As per title; dealer says that my Superb Mk III needs a new diesel particulate filter, but the car was new in March 2019 and has done only 52,390 miles.  Is this normal?

 

Here is the recent timeline:

• 03 Aug: Check Engine light came on and stayed on.
• 15 Aug: dealer said DPF regen had failed 3(?) times so I guess they just forced one and reset everything.
• 06 Sep: DPF regenned.  I made sure it completed.
• 16 Sep: Check Engine light came on and stayed on again.
• 24 & 29 Sep: 2 more regens that completed.
• 03 Oct: dealer thinks the EGR cooler might need replacing, but they keep the car overnight for more diagnostics.
• 04 Oct: dealer says the DPF needs replacing!  When she estimated the price, I stopped listening after "3 thousand."

 

FYI I'm just a guy with no DIY skills and no car diagnostic gear (yet.)  Dealer hasn't said what the error codes were.  What would you do in my situation?  Thanks in advance.

Way too early, but could indicate a fault elsewhere (unless car was clocked)

 

For £3k, I would take it off for cleaning.

Well you don't always have to remove to clean it.

First thing i would be doing is finding out EXACTLY what they have done for diagnosis, speak to the tech, write it all down, post it on here.

A copy of the faults that relate to this issue and how exactly they came to the conclusion that there is a fault like this....

 

50k miles and 3 years is no where near the time for a dpf to be full of ash (not soot), so what kind of failure do they suspect from the dpf, is it a collapsed honeycomb or are they just guessing....

@CaptainDun I am guessing the forcing regens were to try and clear the DPF.  It clearly was too full for it to work (but just about cleaned enough to work for short while)

 

What I am unclear on, is if the DPF is full of ash, or has failed and broken up inside thus blocking the exhaust.

 

What is the history of the car, have you had it from new, or did you buy it later (when and what mileage).  What have your journey patterns been like, is it a town runabout, or used for long journeys (or if a mix try and describe them).  This info might help people understand how it might have got the problems and what needs to be done.

 

As @varooom has said might be worth a full clean, before go down replacement route.   Might be worth making a Ceremex enquiry (note I have never used them so no idea if any good)

 

 

Thanks for the responses guys. 

@ApertureS I'll try to get more details.  In a few days I've learned a lot about DPF, EGR etc. from a standing start so I'd like to know exactly what's going on.

@SurreyJohn I've had this car since new (March 2019.)  I always have the transmission in Eco mode and cruise smoothly at 70mph (75 before Putin's war) at <2,000 rpm.  Until March 2020 I was commuting 94 miles a day along mostly motorway.  During lockdown and since it's been local journeys plus fairly frequent leisure trips, again mostly motorway plus cities at the end.

I am just wondering if the DPF has over time filled with ash and soot, and the volume is now too much for a regen to burn off.

 

I might be wrong, but using Eco mode and keeping engine under 2000rpm, is probably not going to get it hot enough to fully clean the DPF.   My hunch is when lockdown started there was already a partial residue that hadn’t been burned off, and the short lockdown journeys added to it.  Subsequently never been able to shift this old stubborn buildup and further buildup has accumulated.

 

I suspect the forced regen cannot clear 3 years of residue, so the only option is to clean (or replace) the DPF unit.  
 

Unfortunately I think your DPF has been collateral damage of lockdowns, not that you could have predicted it, or diesel being about 18p (11%) more expensive than petrol (which with your 14k miles per year average, makes diesel a bad choice due to extra cost).  
 

I think all you can do is try and find a good DPF cleaning company and not going down the dealers expensive replacement route, or waste any more money trying to force a regen (which is only going to be very temporary)

 

 

@SurreyJohn I think our OP is driving above 2,000 rpm from his last post, but you are spot on though about the rev ranges need to be in the correct range.

 

As @ApertureS has mentioned the diagnostic report would be good if he could get hold of it (no doubt they won't supply details to him sadly)

 

I picked up my car this Summer, and driving it back the exhaust light came on (it does this after 1hr if it cannot do active regen) most of my journey was 60mph and not enough rpm to do regen.

 

Once home, I was able to scan the car, and the oil ash was fine, but soot was measured high, tried a static regen in local supermarket carpark and it came down from 22g to a "wall" at around 15g measured.

 

I agree that odds are you probably had a fault caused by too many short journeys during lockdown (as many others have found) that may have caused the soot to build up and struggle to clean down.

