Adblue and dpf and egr questions

[Ross1]

I’m new to transporter ownership and all this adblue / dpf malarky so please excuse the questions.

At the weekend we took the van on its first long trip from the midlands to Cornwall. All was well on the way down. On the way back up the eml light came on, followed a while later by a warning to fill the Adblue in 650 miles. This is the 1st time I had seen an Adblue warning. After a services stop the Adblue light went out but came on again later. As the van was running ok, we carried on up the road at a moderate pace with the lights still on.

I cleared the fault codes on Sunday - low flow in the egr, reductant system performance, scr nox catalyst efficiency and they have not returned since. Since the Adblue light was still on, and now showing 600 miles I decided to top it up. Despite trying to access the menus I couldn’t find nothing about the amount of Adblue to use so decided to add the 10l thinking this was sufficiently less than the 13l capacity not to cause a problem. With about 1l to go the abdlue started spitting out of the filler neck so I am concerned I may have overfilled it. The Adblue warning light has cleared and the van started normally. Have I caused a problem?

Re the egr valve, I have a receipt showing this was flushed recently. Is this likely to be just a glitch in the electronics or is it something I need to investigate further?

A separate concern - I have run the dpf companion software today. It shows the last regen was over 300 miles ago and the soot is now 93%. Is this normal? I expect it to run a regen very soon. Another concern is the ash residue calculated at 103g. I take it that I should be planning to get the dpf removed and flushed before it causes problems?

For info, the van is a 2017 102 startline with high miles. Apart from what I believe is a strut top bush knocking the van runs well, has a very good service history and was the right price, hence my decision to purchase it. After cruising back up from Cornwall the display showed 65mpg so fuel economy doesn’t seem low, which I have read is a symptom of a clogged dpf.

I was originally using an old code reader but now have the Christa evo. I haven’t had the time to explore all of the menus yet so don’t know exactly what it shows or allows me to access.

I’m hoping you can reassure this newbie.
Cheers
Iain

 

[DXX]

What ‘high miles’, stating the actual mileage would help diagnose?
Not sure what the ‘companion software’ was that you checked the DPF soot level with (93%) but check it again with Carista.
EGR flushes are just are pretty much a waste of time, once the EGR has clogged any flushing medium can’t pass through the cooler. Regard the EGR as a consumable part, it may well need a renewal.

 

[whodat]

If it had a flush - why did it have a flush?
Can you check - Was it the EGR or the DPF that had a flush?
There was a reason they did it and the reason is likely to be that it likely needs a new one whatever it was.

In the steering wheel menu (for T6.1 anyway) you can go through settings and it tells you how much min/max adblue to put in - might not be the same with yours so that might not be helpful in any way.
Can you get a siphon and get a litre of adblue back out of it?

It will only regen if there is more than a quarter of tank of fuel. So fill 'er up £££££££££.
Does it say how many grams of soot there is? More than about 30g means it really needs to have a regen.
How are you measuring mpg? Sounds too good. (sorry to be 'that guy')

 

[Ross1]

Thanks for replying.
High miles - now showing 210k. Known motorway miles and FSH, including recent cam belt and clutch changes. The price was ok given the condition etc.
Dpf companion is a phone app developed by a forum member that takes the data straight from the obd reader and displays it in a dashboard format - just after it hit 30g / 100% soot the regen started. Just for good measure I extended my journey home by a couple of miles so the regen completed before I got home. There didn’t seem to be any issues. The interesting thing to watch will be the mileage until the next regen on my current commuting routine rather than on an extended trip. And yes, it did cost a few £££ to fill up.
No steering wheel menu as it is a poverty spec van. I didn’t have anything suitable to siphon some Adblue this morning so had to just drive and see what happened - no apparent ill effects yet so fingers crossed…
65 mpg was shown on the trip computer. I don’t know how accurate this is, but I did a my 30 mile round trip commute, a Warwickshire to Cornwall round trip and some local miles in Cornwall, but still had 1/4 tank left on the gauge, which I think is pretty good.
Checked the receipts. The egr was flushed last year after they checked the flow. The van was in for inspection following the p.o. having an issue with the Adblue warning not resetting. The receipt shows a pipe and gasket so I assume the egr was removed for cleaning rather than just flushing it through in situ. This was at a vw commercial dealer so I hope they knew what they were doing. I’ll monitor that one and see how it goes.
That really leaves me with the dpf. It seems to be behaving itself but the calculated ash reading is high. While I don’t want to spend unnecessary cash, I would prefer not to be stranded in the middle of a long trip. Can the condition be assessed using pressure measurements across the dpf shown on the carista software? I have had a quick browse but didn’t come across anything beyond a dpf summary saying everything was fine.

 

[whodat]

From what I've seen on this encyclopaedic forum, the DPF (and EGR as DXX says) should be considered to be a consumeable item, same as brake pads etc.
When it reaches a certain amount of ash (have a search there is a recent thread on this) then it will need replacing.
Some people take them out, dunk them in some chemical for a couple days and pipeclean them out but that is above my pay grade. Anything more than changing windscreen wiper blades is a no go for me nowadays.

 

[manfrotto]

Based on what The VCDS blockmap on my van. the Ash content maximum is 110 grams, so yours is getting close to that, which is not surprising at over 200l miles.
The ash doesn't increase that quickly, but definitly something that will need adressing sooner rather than later.
If it were me, I would get a new one installed, unless you can find a reputable place that cleans them.
In the scheme of things they last a very long time - hundreds of thousand of miles.

 

[Bigsidavies]

You aren’t supposed to overfill the ad blu for fear of preventing the sensor from working.
I’ve accidentally brimmed it to overflowing when I used an hgv ad blue pump in France. No harm done and it registered the amount and I carried on. Been fine since.
So I’d say if it’s reset and it’s back to working ok then you’ve got away with it. Be more careful in future.

 

[DXX]

The DPF is a filter, hence the ‘F’. Any filter will clog at an ever increasing rate as the surface area for the medium to pass through is reduced.
To avoid any confusion the ash in DPF is there to stay, that is also blocking the filter along with soot.
You haven’t quite reached the limit but it won’t be long and it may cause other issues. It’s well known that DPF back pressure acts against the turbocharger oil feed, a recipe for disaster.

 

[manfrotto]

Regarding the Adblue if you have the i-phone software for the OBD data, you vcan also monitor the ADblue. Something like thsi:

 

[Ayjay]

@manfrotto. What OBD app is that please?

 

[Linoleum Bonypart]

Not a hope in hell you’re getting 65 mpg …
Sounds like you need a garage to sort egr dpf

 

[manfrotto]

@manfrotto. What OBD app is that please?

this is the thread on what I did to get the display to my I-phone and also via Carplay to the MMI screen in the van.

Thread 'Displaying additional Information on Infotainment screen - How I did it.'

12 Jan 2026

I have added some additional screens on my Infotainment screen via Carplay and i-Phone with Bluetooth connection to an OBD II BLE4 Diagnostic device.
This is how I did it:

1 - I bought a Vgate iCar Pro ELM327 BLE 4.0 -

2 - I downloaded free Car Scanner ELM OBD2

Car Scanner ELM OBD2 – The best car OBD2 diagnostic solution for iOS and Android in your pocket!

www.carscanner.info

3 Plugged the Scanner device into the car and with ignition on paired my i-phone with the scanner.

4 - In the phone App under "Dashboard" I created a new dashboard in the customisable page option and renamed it "DPF status".
Under that new dashboard I added various things to have on...

• manfrotto
• Replies: 10
• Forum: Engine, Gearbox, Exhaust, Drivetrain

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