DPF Management

Notes

  • Applicable to Euro 4 (with closed-type DPF) and EU 5 gen2 models mostly.
  • Euro 5 gen3 (MY 2012+) and Euro 6 are similar but come with more functionality built in.
  • DPF management code is very big and complicated, tons of states, conditions, timers, delays, safety checks etc. everywhere. Nevertheless I have studied most of the machine code from all four software generations, might add some more stuff for later EU5/6 models in the future…

Description

Note that the chart represents trigger areas, not like going back and forth through all states. Y-axis is EGT at DPF inlet, the most important temperature.

  • Soot accumulation < 65%: Nothing to do. Soot will accumulate or burn off passively depending on exhaust gas temperature (EGT).
    Unfortunately, passive regeneration needs significant sustained engine load to be effective (reduce or maintain soot level)!
    (Personal experience with Euro 4 Impreza using cruise control on motorway: actual (GPS/OBD-II) vehicle speed > 130 km/h, Euro 5+ might be better at this, though.)
  • Soot ≥ 65%: If DPF is warm enough, ECU will turn on active regeneration – commence fuel post injections to actively raise DPF temperature to roughly 650°C. In case DPF being too cold, it defers when possible. Low DPF temperature has one advantage at least: less flow resistance.
  • Soot > 85% and DPF temperature  too low: Soot-high warning also known as vehicle speed request. Turns on DPF light steady: DPF light - steady Ideally when there is enough engine load, EGT and DPF temperature rise to a point where active regeneration can be activated. DPF light may stay ON till soot drops below 75% (hysteresis). If soot further accumulates, state goes into red area, see next item.
  • Soot > 100%compulsory regeneration needed aka dealer visit request: One of several reasons that trigger flashing DPF light Seems like in this state it does not do active regens anymore. Better get to dealership for diagnostics and compulsory regen as soon as possible.
  • Soot > 135%DPF Limp-Home Mode = DTC P1469 or P246C: DPF light flashing: Reduced max power. Compulsory regen not allowed anymore – without applying special tricks the DPF has to be replaced! Subaru might refuse warranty if customer had ignored flashing DPF light for too long.

Active regeneration

ECU seems to keep this going for ~12 to 12.5 minutes, even if soot has dropped to very low percentage already, also continues when idling. Note that the soot value does not necessarily drop to 0%, depends on conditions – how quickly DPF temperature is being raised, engine load (beneficial) vs. coasting (unfavorable) etc.

If engine is turned off while active regen is in progress, it must abort the action. No harm done this way except there’s probably some soot left, next regen will occur sooner and regen counter is not being incremented. Likewise, distance since last regeneration parameter is not being reset to zero. Next time the engine is running, ECU gets to analyse DPF state and decides as usual, AFAIK not really taking any previous regen into account.

Just do not rely on the regen counter for comparisons – short-distance operation will result in very low numbers including high mileage interval values as ECU rarely gets all the time needed to complete the process.

Compulsory regeneration

Done in parking, needs special software (SSM-III, SSM4) that dealerships have, we can do it, too.
On Euro 4 models ECU revs the engine up for 10 minutes (does not wait till all soot is burned off, e.g. may stop at 25% soot), 15 minutes on Euro 5.
Engine speed follows a pre-defined graph, using 2.600 rpm mostly, in order to achieve some engine load due to friction.

Oil dilution

Any active (including compulsory) regenerations cause additional engine oil dilution. See post Oil Dilution Graph.

Euro 4 vs. Euro 5

So far we’ve seen mostly same constants e.g. max soot capacity 26 g in both ROM types, looks like DPF hardware is similar. The reason why Euro 5 usually get significantly larger distances between DPF active regenerations is the result of producing less soot in the first place. This is due to smaller injector holes, higher average fuel pressure plus overall engine refinements. I would assume the downside of smaller injector holes is increased sensitivity regarding fuel quality.

Special Topics

Recorded Values / Statistics

Mileages with DPF light ON and DPF light flashing are being recorded. Flashing light distance > 1.000 km seems to switch into DPF limp-home mode independent of soot level.

Euro 6 adds some advanced parameters for statistics/driving style apart from recording max injection amount, max vehicle speed etc.

Extended compulsory DPF regeneration

Late 2011 dealerships were provided special PAK files, flashable onto Euro 4 & Euro 5 gen2 models, allowing modified compulsory regeneration at workshop. Normally in cases were soot had risen > 135% somehow, logging DTC P1469 DPF limp-home mode, the only official remedy was to replace the expensive DPF because at this level even compulsory regeneration is denied by the ECU. Basically, special ROMs allow soot levels up to 170%. Indicating such peculiar ROM, the DPF light will flash more rapidly like this: . Forced regen also takes a lot longer (45 min vs. 15 min). Whether saving the DPF has worked out (DPF light remains off) or not, this software must be replaced with normal ROM as the temporary software is not suitable for driving.

ECU ROMs for later models (MY 2012+) already have special long mode compulsory regeneration functionality built in. As always, the ECU does the whole job, including the decision which mode to choose, the tester just triggers the operation.

DPF delete

Apart from being illegal almost everywhere, stock ECU firmware does not cope too well with DPF mechanically removed. The software must be adjusted as well to avoid side effects like active regenerations and possibly limp mode later on.

Euro 4 models: ROM code enforces an active regeneration every ~6.500 km, not caring about (fake) sensor values.

Crossing water (creeks)

Since DPF sits down low and gets very hot (> 650°C, 1170°F) during active regeneration, getting in contact with water it may warp due to temperature shock and therefore be destroyed according to Australian forums.

Links

Updates

  • 2017-03 added special topics, minor refinements

104 responses to “DPF Management

  1. Pingback: ('09+) What causes a DPF regeneration? - Page 6 - Subaru Forester Owners Forum

  2. is it possible that somone programms the ecu without dpf functions, because i replaced dpf with normal sport cat, problem i have is the regeneration , it made without dpf.

    thanks

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    • Current status is we know most of the DPF logic. Several DPF configuration switches are known, however, at this point we’re not sure we know everything needed to disable DPF perfectly. DPF logic is really extensive, calcs and checks a lot so one must be careful. We’re certainly close, depends on demand…
      Please use About-webform to contact us, include car model info and ROMID or CID if you have it, English or German.

      Like

      • Hello!

        How is possible to deactivate the DPF logic on a Impreza Europa version mj 2009?
        Is it possible to run an exhaust system without DPF ?
        many thanks in advance

        br

        Gerhard

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      • any update on this has it been done having mine done on 30/05/13 will let you now

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  3. HI Guys,

    I am from South Africa and own an MY10 Outback 2.0D. The quality of our fuel here is somewhat lower than that which you european guys are accustomed to. My DPF is regularly going into a driving request mode (steady DPF light) and even though I am able to get to 60+ km/h for more than 15 minutes mostly, I have now had the dealer visit request 3 times in the last 10k km. I have the Euro 5 version boxer diesel.

    The question I have is as follows, Where can I obtain info on removing/blanking the DPF and reprogramming the DPF logic?

    By the way, thank you very much for an incredibly informative site.

