Forced DPF regen £200!

[jimmywease]

I'm rather unimpressed that my 2017 T6 Beach recently went into limp mode, with dpf light on and glow-plug warning lamp flashing. I took it into the dealership and their investigation has revealed 'fault P2463' which apparently means 'dpf restriciton'. The vehicle is showing 42.9g of soot in the dpf, although they weren't sure what weight of soot is unacceptably high until further into their investigation...

The upshot is a minimum charge of £166+vat for investigation and a forced dpf regeneration, with the delightful possibility of further (much higher) charges if unsuccessful.

I'm in two minds really:
On the one hand, the vehicle had plenty of short-journeys during it's first year: 200 miles as a dealer demonstrator, then part-time use for school runs etc (although I usually used the Golf) with occasional long runs. It's second year was better: 35mile motorway commutes and longer runs, camping in Wales & France. I've probably driven too sedately for much of the time, conscious of fuel consumption and child-safety. I've also probably allowed the fuel tank to get too low a few times, instead of keeping it 1/4 full. The DPF light has come on a couple of times before, so I've followed the advice and cleared it. I suppose £200 for unclogging it isn't too bad, given that it only needs a service every 20,000 miles.
On the other hand, it's frustrating that I've spent a small fortune on a vehicle AND paid for the extended warranty, only for it to limp into the garage for five days (it happened on a Friday morning). Also what if the dpf needs replacing and that £200 becomes £2,000? Is this really acceptable or should I be contacting VWCS?

Sorry if I'm going over old territory, but I couldn't see much on the non-warranty aspect of dpf issues.

 

[Loz]

Ours went into limp-home mode for this reason but it was caused by a faulty DPF sensor which was preventing the vehicle from doing regions this was all fixed by VW assist and I was not charged for any of it.
I would argue that you have no way of knowing whether it is regenerated successfully or not, you also don't know when it is doing a regeneration, so how can you be responsible for the fact that you've been using it for short journeys which is what you purchased it for?

 

[MattBW]

I believe for the regen to be effective, it needs to have over 1/4 tank, be above 40mph, around 10 minutes about 12 miles and you need to have the revs between 1800 and 2500 rpm. It triggers about every 300 miles.

You can usually spot when regen is occurring, the stop start will stop working, the revs will be a little higher and the MPG will decrease. If you notice this, its good to let if finish.

Ultimately it will come down to driving style and trip types, only you can can really answer that. 35 mile commutes should be good but those early trips don't sound ideal for this kind of engine, school runs and such will clog them up and the soot has built up. A lot of folks drive a diesel carefully for max mpg and as I learnt with my last car this clogs up the dpf even more without a regular good run.

I take mine for a good run at least once a month and try to keep within the rev range not under or over. 4 years and so far so good never seen that light come on. Even then its really hard to know...

 

[jimmywease]

Thanks for the advice guys. I'll keep my fingers crossed that it will turn out to be a fault hence under warranty. I'll also keep my toes crossed that it doesn't need a new dpf!

In future, I'll be sure to keep the fuel over 1/4 full. Looking at the advice in the manual, I'd be surprised if my short-runs had led to this issue, as we live in the country, hence 45mph for 15mins is a short run for us.

 

[2into1]

Here again we wander into confusion over the completely different regenerations of the T6 and the T5. So long as you keep the 1/4 tank rule (which VW only came up with after printing the user manuals), then the T6 will start it's regen as it sees fit. It doesn't need long runs or high revs for sufficient temperatures (like the T5).

Unless you've routinely left it I under a 1/4 full, then I'm failing to see how it's anything other than a warranty issue

 

[jimmywease]

Thanks 2into1.

It sounds like running the tank down too low has probably caused the issue. I was completely oblivious to the 'no lower than 1/4 tank' rule until I started reading the forums today. I was only following the 'Never allow the tank to run completely dry' in the manual. The manual does also say 'avoid making only short journeys.'

