I have a   2019  Superb 2.0 tdi with 97k miles on the clock.

When new the car carried out active regens every 250 miles or so. As the mileage has crept up it is now doing regens around the 62 mile mark.

I have had the dpf removed and professionally cleaned. The ecu was reset after replacement to read zero ash etc. 

The regens are still taking place the the same 62 mile frequency.

There are no fault codes and the car runs fine.

The dpf pressure is around 8 mbar after a regen at idle and around 70 mbar at 2500 pm.

These figures seen ok ish and were  far higher before the dpf was washed out.

The egr cooler and differential pressure were replaced last year for a different issue that was rectified. 

I am at a total loss what to try next as the dpf flow doesn't seem bad at all.

No idea what's causing such frequent regens now.

Thanks for any help in advance. 

Edited 25 September, 20241 yr by Jon_67

Hi. I feel your pain. I'm experiencing the same thing with a CRLB engine, 2016 plate 2.0 diesel. Mines every 40 miles though and regularly lose power at high speeds during the regen, dropping to 50/60 mph and then bounces back to normal when the regen has finished. I've done all kinds of things to resolve it but with no codes I've been struggling for over a year now to sort it. Happy to share what I've done but nothings fixed it yet, although some things helped for a while.

I experience no loss of power or poor running symptoms on mine. Runs like a new car even with the frequent regen issue.

I think mine is the dfga with adblue.

Luckily I've not had any issues with the adblue system yet. (Use Wynns adblue additive to try and help prevent crystallisation).

Could replace the dpt with a second hand one for around £350 offf ebay but the pressure figures tend to suggest its reasonably ok.

everything has some lifespan and many things go wrong even before.

frequent dpf regens might be caused by age/wear of filter itself (many miles, city driving), bad injectors (many miles, low quaility fuel), leak in the system.

if the filter is full due to bad injector(s), you need to replace all of those.

there is nothing such like cleaning the filter or using a second hand (=same condition) one.

if there was any liquid used during the cleaning of dpf, its capacity was significantly reduced.

diesel injector can be [very] bad despite you put it on testing and they gave you protocol from test bench that all values are in spec (own experience) and the car was driving very well whole time.

also there is nothing such like used/2nd hand injector or refurbished one. only official bosch injector exchange is worth of it (or a brand new one).

 

6 hours ago, dilino said:

everything has some lifespan and many things go wrong even before.

frequent dpf regens might be caused by age/wear of filter itself (many miles, city driving), bad injectors (many miles, low quaility fuel), leak in the system.

if the filter is full due to bad injector(s), you need to replace all of those.

there is nothing such like cleaning the filter or using a second hand (=same condition) one.

if there was any liquid used during the cleaning of dpf, its capacity was significantly reduced.

diesel injector can be [very] bad despite you put it on testing and they gave you protocol from test bench that all values are in spec (own experience) and the car was driving very well whole time.

also there is nothing such like used/2nd hand injector or refurbished one. only official bosch injector exchange is worth of it (or a brand new one).

 

I experience no loss of power or poor running symptoms on mine. Runs like a new car even with the frequent regen issue.

I think mine is the dfga with adblue.

Luckily I've not had any issues with the adblue system yet. (Use Wynns adblue additive to try and help prevent crystallisation).

Could replace the dpf with a second hand one for around £350 offf ebay but the pressure figures tend to suggest its reasonably ok.

The car has currently done 31 miles since a regen and the dpf differential pressure at idle is 9 mbar. This seems fine and doesn't suggest a partially blocked dpf. Even if the capacity was reduced i would expect it to be higher if there was a ln issue. 

Edited 26 September, 20241 yr by Jon_67

£2740 for a new dpf from Skoda and that doesn't include fitting. Think I'll pass on that one!

Did you check pressure sensors with pressure gauge?

No, haven't checked the two i have. The one one now was brand new. It reads zero when engine off and seems to have reasonably accurate readings as fat as o can see without properly testing it.

Might put the old one back on and adapt it.

It wasn't faulty when I took it off several months ago.  It turned out to be a blocked egr cooler that was causing a previous P2002 code fault. 

Strangely it lasted 105 miles today before initiating a regen.

The previous 2 regens after the dpf was removed and cleaned occurred after 62  miles. Same town driving habits, no long runs that would cause the extra miles between regens. 

Will see how it goes. Possibly the first 2 regens after cleaning removed some more soot or loosened cleaning deposits.

Edited 26 September, 20241 yr by Jon_67

 A blocked EGR cooler can lead to improper combustion, resulting in increased soot production. This excess soot can overwhelm the DPF, causing it to clog more quickly

 

A malfunctioning EGR cooler can cause temperature fluctuations in the exhaust system, which can affect the regeneration process of the DPF

 

All these DPF issues started with this EGR issue ?

 

 

 

The egr cooler was replaced 20k miles ago at 77k miles  after P2002 code kept popping up .Seems ok at the moment as there is no return of the code.

 

45 minutes ago, Jon_67 said:

. Same town driving habits, no long runs that would cause the extra miles between regens. 

 

 

Can you describe your typical driving? Or is this quite typical? If so then high mileage but all town is likely the issue. Longer runs are needed to clear things out.

Is it all possible that the dog wasn't actually cleaned correctly and is still somewhat blocked? If still blocked but the car thinks it's not (due to coding) then you could see the behaviour you have.

Hopefully it was cleaned correctly.  Had it done by fuel Injection Services in Burscough near Southport.  They seem quite reputable having been established a long time. Used them before but i have thought about how clean the dpf actually is now after cleaning.. 

They have a specialised machine on site to do it and check the flow rate after. 

I suspect driving around for a couple of hundred miles since I got it back and 3 regens have removed some more from the dpf as the dpf pressures have dropped even more and the distance between regens have gone up from 62 for the first two afer cleaning to 10t miles for the third.

That I can live with as the previous 62 mile intervals before and just after cleaning were ruining the fuel consumption. 

Thanks for your help.

Edited 26 September, 20241 yr by Jon_67

The idle pressure reading after a regen seems reasonable but the one at 2.5K rpm seems very high, I cant be sure until I have checked mine again or looked for the sheet of paper where I recorded previous tests but my gut feeling is that it is high for a DPF that has just been regenned.

Hi there any luck with sorting out the issue ?