    Regards,

    Christo

    Like

  4. Hi,
    First, many thanks for sharing this information on web!
    1. Do you happen to know at what motorway speed the passive DPF regeneration begins? I have an Euro 5 forester diesel and observe a 10-15 min long active regenerations at approx. 600-800 km intervals. I also observe short (5 min long) active regenerations after a long motorway drives at approx 120km/h in 6th gear, which looks as if the speed or RPM or engine load is too low for passive regen to start.
    2. Is there any possibility to install a DPF soot saturation indicator on dashboard, possibly through an Android phone? Which OBDII interface and software would you suggest? Is it possible to trigger active regeneration?

    Thanks and best regards!

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  5. Can I remove the DPF from my MY 2011 Impreza Diesel? It has to be done in the ecu software or only via hardware?

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  6. Hello, i want to remove Dpf from my impreza , and seeing reply from mathias, i was wondering how to do that ? just replace the mid pipe? And what are the problems with ecu and regeneration?
    Thanks.

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  7. What do you think of welding a straight pipe through dpf? I Have heard of this been done on other cars… (although I haven’t heard any feedback)
    Idea is that soot level never raises and regen not needed.

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  8. Not resetting the “oil dilution counter” on oil change is another reason for DPF light flashing

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  9. Szilárd Kiss

    Hi, anything known about differences between regular and premium diesel, aka v-Power or BP ultimate ?

    Like

  10. Hi there!
    Any updates on DPF “removal” from ECU? I am asking for 2011 OB.
    I have an offer here but I am not sure how successful it might be. For example what’s happening with active regeneration or oil dilution when DPF switches are turned off.

    Like

  11. have you any update on the dpf removal as I am wanting this done forester diesel

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  12. Hello, you can reset the counter of the Impreza diesel particulate filter on 2010 model with open port 1.3 cable. What software you can use

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  13. I have a legacy diesel euro 5. Done 98 km, no garage regens needed to this stage. But at 70km it was overfilled by Subaru and it went into the full limp home mode. Service garage said they had to do 7 forced regens. I notice the comment above that special tricks are needed or a new dpf is needed. What are they? I was suspicious of their actions, they used half a tank of diesel to do it. Now it’s needing forced regens all the time, and its about to go out of warranty.
    Love the car and engine but they really have not sorted this dpf thing. No other diesel car I know of has so many issues!

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  14. Outback Diesel MY10, No DPF issues until first service at a Subaru Dealer at 60K.
    Had previously serviced the vehicle myself every 10K (easy to remember) using the highest available Castrol fully Synthetic oil available (see their website for oil recommendations) and a genuine Subaru Oil Filter.
    You MUST reset the Dilution counter at every service. This can be done by the Owner.
    Following the 60K service special at the Subaru Dealer, by coincidence or otherwise, I have had ongoing DPF issues ever since.
    Typically the vehicle will not travel more than 5k – 6k after a “workshop forced regeneration” before the DPF warning light illuminates and goes into “Limp Home Mode”.
    My personal diagnosis as an old Fitter & Turner Tradesman, is that the DPF is “not sufficiently engineered for the purpose for which it was built”.
    In other words, The DPF cannot perform Diesel Particle Filtration under Australian “Normal driving conditions” burning commonly available Diesel, without blocking up or causing issues on a regular basis.
    The limp home mode also causes the loss of: Cruse Control, Hill start Assist, and acceleration power in the upper RPM’s.
    An owner should be able to expect that a vehicle will operate as it was “Designed to Do” without the need for “Specialist Mechanical intervention” when driven and serviced as per the manufacturers recommendations for the lifetime of the vehicle or until components either “wear out” or are due for “service-life replacement by a specialist mechanic” as one would need for a timing belt replacement for example.
    The fact that these DPF’s are not functioning correctly for their expected life-cycle is clear proof that either the DPF itself or the supporting “network of functions” are “not Engineered for the purpose for which they were built.”
    I will conclude by saying that the Subaru Outback Diesel is a great reliable engine, easy to service, plenty of room to work around the engine bay, is a comfortable, well designed spacious vehicle and is a pleasure to drive.
    The Subaru engineering team need to “Re-engineer” the DPF system so that it will operate trouble free for the lifetime of the vehicle which I would expect to be in the order of 700K or 20 -25 years.
    At present, Forced Regenerations every 5k – 6k is most unreasonable !!!!

    Like

    • Hi David,
      I am also having issues with Forester diesel approx. 83600kms of varied driving, but too much city driving. The last download from the ECU from Subaru showed the regen happening at around 200-300 KM apart. I have higher fuel usage since last reset by Subaru 3 months ago. Have you suffered similar situation. Currently my Forester is in with Subaru for assessment after the engine died 4 weeks ago. suggestions of over revving the engine?

      Like

    • Outback Diesel MY10, DPF rectification update.
      It has been 18 months since my last post (March 14 2014) and I would like to share the results found and a method of rectifying the DPF issue once and for all.
      My Outback has 123k on the clock and from 120k commenced (misfiring). The symptoms were in the form of a jerking action upon acceleration and was more prominent when the engine was cold.
      The cause was that two of the four injectors had failed and were not operating correctly.
      An investigation found that these early DENSO injectors were failing even as early as 50k as reported by owners.
      I personally wrote to DENSO Australia to ask if they would come to party with replacement of my prematurely failed injectors and was very quickly “brushed off”.
      The 16613AA030 DENSO injectors are NOW produced with DLC coating on the critical wear areas.
      DLC stands for Diamond Like Coating and is a surface hardening process to extend the serviceability of these injectors.
      The DPF will continue to fail if excessive soot is constantly being pumped into it regardless of the quality of the DPF element structure or any other factor.
      This can be quickly diagnosed by fitting a straight through exhaust pipe in place of the DPF, and monitoring the amount of soot produced under normal driving conditions.
      Note: you will need to bypass the pressure differential sensor by joining the two small rubber hoses from the sensor together.
      The exhaust should be clean and unnoticeable with the exception of a heavy acceleration burst. If the exhaust is black soot under normal driving conditions, then you will need to have this rectified first.
      In my case, as I would also suspect with many early Diesel Subaru’s, the exhaust was black soot caused by the faulty injectors.
      These have been replaced with later version (DLC) injectors. you will also need to read and write the new injector codes to the ECU after replacement.
      Secondly, extending the life of the new injectors.
      Neither Subaru nor DENSO would provide me with the Diesel filtration grading, yet Subaru Dealerships are quick to blame “poor quality diesel” for ALL the DPF issues, which the diesel filter plays a major part in protecting and providing clean fuel to all the fuel components.
      I have fitted a Catipillar 1R-0749 Diesel filter as a Final Filter after the OEM DENSO filter.
      These Catipillar filters are in my opinion the best that money can buy and at $20.00ea are a very cheap high quality 2-4 micron filter that will not only extend the life of the injectors (see http://www.catfiltercrossreference.com/assets/data-sheets/English/ComponentProtection-FuelInjectorTest.pdf ).
      This was done quite simply by connecting the outlet of the OEM filter into the inlet of the Catipillar filter and connecting the outlet of the Catipillar filter to where the OEM outlet was originally connected.