I think it is a bit rich to have to pay £200 for not following advice that was apparently omitted from the manual (or is the 1/4 tank rule stated elsewhere?)

It also seems a bit odd for the last 20 litres of fuel to be essentially off-limits. Why not adjust the range reading to hit 0miles at 1/4 full? I suppose because it would make the dpf / VW look silly...

 

[TripleBee]

It doesn't need long runs or high revs for sufficient temperatures (like the T5).

142000 km, almost 10 years old. Used as daily driver for 12!! km single run.
Regeneration happens mostly when driving a constant speed, let's say 90 km/h in 6th gear, so about 1600 rpm.
No use to drive in high revs. Then the regeneration will not start because the revs are too high.
Ideal rev spectrum is about 1800 - 2000 rpm. That would mean, ideally, when driving 90 km/h, I should drive in 5th gear.
I sometimes have a regeneration when driving 50 km/h in 4 th gear. So nowhere near high revs.
The highest revs I get on the motorways driving approx 110 km/h, so just under 2000 rpm. Then I feel a continuous regen (small holdup, and then back to normal, and again, and again,...) for a minute or so. Then a whole time nothing, then again, till it gets over.

Don't know how the regen feels in the T6?

 

[Amarillo]

Thanks 2into1.

It sounds like running the tank down too low has probably caused the issue. I was completely oblivious to the 'no lower than 1/4 tank' rule until I started reading the forums today. I was only following the 'Never allow the tank to run completely dry' in the manual. The manual does also say 'avoid making only short journeys.'

I think it is a bit rich to have to pay £200 for not following advice that was apparently omitted from the manual (or is the 1/4 tank rule stated elsewhere?)

It also seems a bit odd for the last 20 litres of fuel to be essentially off-limits. Why not adjust the range reading to hit 0miles at 1/4 full? I suppose because it would make the dpf / VW look silly...

My understanding is the the problems occur when the tank is rarely refuelled above 1/4 tank.

We routinely refuel to 80 litres, then run down to less than 1/8 of a tank and a low fuel warning light before refuelling. 50,000 miles and no problems.

 

[jimmywease]

Hi Amarillo,
Yes, that would sound more reasonable. I almost always fill to 'full' EXCEPT over the past few weeks, when I've used the van infrequently and on fairly short trips AND I think I've twice put just 20 litres in, simply because I was at super-expensive petrol stations. Unbeknown to me, this may have created a perfect storm of dpf regen frustration...

Perhaps my £2 saving of on diesel will cost me dear...

Thanks for the blog BTW. I'm up to day 300!

 

[TripleBee]

I almost drive to fuel warning all the time.
If I have to refuel I want it to be necessary instead of refuelling every week.
As long as there is diesel in my tank, the engine will keep regenerating.
The newer T6 uses AdBlue to regenerate, so we can't really compare.

 

[2into1]

or is the 1/4 tank rule stated elsewhere?)

They made it up recently. We only know about it thanks to @VW Guru. Apparently the fuel flys around the whole system and returns to the tank all the time. It doesn't just get pumped into the engine (silly us). So the fuel going around the system can overheat with less than 1/4 tank and a (T6) regent takes place.
I wouldn't be accepting any bills within warranty for this.

 

[VW Guru]

I almost drive to fuel warning all the time.
If I have to refuel I want it to be necessary instead of refuelling every week.
As long as there is diesel in my tank, the engine will keep regenerating.
The newer T6 uses AdBlue to regenerate, so we can't really compare.

hi @TripleBee the new T6 does not use adblue to regen it still uses diesel injected on the exhaust stroke to heat the dpf and turn the spot to ash. The adblue is for the selective catalytic reduction system to reduce NOx this is injected upstream of the dpf and mixes with the exhaust gas then goes through the dpf which has a reduction catalytic coating. So the dpf and adblue are two separate emission systems to tackle two separate problems

 

[VW Guru]

They made it up recently. We only know about it thanks to @VW Guru. Apparently the fuel flys around the whole system and returns to the tank all the time. It doesn't just get pumped into the engine (silly us). So the fuel going around the system can overheat with less than 1/4 tank and a (T6) regent takes place.
I wouldn't be accepting any bills within warranty for this.

