VW specialist replaced 4x injectors and 1x glow plug. No fault codes present.
Van ran for 250ish miles before turbo hose popped off. No error signals on van before this. Attempted to drive van to garage, approx. 7miles into journey the coil light came on and then engine stopped within 3 miles I would say.

I'll ask the garage to print me off the blockmap data. Is this something they should have access to.

Thanks

 

[mmi]

VW specialist

I'll ask the garage to print me off the blockmap data. Is this something they should have access to.

For a VW specialist - I would expect so. Preferably as a file - it's more than 1500 lines of data.

 

[VR#46GOAT]

Is it called a blockmap data file and is it a historical record of the gas flow through exhaust which would indicate if a blockage has been present and got worse?

 

[VR#46GOAT]

Is there a way to tell if engine has suffered more damage other than fitting new/cleaned dpf and running the van?

 

[mmi]

Is it called a blockmap data file and is it a historical record of the gas flow through exhaust which would indicate if a blockage has been present and got worse?

Ross-Tech, manufacturer of VCDS diagnostic tool, has named is as a "blockmap". It's not exactly historical record but accumulated values of various engine parameters - including soot and ash accumulation, simple DPF regeneration statistics, time/distance/fuel used since last regen.

See below how-to generate a blockmap

Post in thread 'Rough idle / potential misfire after EGR replacement, probable causes? VCDS logging approach?'

11 Sep 2025

I’ll be looking to teach myself how to log live data and make analysis via VCDS. Until that wonderful day - might one of you suggest an approach for logging this? The rough idle isn’t concerning, but the potential misfire is.

First things first

Interested to see if we could see anything peculiar in engine data. Perhaps you could post the following please:

1) Full VCDS Auto-Scan
2) Engine blockmap - Ignition ON/engine OFF
3) Engine blockmap - Engine running at idle

How-to create a blockmap file:

[VCDS]​

[Applications]​

...

• mmi

• 

Ross-Tech VCDS HEX-V2 USB package for VW, Audi, Seat, Skoda cars (1996 on, 3 VIN limit)

Ross-Tech VCDS HEX-V2 USB package for VW, Audi, Seat, Skoda cars (1996 on, 3 VIN limit) - only £225.00 including VAT & UK delivery!

www.gendan.co.uk

 

[mmi]

Is there a way to tell if engine has suffered more damage other than fitting new/cleaned dpf and running the van?

Not really - expect tearing down the engine. Anyways, I wouldn't expect to see any damage because of popped off turbo hose or blocked DPF.

 

[VR#46GOAT]

Not really - expect tearing down the engine. Anyways, I wouldn't expect to see any damage because of popped off turbo hose or blocked DPF.

Fingers crossed then...

 

[VR#46GOAT]

Bit of an update on my thread.

Took the DPF to get it cleaned, company who done it sells the equipment and seem very knowledgeable. They said they had never had a DPF as blocked as mine.... They soaked it and flushed it 6 times to get it from over 200mbar to 63mbar. DPF is now back at the VW Specialist garage for refitting and i'm hoping that it can have a forced regen to further clear it. I am expecting van back Tuesday.
I asked the VW specialist for the diagnostic reports suggested by mmi, unfortunately they say they are unable to provide these but have given me the following.

I am no expert but it would seem to me that the dpf was working fine as it had its last regen105mins and 87km since the breakdown.
Are the two soot mass values before and after regen? I am not sure why it list 60g and -0.16g?

This coupled with the fact there was no dpf warning light before the breakdown, and the dpf flush company said they have never seen one so blocked further reinforces my theory that the turbo pipe coming off had caused huge over fueling and masses of soot to clog the dpf.
Any thoughts or other ideas guys?

Thanks

 

[DXX]

Ref post #2.