      Ensuring the DPF is trouble free.
      1.First ensure that the engine is operating clean with no visible soot, (see above).
      2.If your DPF is Beyond Regeneration or Serviceability as mine was (only 6k after a new DPF was fitted, still with the faulty injectors that the dealership had not diagnosed) then:-
      Remove the DPF and fabricate a one piece jig that neatly bolts to both end flanges in order to ensure exact realignment and positioning of both flanges as original.
      3: Remove one end of the DPF by cutting through the welded seam with a narrow grinding blade, remove the end furthermost away from the Turbo charger, this is the end that continues to the rear of the vehicle.
      4. Carefully clean out (remove) all the silicone filter membrane, this is approximately 200mm deep until the metallic membrane of the Catalistic converter is fully visible.
      5. Fasten the DPF assembly into the Jig for alignment ready for welding. There should only be a 3mm gap between the body of the DPF and the end flange.
      6. Re-weld the DPF assembly and finish off by coating it with Hi-temperature spray paint.
      7. Re-assemble into the vehicle, read and clear all DTC (dealer trouble codes).
      8.Write to the ECU that a new DPF is fitted to enable the ECU to re-calibrate associated parameters.
      9.Start the engine and check operation.
      I have not had any issues since.!!
      This will provide a much greater reliable vehicle, Save on dealer forced DPF regenerations, Save on fuel that is consumed during normal operation DPF cleans and provide a much better fuel consumption.

      I trust that the above information has been of practical benefit to all Subaru Diesel owners.

      Like

      • Trevor Budden

        Gday, i am wanting to cut the dpf filter out of our 2010 Subaru Outback as i have had enough of the constant warning lights even after a manual burn. It is becoming unreliable even on long drives as we constantly need to complete regular manual burns to get the warning lights to go out for short periods of time. Do you have any advice on whether cutting the filters out of the dpf is a long term solution to this problem?

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      • Hi,
        mechanically removing the DPF is not a perfect solution, people have been doing this for years, you’ll find international forums on this topic. ECU will still do a regeneration every now and then, albeit at longer mileage intervals. Might cause limp mode. ECU then needs special reset command.
        AFAIK no one has developed a 100% firmware dpf-delete patch yet. I am almost sure I could do it but it’ll be serious elaborate work, therefore expensive. Reducing price by selling the solution to multiple customers over time is too risky – ROM would be copied easily – I know this business too well.

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    • This happens to my 2010 outback. Love the car and the drive but the dpf is not designed for city driving anywhere in the world!!

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  15. David,
    I agree 100%. My 2012 Forester Diesel motor with just over 50 000 ks is giving particulate problems [I spent the day today going to and from the workshop because of the flashing light problem] and the service manager tells me the problem is that the car is being driven too much in town! I suspect out of town driving for anyone living in a city, in my case Johannesburg, is a small percentage of the total drive undertaken. But, whingeing over, is there something one can do to prevent this problem, without removing the filter? Should I let the motor warm up before driving off? I have just done a 7 000 kilometre trip [over December/January] around the whole of Western Southern Africa in this car with a full load and experienced no problems whatsoever. Wonderful car. Back at home it starts behaving like a sissie. Is there anything to be done?
    Gordon

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  16. Outback Diesel My11 had no DPF issues until 75,000 kms. The light came on, I drove at 110 kph for almost an hour. the light still did not go out and went into limp mode. Took it to the dealer and they replaced the filter. The car has not yet done 85,000 kms, but has been back to the dealer 3 times because the light keeps coming on and sometimes goes into limp mode. All the dealer seems to be able to do is remove the codes. They have a number of Outbacks with the same problem but admit they don’t know haw to fix the problem. Unfortunate because otherwise it is a good car. Most of my driving is open road in outback Australia. How do you reset the Dilution counter? Does anyone know how to fix the problem?

    Like

    • Oil dilution reset procedure is in the cars manual. It works.
      Reading data on DPF’s in general they have a lifespan of 80k-140k km. (UK RAC.)
      Yes, short drives, low speed/power or under 20min are not enough to heat up DPF to burn soot. Should not buy any new diesel if that is your requirements.
      Good quality C3 oil is essential.

      Like

    • Hi Andrew, have a dealer found a solution for your Problem. My Outback Diesel My 11 has the same mistake. The Problem is that the particular rate is rising very fast and I think the Problem could be the injector or leaky air in the intake System.

      Like

  17. Gents I have a 2010 Outback Diesel just over 175000 Kms, up until I found what I am told was a dirty tank of diesel I have had no problems at all with this fantastic car, at the moment we are 3/4 through a holiday around outback Australia and now heading home with the DPF light flashing and the engine management light, stability, and park warning brake lights aglow on the dash. I have not seen a Subaru dealer that looks like they know how to fix the light problems and the people I have spoken to along the way suggest best to deal with a dealer you know. Yesterday the DPF caused them plastic sump cover to catch fire which was fun but today full steam ahead, touch wood, and heading home, no limp mode yet and we will look at that if it raises its head.

    Steve, June 23rd 2014

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  18. I wonder if the problem is so recurring, why doesn’t Subaru gives proper directives to its dealers to solve it? Or, as David correctly suggested that maybe the whole DPF saga is because of a combination of lot of factors.
    I have a second hand Legacy 09 clocking at 115K kilometres and I got this flashing DPF light yesterday. A quick “googling” yielded the same issue over and over again.
    My question to you lot: How much does it cost to get the issue sorted out at the minimum? Since I am out of warranty, I would like to know how much this is going to cost every now and then?

    Thank you!

    Like

    • I Have a Subaru Outback Diesel euro 5 year 2015 and at 50km I begun to have the DPF lights on ,etc went to the dealer 7 times for the same reason, the 6th time, dealer did an upgrade of the software and Wash the DPF ,the 7th time they finally change the DPF for a new one. as I know it has to be change every 40-70 km depends on your luck.

      so I’m asking for an extended warranty just for the DPF, it is expensive I’m not expecting to change it at my cost. I try to changed for a gasoline outback didn’ t work.

      Like

  19. Hello friends! My 2010 Legacy diesel, euro5 makes active regens (no ligt signal) every 100km urban and every 250 km highway. This seems too often to me. I am right? If yes, what can cause such problem, consider I use only original oil and good quality diesel? Car is 155.000 km. right now. Huge thanks for every opinion in advance!

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  20. Hello to all, my 2010 Legacy diesel, euro 5 makes active regeneration’s every 100km urban and every 200-250 highway (I drive on 4th gear until it fully regenerates with the needed rpm’s around 2300-2500). No light is flashing, but still noticeable power loss and etc. I use original subaru’s motul boxer diesel oil and good quality diesel fuel. Is it normal to regenerate that often? If no, please share opinions about possible reasons. Huge thanks in advance!

    Like

    • Hi, I only really know my Euro 4 diesel and it is about the same or even worse than your car is doing. Technically however, Euro 5 should be significantly better and I remember having read forum threads somewhere confirming this.
      Passive regeneration needs sustained high exhaust temperature – demands a good engine load for longer periods. Even on motorway I only got high mileage (above 400 km) between regens when driving at roughly 140 km/h with cruise control ON – above allowed speed limit and only possible during night due to traffic. At lower speeds I only got distances like 150 km.
      Basically, regeneration depends a lot on conditions and driving style. By watching live data logging – exhaust temperatures – I was able to improve regen behaviour and distances a little bit.
      I recommend searching & asking in forums, comparing results with actual Euro 5 users.