Hi @2into1 so a little update vw have now released technical info for us to check engine data and providing the data matches the info we have the first forced regen due to running below a quarter of a tank will be covered by vw UK however it’s then the dealers responsibility to inform customers of the way the system works and if the issue happens again due to the advise not being followed then the costs will be the customers. Vw are also producing windscreen stickers for us as dealers to put in every euro 6 vehicle

 

[Legin]

hi @TripleBee the new T6 does not use adblue to regen it still uses diesel injected on the exhaust stroke to heat the dpf and turn the spot to ash. The adblue is for the selective catalytic reduction system to reduce NOx this is injected upstream of the dpf and mixes with the exhaust gas then goes through the dpf which has a reduction catalytic coating. So the dpf and adblue are two separate emission systems to tackle two separate problems

VW Guru. Probably a typo but the Ad Blue is injected upstream of the scr not the dpf. Also by way of clarification does the regen still work without exhaust stroke injection and only utilised if regen conditions need to be helped along.

 

[Legin]

Those of you that want to know whats going on yourself have a look at an app called VAG DPF. It doesnt work on every engine version but tells you exactly whats going. You need an Android phone and a dongle like carista. Not expensive.

 

[jimmywease]

Hi @2into1 so a little update vw have now released technical info for us to check engine data and providing the data matches the info we have the first forced regen due to running below a quarter of a tank will be covered by vw UK however it’s then the dealers responsibility to inform customers of the way the system works and if the issue happens again due to the advise not being followed then the costs will be the customers. Vw are also producing windscreen stickers for us as dealers to put in every euro 6 vehicle

Thanks VW Guru. This makes sense and explains why the dealership firstly made me write a statement on the job card, explaining the sequence of events and secondly kept banging on about missing codes in the system. They seemed to think that some codes had been deleted, possibly during vehicle recovery. The vehicle has never been touched by anyone but them and the the dealer it came from. I suggested that they might have deleted some codes a month ago, when they had it in for a broken coolbox and also carried out campaign 23Z7. They thought not.

Sounds like this will get more and more complicated. I’m already out of my depth reading your regen explanation!

 

[VW Guru]

VW Guru. Probably a typo but the Ad Blue is injected upstream of the scr not the dpf. Also by way of clarification does the regen still work without exhaust stroke injection and only utilised if regen conditions need to be helped along.

Hi actually not a typo we now use a combine dpf and scr cat the exhaust gas flows out of the engine through the oxidization cat then down past the adblue injector through a mixer and then through the dpf/scr cat. The engine management changes the injection when in regen wether forced or during normal driving normally consisting of two pre injections, 1 main injection and 1 post injection to heat the dpf on the exhaust stroke.

 

[Legin]

Thanks for the clarification on the Ad blue injection Guru. Am I right in thinking that the 1 post injection came in from the EA189 fix update and therefore applied to Euro 6 etc

 

[VW Guru]

Thanks for the clarification on the Ad blue injection Guru. Am I right in thinking that the 1 post injection came in from the EA189 fix update and therefore applied to Euro 6 etc

Hi we have run post injection since 2010 and the introduction of common rail engines. The ea189 fix changed the frequency of regens and the way in which egr is used during the regen phase as well as other software tweaks

 

[Meoncoast]

So if I am reading some of the above right. I should not let the take go below 1/4 full.(which to be honest I rarely do) BUT when I have normally on a long trip and the computer say "ping" low fuel warning 70miles range - and the nice expensive sat nav asks me if I want to find the nearest fuel station. It is all a bit late then if I am not advised to run with less than a 1/4 of a tank. Why does the van computer not flash me a warning ping "you only have a 1/4 of a tank fill up now or you will have a problem?