 

I took my car to a friend's garage who put down some foaming cleanser that he said is better than the liquid that just sits at bottom of DPF, after a few stop/starts and 2,500rpm held while he put cleaner in, the car was put back together and I went for a quick drive to clear exhaust of the foam.  Back to garage and plugged in my VCDS to do a static regeneration, and the soot that was "stuck" at 15g, dropped to under 1g. 

 

Speaking of VCDS, it might be an idea to let on where you are in the Country so you might find someone with VCDS to do an independent scan, and if you like I can ask my friend what product he put in.

Edited 5 October, 20223 yr by varooom
Formatting

I've been in a similar position, as being retired from work and then having lockdown has resulted in my mileage plummeting.  In the year between MOTs to September 2021, I only covered 1,800 miles and in total I've only done 37,000 miles, which only averages just over 6,000 miles per year for a car that's 6 years old.  

 

During lockdown, if I noticed the fans were running when I stopped after a short journey and it was trying to do a DPF regeneration, I'd immediately drive up and down the Brecon bypass 3 or 4 times using sport to keep the revs up and so far it's kept me out of trouble and the warning light has never come on.  Having covered 2 long European trips this summer covering 6,400 miles, this should've given the filter a chance to clean itself!

 

I'd like to swap to a petrol engine and was planning on doing so when the car was 5 years old, but lockdown, the shortage of new cars and the falling vale of my pension pot has meant deferring it for a while.  Apart from any DPF filter concerns, I'm happy with keeping the car for a bit longer and £30 per year car tax gives a useful saving over a newer petrol.

Thanks again for your engagement guys.

@SurreyJohn yes I am ruing the choice of an oil-burner, but who knew in March 2019 what would transpire in the next 3 years?  At the time I was doing 20k+ miles a year on commuting & leisure so it seemed like a good idea....

@varooom your points are good ones (except that @SurreyJohn got it right, I cruise at less than 2,000rpm) that I'll take into account going forward; yes I'd like to know the name of that cleanser product please.  I'm in East Dorset and would be interested in VCDS - my only knowledge of that thing at the moment is how to spell it - I assume there are pointers to VCDS descriptions in this forum somewhere....

 

Anyway, here is the feedback from dealer.  When I came in the first time it showed there were two failed attempts at DPF regen.  They did a forced regen which went through OK and hoped would work but then the emissions light came on again a month later.  They found a fault code relating to the DPF and the technician followed a technical bulletin that involved visually checking the EGR cooler and the DPF.  The EGR looked fine but the DPF showed soot on a part where it should be clean (the soot should pass through and be clean by the time it gets to the part of the unit that they found it still present.)  This demonstrates a failed DPF, maybe a crack or break but being a sealed unit they can't know for sure.  The master technician advised that unfortunately this is the only way to fix this fault.  Even after removal of the DPF there are no further inspections/repairs they can do to resolve this other than a new part.

 

Regardless, I've raised the issue with Skoda UK myself (they had previously declined to make a goodwill contribution when dealer approached them) expressing my surprise and dissatisfaction.  Surely they'd want to know what went wrong with their part?  We'lll see where that goes.

 

Two further kicks in the teeth: (1) the parts are on backorder and may take up to 2 weeks to arrive; maybe they haven't had to replace enough yet to keep a stock in?!  And (2) my car is in bits so I'd incur more costs if I asked them to put it back together for me to use until the parts arrive and/or take elsewhere.  Reluctantly I'm gritting my teeth and sticking with them.

@SurreyJohn It seems I managed to interpret the <2,000rpm wrong (I read that as greater than, so apologies)

 

The cleaning product that got me past the "wall" of the DPF regen not getting below 15g of soot is called JLM DPF cleaner, I am sure some will say snake oil, but after this I could regen the car to under 1g of soot.

 

VCDS is a software platform and a hardware cable to scan and perform coding changes on your car, if you was to buy, then you need HEX-V2 as your car is after 2015 to read all modules

https://www.briskoda.net/forums/topic/262215-list-of-vcds-owners-previously-known-as-vag-com-vcp-owners/

Assuming the dealer is good enough at what they do and is correct about the dpf failing. You should keep trying to get a good will out of them or SUK. Just keep pushing.

Also sounds like you are learning a bit about DPFs so this shouldn't happen again and you'll have many years of happy ownership.

For a bit of info I replaced my oil burner back end of 2020 with a PHEV. With COVID and not having the need to travel to see my parents as they both passed, I didn't need a mile muncher any longer. While I did have it I exclusively used posh fuel and quite often ran it in sport mode when driving round town. Just to keep the revs and heat up.

On 06/10/2022 at 10:48, CaptainDun said:

Surely they'd want to know what went wrong with their part?

Are you serious? - Skoda UK or VAG!!! 😲