      Like

  21. Thank you for your answer. This was useful. I will join some new forums. I even think about removing it, if no other solution occurs.

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  22. I have done small research related to DPF and periods on mine EURO5. The result is, that the distance between ends of two subsequent regenerations can be 80 km or higher (see picture on this forum http://goo.gl/tak66T). The distance depends on many factors like: driving style, urban/suburban/highway and in my case mainly on ambient temperature. Lower the temperature – longer distance between regenerations. I found that there is no relation to oil (OMV/Motul) or fuel maker (OMV/Shell/Agip/…).

    There is nice article related to our engine, but it is in Czech (http://goo.gl/GWU2ru).

    Like

  23. Mko, thank you a lot. So it appears distances in my case are normal. (tanks GOOGLE for translator) articles were very useful! I also noticed difference between winter and summer DPF regeneration’s. I will use some of Bardahl’s additives for DPF cleaning and etc, to make distances between regeneration’s longer. I will post info, when I have some experience. Thanks again!

    Like

  24. Good day All

    I am a service manager at Subaru in Johannesburg South AFrica. I have driving many Subaru Boxer diesels and have had lots of kilometers travelled. i am convinced that i have the true understanding of the DPF .The light will only come on when we do stop start driving. This means you start up the engine and driving for a five or 10mins and then switch off and restart after a few hours. The soot accumalated on the cold start is left to stick to the exh system and it gets hard due to the low exh temperature. the soot will only melt off when the exhuast (exh) temperature is raised to over 400degrees cellcius. So my suggestion is that we should not use the car for short trips only if we are going to be travelling for more then 20mins at a time and also take note that sitting in bumper to bumer traffic or engaging the higher gear at low RPM does not block up the DPF. I drove my last outback with a CVT transmission and that car would go to the 4 gear at 40km\h .Enjoy the subaru diesel.

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  25. Hi All, I purchased my Diesel Outback only 3 years ago, has about 150,000kms on it. I have continual problems with the DPF and once again have taken to dealer to fix yesterday. We got the call today – a new DPF is $6000 AU or thereabouts and the card can’t be fixed without it. Not happy to say the least. This was not an issue that was explained to me when I bought the vehicle, and if I had been made aware of this at the time, I would not have bought this version as all I do is short trips. The mechanics keep telling me this is why we are having this issue all the time.

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  26. A new DPF should not cost anything like $6,000 AU. I had one replaced for less than $1,000.

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    • Hi Andrew,

      Where did you get the replacement DPF? I think mine is on continuous burn as the fuel consumption has jumped up,

      don

      Like

    • Really that’s nice to know where abouts was that I’m afread of hearing those words that I may need to replace that part ?
      I also have the glow relay cercuit failure code coming up 1380 which I’m afraid they are going to say needs replacing its bullshit they have made these cars to have parts they have a tiny life span and a huge price to replace with apparently such how any justify this crap!!!

      Like

      • HI Michael, we didn’t end up replacing the DPF. My husband loaded the car with a big trailer, loaded the trailer and took the car for a really long hot drive to burn out the buildup. Probably not necessarily the way Subaru would do it, but it certainly cleared the issue. We then took the car to our subaru specialist mechanic as the warning lights on the dash would not clear even though the particulate buildup was gone. As it turned out the car had to go into Subaru to have an update done on the computer, as it was the computer that wasn’t recognising the issue had been cleared. We haven’t had a problem since and the light has not come on again since (4 months). Mind you, I am driving longer distances more frequently now, so the car does get at least two long runs a week.

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  27. GOOD AFTERNOON. I have to agree that the diesel does not like to be started up and switched off after short while.
    i have been driving many Subaru diesels and had never had the DPF issue. i drive in bumper to bumper traffic.

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  28. Hi All. in South Africa the price of a new Dpf is 60 000.00 rands which converts to about 6 000.00 us dollars.
    But the Dpf does not need to be replaced ever. If the soot soot level is so high that the car wont even rev up then we remove the DPF from the car and then remove all the sensors and the heats shields around it and then let it lay on a pile of burning wood for a few hours.
    this a i sure method of melting down the soot in the DPF.
    i have done it and it works guaranteed

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  29. G’day Gents,

    I’ve been having exactly the same issues as above and have found some interesting stuff along the way. I currently have a 2010 Forrester Diesel with 55k on the clock. What I’ve experienced in the past regarding the DPF light coming on was on 2 separate occasions it was attributed to a loose hose on the inter-cooler (right side looking into the engine bay).I also noticed a fluctuation in my AC flow corresponding with my throttle position and a hissing noise coming from under the bonnet. The third time I had an issue is why my forester is still in the shop. When the light came on again and I heard the hissing noise I popped the bonnet when I got home expecting to find the same culprit but this time is was the hose between the inter-cooler and turbo. It had actually perished and split and disconnected from the turbo altogether. The turbo was completely covered in oil and was dripping off the plastic good for nothing bash plate. I took it into my usual Subaru dealer to fix the next day. They had it all day and then at 3pm that afternoon told my they didn’t have the replacement part but did a full service on it in the mean time. Mixed emotions for me at this point. I work away so booked my vehicle into for another time to replace the hose. When I returned to replace the hose they now tell me my DPF is completely buggered and looking at a replacement cost of around 6k. Word of warning here is that this is a lease vehicle and I actually payed for and extended warranty but because the DPF is classed as a “filter” its not covered. And because the hose is classed as “non mechanical” its also not covered (replacement cost $550). I actually believe the hose has had a split in it for some time as my performance and more so fuel efficiency doesn’t seem as good as it used to be. My personal opinion is that with the split in the hose the efficiency of the turbo and subsequent effectiveness of the DPF filter have been well below par but not enough to set off the DPF alarm and once it finally split it created unrepairable damage. On a somewhat positive note I have been told by another Subaru dealer here in Perth Western Australia that they get their DPF filters repaired locally by a company called “Global Heat Transfer” for a cost of $1600. I know its a bitter pill to swallow but $1600 is much better than $6000. I would like to finish by stating that despite the latest issues with my Forester it has otherwise been a dream to drive and the overall quality of the vehicle is excellent.

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  30. First timer on this site. Some engineering comments. The DPF must work like a catalytic converter, perhaps without the platinum group metals. Might just be a plain ceramic matrix to catch then cook off the carbon. The prices quoted seem impossibly high for a replacement filter. Regenerating a DPF surely cannot be a difficult thing. Need heat and excess oxygen. I would use an oxy acetylene blowtorch set to oxidize and heat the innards (DPF removed from car) up to 600 celsius at least. Thats a good red glow. More is better. orange is up near 750 celsius. Otherwise, a blacksmith furnace will heat the entire DPF to orange. Hope they are made from stainless.

    Have played with carbon fibre cloth and a blowtorch. It certainly ‘evaporates’ when heated to orange. If I had a soobie diesel I would also investigate heat wrapping the exhaust to preserve exhaust temp up to the DPF. My two cents worth, given I’m looking at buying a diesel soobie. MK

    Like

  31. Pingback: Neuer Rußpartikelfilter voll nach nicht mal 1 Jahr! Seite 2 : Ölverdünnung durch Diesel im Motoröl. Das passiert, wenn man v...