 

[Amarillo]

So if I am reading some of the above right. I should not let the take go below 1/4 full.(which to be honest I rarely do) BUT when I have normally on a long trip and the computer say "ping" low fuel warning 70miles range - and the nice expensive sat nav asks me if I want to find the nearest fuel station. It is all a bit late then if I am not advised to run with less than a 1/4 of a tank. Why does the van computer not flash me a warning ping "you only have a 1/4 of a tank fill up now or you will have a problem?

The problem that the OP had was a prolonged period of not filling above 1/4 tank.

 

[jimmywease]

A quick update:

Following completion of the work, I made another attempt to argue that it shouldn’t be chargeable, citing the prolonged sub-quarter-tank fuel running of the vehicle as being almost certainly the reason for the dpf regen failure. Running the vehicle in this manner is not advised against, in the manual. The dealership conceded that the fuel-level was the most likely cause but reaffirmed that it wasn’t covered. I told them that I wouldn’t collect the vehicle until I had spoken with VWCS.

I then had two discussions with VWCS, over two days. The second discussion only resulted in an investigation being opened, with an outcome expected the following week.

Four hours later, I got a call from the dealer. No charges for the work. Goodwill from the dealer!

I’m not certain of the mechanics of this outcome. I find it a bit odd that the dealership is apparently taking the hit for the forced dpf regeneration. Perhaps it was just not worth the parking space in a crowded dealer compound, given that the vehicle came into them unannounced on 11th October and was going to sit there until VWCS came back to me on 24-25th October!

I collected the vehicle and thanked them. Then as I had a cursory look around its bodywork, I noticed that the month-old lacquer-and-buff repair of a scuff now looked worse. Never mind, I thought, the lacquer must have come off during the complimentary clean. But wait - isn’t that scuff on the wheel arch, just where the sliding door opens? Didn’t I see something on the forum about that issue? Raised it (very politely) with the dealer. Back next week for investigation...

 

[VW Guru]

A quick update:

Following completion of the work, I made another attempt to argue that it shouldn’t be chargeable, citing the prolonged sub-quarter-tank fuel running of the vehicle as being almost certainly the reason for the dpf regen failure. Running the vehicle in this manner is not advised against, in the manual. The dealership conceded that the fuel-level was the most likely cause but reaffirmed that it wasn’t covered. I told them that I wouldn’t collect the vehicle until I had spoken with VWCS.

I then had two discussions with VWCS, over two days. The second discussion only resulted in an investigation being opened, with an outcome expected the following week.

Four hours later, I got a call from the dealer. No charges for the work. Goodwill from the dealer!

I’m not certain of the mechanics of this outcome. I find it a bit odd that the dealership is apparently taking the hit for the forced dpf regeneration. Perhaps it was just not worth the parking space in a crowded dealer compound, given that the vehicle came into them unannounced on 11th October and was going to sit there until VWCS came back to me on 24-25th October!

I collected the vehicle and thanked them. Then as I had a cursory look around its bodywork, I noticed that the month-old lacquer-and-buff repair of a scuff now looked worse. Never mind, I thought, the lacquer must have come off during the complimentary clean. But wait - isn’t that scuff on the wheel arch, just where the sliding door opens? Didn’t I see something on the forum about that issue? Raised it (very politely) with the dealer. Back next week for investigation...

Hi yes the dealer would end up taking the cost Luckily it’s only time and no parts but still ends up costing us as dealers due to a mistake by vw not explaining the quarter of a tank rule in the manual. As for the scuff on the wheel arch there is technical information out for dealers in adjusting the sliding angle of the door. All so the paint work will be covered and needs to go to a vw approved body shop.

 

[Karsten]

I think a little clarification is needed. I've never heard of any limitations regarding fuel (except "don't let it run dry), but my understanding of what's written above is: The regeneration doesn't work if the tank is below 1/4. If you tank to full each time, 3/4 of the time (at least), the tank is above 1/4 and there's plenty of time to regenerate.

 

[MattBW]

The same thing happens with the coolant heater, it will not activate in cold weather if there is less than 1/4 tank.