DPF Regenerations, Driving me mad!

**Lewis-Oddie** · 01-07-2016,02:31 PM

Afternoon all,

I collected my 2.0 TDI Ultra S Tronic Black Edition in March and have to say that so far, it's been fantastic. Love the car but one thing that's starting to drive me mad is the frequency and intrusiveness of the DPF filter regeneration cycles. I suspect there may be a fault with the car because it's running through regeneration cycles up to three times a week! Admittedly I don't do a lot of motorway driving, it's mainly town driving but I do occasionally drive on motorways.

Here's why I think I have a fault. On Saturday and Sunday of last week I went up and down the M60 to Warrington (About 30 miles from my house) on both days. I would assume that at some point during these journeys it's been able to complete a regeneration cycle?

On Monday morning I went out to the car and began my journey to work only to find that the car decided to try and do a regeneration within minutes of starting the journey! What drives me insane is that when it's in the process of doing a regen the car feels a little bit more harsh to drive. The gear changes are a bit more snatchier than usual, has anybody else experienced this?

Thoughts please, ta

**robes401** · 01-07-2016,02:40 PM

It does seem as though the regens occur at pre-defined intervals rather than necessarily making the most of motorway journeys. I don't notice the car being more harsh during regen (but maybe I'm not so perceptive!) but it does idle quicker and disables start-stop and the fans continue for a prolonged period when parked. I'd be interested to know what the parameters are that define time for a regen...

**Lewis-Oddie** · 01-07-2016,02:44 PM

Thanks for the reply bud. Yes I can definitely tell when it's part way through a regen cycle. As you say, the tell tale sign is the idle speed sits at around 1,000RPM. The change definitely isn't as smooth in my car, that's what frustrates me the most I think.

**pany** · 01-07-2016,06:19 PM

A colleague and myself were just talking today about how loud and often the regen runs. We both do lots of motorway miles, and even after 4 hours straight at motorway speeds, we've both stopped to find a regen underway and the fans running like crazy. Seems to be a VAG 2.0 litre thing as a colleagues VW GTD is similar.

**Dave fitch** · 01-07-2016,06:35 PM

I wrote a post about the very same thing when I did a little review after 1,000 miles.
I am now at 6,000 miles and the regen is much less frequent but as you say not when you expect it, IE on a longer run, but usually quite soon after starting out and yes usually when it is a shorter run (as though it seems to know lol) if I can I usually try to take the car back out for another ten minutes to allow the regen to complete. I used this method for five years with my previous BMW and had no issues.
I would make the point that just because the fan is running when you stop doesn't seem to always indicate a regen you can usually smell the exhaust when it is regenerating.
To recap yes mine is exactly the same and I have been assured that this is all perfectly normal.

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**JamesMo** · 02-07-2016,09:24 AM

The new 'Ultra' engine based on the EA288 family seems to regen much more often than the old EA189 I had in the previous A6. It appears that the ea288 has a more complex set of rules for the regens and according to the service training documentation for the new engine, there is a 'mileage regen' that triggers every 465 miles if there hasn't been a successful regen. This happens regardless of the DPF filter load and is designed to keep the soot loading in the DPF low thus prolonging its life. This I believe is why you can get the regen happening even at the end of a long motorway run (which would typically burn the soot off as you drive) if the mileage timing is such. Hope this helps clarify what people are seeing happen.

**stuart** · 02-07-2016,09:36 AM

I don't think that it is mileage or time based, the DPF will regenerate when the soot level reaches a set level, so if you do a motorway trip there is no guarantee that it will do a regeneration, may not have enough soot...

My 2015 Skoda Superb seems to do it a lot more than the Seat Exeo I had before it, the Superb does it every couple of weeks, but it is only used at weekends, so around every 250-300 miles, I usually pull up at home, the rev;s are high so, as I live n the country and the main road in national speed limit just go about 4 miles at higher revs and all is back to normal...

It was in for a service a couple of weeks ago so I asked a mate who works there to check the DPF soot content which at the time he said was 15% and look to be regenerating normal...

I suspect that the setting now are more stricter or better calibrated than a few years back so they seem to do it more...

**JamesMo** · 02-07-2016,12:30 PM

Originally Posted by stuart

I don't think that it is mileage or time based, the DPF will regenerate when the soot level reaches a set level, so if you do a motorway trip there is no guarantee that it will do a regeneration, may not have enough soot...

My 2015 Skoda Superb seems to do it a lot more than the Seat Exeo I had before it, the Superb does it every couple of weeks, but it is only used at weekends, so around every 250-300 miles, I usually pull up at home, the rev;s are high so, as I live n the country and the main road in national speed limit just go about 4 miles at higher revs and all is back to normal...

It was in for a service a couple of weeks ago so I asked a mate who works there to check the DPF soot content which at the time he said was 15% and look to be regenerating normal...

I suspect that the setting now are more stricter or better calibrated than a few years back so they seem to do it more...

Sorry if I was unclear, there are of course 'normal' DPF regens - according to the documentation there are 4 possible regen modes,

Passive - where regen happens as you drive - eg long motorway drives, no increased exhaust temperature is required as the soot burns as you drive
Active - where the ECU causes the regen to happen, this is triggered by DPF soot load, ECU adjusts fueling etc to force temp up in exhaust and regen to happen
Regen trip by customer - where the DPF light comes on the owner needs to take the car for a regen drive, driven by soot load and inability to reduce (regen is not completing), again ECU controls the fueling to increase exhaust temp and force the soot to burn off
Dealer regen - DPF light and workshop message - needs a forced regen at the dealer. Drinking in last chance saloon.....

On top of these options, there is now a mileage based regen that happens at 465 miles if no regen has happened i.e. long motorway journey where the passive regen has been happening as you've driven.

I believe they have done a lot of work to improve the longevity of the DPF filters obviously keeping the soot load as low as possible is key to improving their life.

Hope this clarifies - if you google 'EA288 engine' you can find the service training document that contains the full detail (I have the link but i'm not sure if i'm allowed to post it due to copyright)

Cheers