  32. I have had an interesting (to me anyway) behavious in my MY10 Euro4 Forester in that when the car is warming up, after perhaps 2 kilometers of driving the engine will emit a howl. Its a long drawn out “oooooooow” which starts at about 50 kph, and only stops once the car is warm (beyond perhaps 8 kilometers). It will remain silent for the rest of the day.It is not the airfilter assembly, but I thought it could be related to the EGR warm up of the DPF? Could I be correct? Am I the only one with this howling?

    Like

    • Hi, never heard about such an intermittend howl. Does it occur regularly? I recommend data logging (RomRaider, cheap K-Line interface will do for Euro4).
      DPF active regeneration should not begin when both the engine and DPF are still cold, there is no howl anyway during a regen.
      EGR valve is definitely related to warmup. At cold start, EGR is closed in order to warm up cat & DPF, also causes more knocking sound. After a few km (soft) driving, EGR valve opens (like in normal operation for low demand), engine sound gets noticably softer. This is an immediate change however.

      Like

  33. Good day Mr Langeveld

    I think I know what the cause is of the noise.
    its a whistle from the turbo pipes in the induction or perhaps a leaking turbo gasket.
    when it warms up completely the pipes are then sealing properly. I have had it before.
    not serious but should be attended to at the next service
    Ismail Subaru Johannesburg. Service manager

    Like

  34. Can anyone help me understand where the SAR (Soot Accumulation Ratio) is derived from? I’d guess pressure, but I have a recently purchased MY10 Outback, that has had the DPF removed (I didn’t know), but is desperately trying to do a regen, thus spraying lots of fuel out the exhaust pipe…. sigh.

    My guess pressure differential would have to be zero, when the filter blocks are removed – so that shouldn’t be a factor.

    Thanks to the awesome information on this site and the forester site – I actually managed to piece together what the problem was with the car (using Torque Pro).

    Am I looking at a super dodgy DPF delete (no software changes), or a reasonable one with some software changes, but maybe a faulty sensor?

    Thanks

    Like

    • Evan Lamberton

      I have exactly the same problem. Did you find a solution?

      Like

      • Yes, I reprogrammed the computer and turned the DPF regen off. The solution so far has done about 4000ks, no issues. I guess I should start selling this solution.

        Like

  35. Hi again, Subdiesel!

    As you know, I have own Subaru Forester 2017 EuroVI since February. It already have 10.000km, but I’m a bit worried because it does the regens each 200-250km most of the times, and I think it should be more kilometers. My trips are mostly on highway, with some dense traffic. My Oil dilution is between 4.6-5.2% of diesel and almost all the regens are complete.

    Thank you so much!

    Like

    • Hi!
      200-250 km between regenerations is low indeed considering Euro 5/6 models. Does not necessarily mean that there’s a problem. Perhaps DPF algorithms do not serve your particular driving conditions well. Feel free to email logged data files for analysis.

      Like

    • Hi, I have my15 forester D cvt euro6. I am trying to get info using torque custom pid and BT dongle (a chip one currenttly). I can’t get any info other than simple & standard info like speed rpm coolant Temp. … which kind of equipment you use to get the info on euro6?
      Thanks!

      Like

    • Hi Kutavyz,
      How are you going with your issue? I’m having the same issue with my OB MY15 Euro VI. My driving is mostly highway with some heavy traffic as well. I do about 70km a day on average most days, with probably 60% of it on highway.

      I have been monitoring the oil dilution and DPF values extensively in Torque and having it analysed by Subdiesel, but it just seems everything is working fairly well, other than the soot level going up too quick for passive regeneration to burn off.
      My oil dilution actually often hits 10% and triggers the DPF warning to flash… going back to the dealership tomorrow for the 9th time in the last 16 months.

      Like

  36. Find a garage that use BG PRODUCTS and you will have no problem with your DPF, these products will also improve economy and performance, they really do work.

    Like

  37. Hi all, I have a 2013 Diesel Outback with on going DPF problems for over 2 years. Every website I go onto has the same info about problem DPF’s. I am fighting with the Subaru Dealer about not advising me of the DPF requirements. Has anyone tried to fight Subaru about the problem?

    Like

    • yes me! I have an Outback 2015 Subaru euro 5 and I started Having DPF problems on August 2016 still under Warranty but wont be after 100,000km now is 58,000km so after going to the dealer 7 times, this last time finally they changed DPF for a new one (they try not to do it because is expensive) but I try to have my car change for a Gasoline one didn’t work Subaru is not assuming that cost. so I ask for an extended Warranty until 200,000 km on the DPF two days ago so they are thinking about it. because the problems is that DPF last 10,000 to 70,000km depends on your luck I guess. I’m in Santiago Chile South America by the way. The Dealer is talking to Subaru ( I call to Subaru directly but they say for solving problem they contact only throught the dealer),

      Like

      • Hola! Im from Chile also, rancagua. Looking for a diesel forester for a dpf delete. Have you info about it?

        Like

      • Nicolas, I had the same problem as you did, I’m from Santiago Chile in August 2016 they finally change the DPF
        in (Indumotora One) my dealer, and also ask for an extended warrant, wich I got until 150,000 km nothing more.
        Subaru did not want to change my car (I ask for that at the begining).

        best regards

        Paulette Pefaur

        Like

  38. I have a 2015 CVT diesel Forester and currently fighting Subaru with this issue. I started having issues when the waste gate solenoid failed and got replaced under warranty a few months ago. I am now getting large plumes of smoke from take off at lights, at low speed, at high speed, anytime really! Also a smell blowing into the cabin from time to time that smells like melting plastic. I am now seeing daily smoke issues with about 100km between instances, yet Subaru tell me that this is still ‘normal’. They have fitted a rear facing dashcam this week to try and capture footage as the smoke is excessive and not blue, but more white/light grey.

    The amount of completed burn offs to attempted is very low and i do mixed city and urban driving with approx 500km per week traveled.

    Really at my wits end with this and not sure what else I can do.

    Like

  39. Forester XT 2011, last month DPF came on figured it was due to short distance drives red lining everywhere, took it to dealer and naturally en route on the duel carriage way it switched off so the dealership looked at me like wtf, ran a forced regen and gave it a full service, apart from my window not going down automatically all was well.

    One month on DPF came on flashing and noticed serious lag with the turbo, it would spool up then drop out around 2500rpm then kick back in again.
    Got it to my work went about my day went to leave and it wouldn’t start, called RAC who ran a battery check all was OK but recommended getting a new battery as it was 5 years old, then ran forced regen flushed a load out but wouldn’t drop below 33% and DPF light was still flashing.

    Took it for a blast home and still having the lag problem and light still on, could it be battery, turbo on its way out or just need to take a sledgehammer to the DPF?
    Any help would be greatly appreciated as I need my BOOST back!, 😥

    Like

    • ECU should have logged trouble code (DTC) at least. If you don’t have diagnostic interface and software, readout is standard procedure at dealership. Possibly a limp mode. As always data logging is highly recommended.

      Like

  40. the dpf light only comes on and stays steady when the percentage is under 100%. red lining the engine is not advisable but it did help clean out the soot and that is why the light went off. the diagnostic machine will not be able to tell why the light was on because the fault does not get memorized. only when the engine light comes on the system will memorise the fault code.

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  41. I purchased a CVT diesel Forester 2016 D-L in July this year. From Monday to Friday I drive to work and this consists of 10mins of 80km/hr then straight onto the highway for 20mins going 100-110km/hr (this 30 mins is non-stop driving). I take the reverse route on the way home and at most it’s 3x week bumper to bumper traffic for the first 15 mins going home – due to peak hour highway traffic. On the weekends I do short trips to the shops and out etc. In the last 4 months the DFP light has come one 3 times flashing, it never illuminates to signal to do a burn off, just goes straight to flashing. The first time it came on flashing after 2 months of having the car and has since come on every month in October and now this month November. Subaru requested that I keep a log of my driving history and activity (km’s travelled, traffic conditions, time travelled) since the first time the DPF started flashing. After one month of keeping this log and driving, the DPF light started flashing a second time (never illuminates) they reviewed my log and came back and said that I need to drive it for longer?! So I took this on board and once a week I started driving it on the highway in manual mode for distances between 40-60km at speeds between 90-110km as well as always keeping revs between 2500-3500. So after a month I thought I was in the clear and then the DPF light started flashing again last week (not illuminating again). I kept a second log incase this happened again and report was submitted to Subaru and once again they are saying I’m not driving it enough. Called the customer service for Subaru immediately to escalate my case and they got my details but probably wont get back to be for another few days. I believe there’s something faulty going on with the DPF system because I’m driving it in the recommended conditions EVERYDAY. The manual states that to initiate a burn off when the DPF illuminates (mine never illuminates) is to drive it above 60km/hr between 1500-2500 revs and for more than 15 mins. I am fulfilling these requirements. At my wits end right now.

    Like

    • Hi! Diesel cars fitted with DPF are not that sensitive to driving style, sounds like a cheap excuse. Even very short trips are fine as long as you go beyond let’s say 20 minutes every now and then so engine + DPF can heat up and perform a regeneration, burning off captured soot. And steady DPF light would come on first, too.
      There must be something else, could also be a software glitch.
      Did they ever tell you the trouble code (DTC)?
      Flashing DPF light is caused by 4 reasons, see post DPF light.
      Engine control unit data logging would most likely help in diagnosing the problem, either invest in own equipment (OBD device + Torque app for example as many users do) or dealership might provide Subaru driving recorder device. Feel free to send any data you can get for analysis.

      Like

      • Thanks Subdiesel for your comment. Subaru Australia have gotten back to me today and after reviewing my log and driving activity they are once again saying the same thing: ‘your driving activity isn’t suited to a diesel car’. They even mentioned that 30 mins of highway driving is not sufficient one way as it takes atleast 15 mins to heat up the car and then another 15mins for the regeneration to take place. So essentially they are saying as soon as my car is about to start regeneration I get to my destination and turn my car off. This builds up soot and increases oil dilution which doesn’t let the car register that the filter is full hence why the light goes into flash mode and never illuminates solid, she said something a long those lines.
        They are also now shifting the blame back onto the dealership that sold me the vehicle saying they should have done the proper ‘prequalification’ check to properly determine that my driving habits were suited to a diesel vehicle – and in this instance it isn’t. I have contacted my dealer today and they say my driving habits are suited and they think there’s a fault with the DPF system in my car. So the dealership is now shifting blame back onto Subaru. The salesman that sold me the car has been great but he said from here, all I can do now is escalate the issue and put everything I know in writing to my dealership’s General Manager. Not really sure what he can do but I guess I’ll be exhausting all options before I can start taking more action. I’m going to pick up the car from the service centre tomorrow and request all the reports and diagnostics that have been sent to Subaru.

        Are you able to elaborate on the OBD device and Torque app to someone that knows nothing about them, and also how I go about getting it and using it? Thanks!

        Like

      • Can’t provide a tutorial but check out page Extended OBD-II. Check out some links and search keywords from there, you should be able to find some guidance and ready-to-use config files for Torque Pro app on various Subaru forums.
        As has been successful in several cases, long term data logging will provide hints what’s wrong. I doubt it’s just driving style. Personally, I’ve had many partial =cancelled regenerations due to short distance driving, never got a problem, not even soot warning once. Highest estimated oil dilution was about 6 %.

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      • Hi Subdiesel. My DPF light has gone straight to flashing on two occasions i.e. no steady light. Do you know why this might happen? The first time I took it in the DPF was 192% blocked and the second time 123%. These two events happened within a month of each other (about 3000km travelled).

        Like

      • Sorry, too little information to make an educated guess.
        How many miles did you continue to drive after the DPF light came on? 192% soot is a lot…
        Any readout of DTCs and ECU parameters?
        Euro 5 model, I guess? Latest software?

        Like

      • I did about 10km after the light started flashing. It went into limp mode and was towed in. I think it is Euro 5, could be 6. I don’t have any other readings sorry.

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      • Sorry it is a 2015 Outback.

        Like

  42. ismail desai service manager subaru johannesburg south africa

    good day all. I have been following the discussion closely. I am of the opinion that the problem lies with the short trips on the weekend. I too use to drive only 33 kilometers in bumper to bumper traffic which would take up to 1.5hrs and never had the DPF light flash on me. However if I drove my car for six kilometers and then parked her off for a few hours. the next time I drove her I would get the DFP light to come on and sometimes even just go straight to flashing.
    I am the service manager at a Subaru dealership in south Africa and we are experiencing the same issues with my clients. the wife would use the car to drop off the kids at school and do the nearby shopping and the DPF becomes a problem. try not to use the car for short distances and less then 15 mins trips and you will find the car behaves itself.
    enjoy the Subaru diesel.

    Like

  43. Just a comment; in the process of removing the reprogramming the computer and removing the DPF filter, I can contradict what they are saying about the regeneration cycle initiation. Just a quick recap – [2010 Gen 5 Outback] I bought a car with the DPF removed and no reprogramming done. When I finally figured out what the problem (why James Bond style exhaust plume out back of car) was; I tweaked the torque app and got the Regen ‘On’ light up. To verify what I was doing, I could travel 700m around a suburban block (that is; 4 corners, from cold) and the car would be going for a regen and there would be diesel spraying out the back.
    I hope this helps.

    Like

  44. Hi, Subdiesel.

    I wanna ask you if you know if the oil dilution calculation takes more variables apart from estimated fuel evaporation. I ask you this because since the last oil change, oil dilution takes too much time to low down with the same driving conditions as before. For example, usually, when I do a trip of 190 miles/305 kilometers, oil dilution decreases 0.2 or 0.3%, but now, it barely decreases a 0.1% or nothing. This is causing that after 932mi/1500 km after the oil change, oil dilution is already at 1.9%.

    I have a MY16 Forester with 19500mi/31500km. I’ve never seen the DPF light because I try to finish all the regens and my count is 105 attempts and 90 completed.

    Thank you very much 😉

    Like

  45. We have a early 2010 Outback diesel in South Australia, travelled 142,000km.
    Bought new, we told the dealer how we would use it & no warnings were issued. We did 800km round trips once a month and 50 or 120km each way trips most weekends. But workday trips to work or shops was only 1km. We have seen the DPF light glowing many times. It usually settled by going for a 20km drive out of town 80kph in 3rd gear then 110kph in 4th. Highway driving we enjoyed going 110kph at 1800rpm in 6th gear, now we know it wasn’t such a great idea.
    But the last 2 years it has needed several dealer regen burns. Once while climbing the expressway at 100kph in 5th gear the idiot light went straight to flashing without the usual steady glow. Now the dealer tells me the DPF has 52% ash that can’t be cleared and the idiot light will show itself more often. They have warned me a replacement DPF will cost A$6,000 or $7,000 !
    I drive it in 3rd gear at speed limits up to 80, 4th gear up to 100kph, never use 6th gear now. But 1st gear is too high a ratio !
    It’s a nice car in many ways, but the DPF system needs a lot of improvement !
    Do people in Australia have suggestions ? I have sent an enquiry to BG products as recommended by someone here.

    Like

    • Hi David,

      Some thoughts;

      1. Was it all Subaru Services? Could a non – low-ash oil have been used?
      2. DPFs can be washed out; but I don’t know the ash estimation algorithm to see if that needs to be reset after a wash.
      3. My DPF was removed when I bought it (unknowingly), and I then turned it off in software; Car runs fine, however, if you mistreat it, it can leave massive black smoke clouds behind the car. It probably needs a substantial de-tune, like the later model series.

      Cheers

      Martin

      Like

  46. Looks like we are fighting a losing battle with Subaru and the DPFs. I live in SA and the “cleanest” diesel we have is 10ppm. I am not sure what Europe or Australia or the rest of the world has, probably ZERO PPM. I have a 2014 Outback diesel and it has been back twice in one month (about 3000km) for a forced regeneration. I doubt that there are many people in the world who do the “ideal driving” required for the DPF not to give problems. We all drive in traffic. I love the car and I bought it for its reliability and performance and at the moment I am getting neither. I don’t think I will be buying another Subaru. I know the petrol variants don’t have this problem but I love diesel.

    Like

  47. ismail desai service manager subaru johannesburg south africa

    hi there . I am also sa. I suggest you contact me and maybe I can be of some help. I work for Subaru Johannesburg.

    Like

  48. I own Forester MY15 diesel. Almost 1 year monitoring with torque. Oil Dilution 10 or 11 % triggers dpf warning. It happened to be because after oil change they have not reset oil Dilution through the obd port with the special subaru application on PC.
    Concerning regen frequency, just before going to ask for reset – at 10% dil- and in summer, it was every 60 or 70 km! It strongly depends on external temperature. Last winter at 0 Celsius I drove 800km without regen, even partial! In summer, every 80 or 100 km it starts, and I see soot growing quite fast up to 64-66%, then it starts. In winter it grows very slowly.

    Like

  49. I have a 2013 Subaru Outback CVT Diesel, the manual has Steps for resetting Onboard Data after an oil change for a manual car, but not CVT Auto. Any assistance appreciated

    Like

    • There’s no difference between MT and AT models as far as engine oil change & oil dilution reset is concerned. Oil dilution is ECU internal, AFAIK not shared with other control units etc. Just try the procedure, see if it matches Engine Oil Change. Btw., can you email me a scan or pic of the manual page describing the reset procedure?

      Like

  50. I’ve sent 2 photos of the Owners Manual instructions to your email ( had trouble pasting them to here)

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  51. Hi, thanks for feedback. Today I’ve confirmed the correct procedure for resetting the DFP management . And it worked! So for an automatic CVT the process is the same as for manual. (A) transmission in park (B) park brake on(C) start engine(D) apply foot brake (E)rear defogger on (F) park lights on (G) rear defogger off (H) park lights off (I) rear defogger on (J) park lights on(K)rear defogger off (L) park lights off(M) release foot brake …
    On instrument panel when successfully reset the “glow light” (depicted as a yellow coil . Will illuminate for several seconds , confirmed RESET!

    Like

  52. Hi subdiesel, we have had a problematic 2010 Subaru Forester S-3 (EE20Z Engine). Came in September 2016 with blocked DPF, we also noted that the plenum chamber, inlet manifolds & EGR cooler had excessive carbon/soot build up. We specialize in cleaning manifolds, intercoolers etc, so we removed & chemically cleaned all components. We also reversed flushed the DPF to zero soot saturation & full flow through DPF. Initially the car drove for approximately 2000 k/lm before the DPF light came back on. Again soot saturation was very high so we did a forced regeneration, oil & filter change & oil dilution reset. About 1500 k/lm the vehicle came back with same issues. Now after looking at this & having also replaced the DPF with an aftermarket new DPF & fitted a new differential pressure sensor the problem is getting worse by the minute. My son is our diagnostic technician & has looked at all avenues including oscilloscope patterns for injectors etc. Yesterday we completed another forced regeneration but this time blocked off the hoses to the pressure sensor as per directive from Subaru Australia. The regeneration completed & got the DPF back to zero soot saturation. I drove the vehicle last night home which is 36 k/lm away. Initially the power on tack off was brilliant. Most of the trip home was on express way at 110 k/lm. When I came off the express way I noticed heavy white/grey smoke coming out of the exhaust every time I stopped & then took off from traffic lights etc. My son came home & hooked up the scan tool after the vehicle had been sitting for about 30 minutes & found no irregularities. Same thing happened again this morning when I drove the vehicle to work. There was no smoke what so ever when I started the engine cold, nor when I drove through local roads stop/starting. No smoke that I could see on the express way all the way in. But heavy smoke again the moment I got off the express way, stopped at traffic lights & then took off again, so much so that all traffic behind be backed off because of the smoke. We work on many common rail diesels with great success but this one is certainly testing us. Any information or advise would be greatly appreciated.

    Like

    • Hi! I have a 2017 Forester with the new Euro6 diesel engine. My regeneration distances are about 350km in winter with a lot of bumper to bumper traffic on the highway, but no city driving. In summer it fluctuates a lot, 150/200…
      The white smoke when you accelerate from a stop usually happens when the car is doing an active regeneration. I think that this behavior is normal during an active regeneration.

      Like

    • Hi,
      This does not sound right – excessive soot, heavy smoke… Never seen such a thing on a DPF car personally.
      Perhaps faulty injector(s) produce excessive soot, too much for the DPF system. Unfortunately, AFAIK, on Euro 4/5 models, engine must be taken out in order to replace injectors.
      Another common cause for unreasonable soot and DPF trouble is an intake air leak (to and from intercooler), you probably checked already.
      Have you got any ECU data readout? Injector patterns sound interesting. Feel free to send any data through email.

      Like

  53. Hi Subdiesel, we have seen many 2010 Forester’s with a mass of carbon/soot built up in the plenum chamber, inlet manifold & EGR heat exchanger/cooler. A large majority of it is from excessive amounts of oil entering the intake system via the engine breather etc. Combines with unburnt exhaust gases & forms solid matter in the air intake components. This particular Subaru is behaving oddly in the fact that it is trying to do a regeneration after only 40 k/lm. Will try to forward diagnostic data in due course, thanks.

    Like

  54. I have had an issue with 2011 Forester DPF. I had a regen done by a licenced Subaru mechanic. Then after a week of the light going solid again then flashing with many other warning lights I took the car to a Subaru dealership. They picked up a split air inlet and then said that all data for the DPF had been cleared by the previous mechanic and that I would need to buy a new DPF (at considerable cost $4k fitted). The bit about clearing the data requiring a new DPF is what I cant understand. I would assume that resetting any counters would be something programmable and likely set counters to zero anyhow. What are they saying – that they cant work on the old DPF for some reason or is this a scare tactic. Cheers John

    Like

    • Hi, what had been the cause for the compulsory regen in the first place? Solid or flashing DPF light? Did the mechanic tell diagnostic trouble codes? Cracks in inlet piping are quite common unfortunately, causing DPF troubles.
      In dealership software (SSM) there are functions for reading out DPF data, saving as small binary file, and also restoring this data to ECU. This must be done when replacing the ECU. There’s also a DPF reset, telling the ECU that a brand new DPF has been fitted. If your mechanic did this by accident, it was his fault and probably all DPF data is lost. However, as this data is basically statistics, helping to estimate when to replace the DPF, it’s not super important. Your car should run fine, active regen performance might be degraded a tiny bit but perhaps you won’t notice it.
      For example, ECU tracks fuel flow and based on this it slowly increments estimated ash amount over time. Ash cannot be burned off so the ECU firmware calculates decreased soot capacity, affecting the regen process a bit. DPF regen counter is also useful statistics and again, the software might do something slightly different based on it. Aforementioned DPF replacement procedure resets all these values in the ECU. AFAIK there is no automatic backup. There could be some traces in ECU memory (RAM) though. I would need you to get an OBD interface ($30+) and connect to the car in order to investigate.
      Now, (arbitrary) ECU values can also be set manually using diagnostic protocols, at least I can. Just to mention it, if you had any recordings (printout, data files), these or reasonable values could be restored.
      To summarize, first of all, in case DPF data had been cleared, it’s not your fault. Secondly, having you to pay for expensive DPF replacement is not justified at all in my opinion. Apart from doing nothing, a much cheaper option would be to get the current filter cleaned or if you like, perhaps replace it with a newer, used and cleaned, DPF. Btw., I know a guy who even got a Euro 6 DPF fitted on his Euro 4 car and regen performance is great since then.

      Like

  55. Thanks for the – very reassuring reply. I managed to purloin the readout the Subaru dealer provided and the figures indicated prior to the second regen (forced – flashing icon and fault code P2463) ODR 7%, soot at 139% and ash at 0%. The car has done 110k and prior to the split inlet piping had never had any issues at all (lots of highway distances). A week later and before replacing the inlet pipes the car performed about 6 complete active regens (solid icon) in 6 days before the DPF icon started flashing again. This time, at the Subaru dealer their concern was the 0% ash. From my reading it seems that one needs to do a lot of kilometres before the ash levels even get to 10%. It was this reading that the Subaru dealer claimed had been zeroed by the previous mechanic and so the DPF filter needed to be replaced to allow a reset of the baseline. When I discovered this I was a little dubious about the claims and felt that since the car had been performing so well until the inlet pipes split that perhaps 0% ash might not have been too far from the truth. Unfortunately the previous receipt with regen didn’t record the levels. I will follow up on your suggestion of getting an OBD connector. I will also see if prior mechanic kept a record of values somewhere else.

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  56. I left a message earlier in this thread about my Forester going straight to flashing light status and then into limp mode on two occasions. I also often read about guys saying that their cars were busy with a regen and I didn’t know what they meant. Other guys advised that if your car was busy with a regen you shouldn’t switch it off. I have since sold my Forester and bought an Audi A4 TDi and every now and then the revs go up for a while, especially on downhills. I assume that my car is doing a regen when this happens? My Scooby never did this so maybe that was my problem. Subaru here in SA weren’t very helpful and wouldn’t look to see if my car was doing its own regens and that forced me to sell it. They just said it was my driving patterns. I am very sad to leave the Subaru family after owning three, but I lost confidence in them. Didn’t expect that from Subaru.

    Like

    • good morning Mr Coetzer. sorry to hear you were forced to sell your subaru. the Audi pushing the revs up on a down hill is not related to the regeneration. it has to do with the transmission. regeneration on a subaru would make the engine knock sound louder and while driving you would notice the boost is low when accelerating

      Like

  57. DPF Permanent Trouble Free Rectification Fix.
    It has been 18 months and 30,000 kilometers since carrying out the DPF modification detailed in my last post of Sep-29 2015.
    I can confirm that since the “Upgrade” as detailed in that Post, My 2010 Diesel Outback is performing “Better than New”.
    The fuel consumption has decreased and now provides an average of 800 kilometers / 60L, which is up from the previous 730 kilometers / mixed city – highway driving previously recorded.
    There has been NO DPF issues whatsoever and No regeneration’s, forced or otherwise required.
    Since the “upgrade” there has been no recorded DTC’s. (Dealer Trouble Codes).
    The engine oil is also noticeably cleaner between oil changes which are done at 10,000K intervals.
    The engine operates considerably smoother with a faster reaction time when accelerating and towing loads.
    The “rectification fix” has also facilitated “true engine monitoring” through the visual observation of the exhaust gas which remains clear during normal cruising and upon acceleration. This was “NOT Possible” prior to the upgrade as the DPF masks / hides visual indicators of a poor running engine.

    This Fix is a long term corrective solution to DPF problematic issues.

    Like

    • Hola David.!!

      I want to do the same “upgrade” same time i buy the 2015 diesel forester im looking for. could you give me more.info about how you did it?
      Schnyder1@hotmail is my adress.

      Best regards
      Nicolas

      Like

  58. Can you re-post the fix please

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    • Frank,
      I have personally dealt with the same symptoms that you have described in your posts and many of the posts in this forum.
      If you scroll from the beginning of this forum down to the first “David Grima” post, the fix is listed in detail there.
      If you require any further information, please do not hesitate to contact me at: DJE.Grima@hotmail.com.
      It is a sure fix with no side effects or need for re-programming the ECU.
      The ECU remains “as built” and the vehicle is now consistently reliable, greater economy and more power.
      Sincere regards,
      David Grima.

      Like

  59. Hadnagy Tivadar

    hello guys, My dpf regeneration number is 999 , what do you think It can go the counting forward?

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    • If I understand correctly you are concerned about special number 999? Don’t worry, maximum possible value is 65535 because this variable is stored and transmitted as 16 bits (unsigned int16 in programming jargon). For computers, anything like 999… or 1000… is nothing special at all. See Wikipedia: Integer (computer science)

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      • Hadnagy Tivadar

        okay, thank you very much. Yesterday I sent you an email, I write it here too, maybe you can help me

        I Have a subaru impreza 2009 diesel with euro4 motor, now I had changed the motor to an euro5 model with 26000km on it. It run without problems 6000km, than I changed the oil to Q8 brand 5w40 (changed the filters too), now my dpf led is kepp lighting steady, soot acumulation is 52%. If I make a 30 minutes trip the light is going off but after restarting the engine the light came up again. What do you think? I downloaded the rom raider to make a log file to analys, what parameter should I log from which you can tell me something?

        I very appreciate your helping.

        Sorry for my bad english 🙂

        Have a nice day,
        Tivadar from Hungary.

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      • I’ve received your email, will get back to you this weekend.

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