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DPF issue help - P2458

Discussion in 'Leon Mk3 (2012-2020)' started by ciaranmcw, Feb 28, 2020.

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  1. ciaranmcw

    ciaranmcw Active Member

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    Have a 64 reg 184 FR and the a DPF warning came up last week. Did a 15/20 minute drive at 3500/4000rpm on the motorway to try clear it it, no change though.

    Plugged in the carista and got this error back -
    P2458 – Diesel Particulate Filter Regeneration Duration


    Connected the play store VAG DPF app and got these results, but I'm not really sure what I'm looking at.
    [​IMG]



    Was quoted by some companies for 199£ for a full clean.

    Is that what this needs most likely

    Any opinions are appreciated! :)
     
  2. Legojon

    Legojon I only wanted a remap
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    If I recall correctly from using the app. Driving on the motorway won't trigger a regeneration. It'll happen when that bar reaches the right hand side. The filter doesn't look in a particularly bad state, although they do have a finite life. Is that 105,000k correct? Personally, I'd wait for that bar to get to 100%. Make sure I complete the next regeneration. If it fails, maybe look at the DPF and exhaust sensors first.
     
  3. ciaranmcw

    ciaranmcw Active Member

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    Thank you for the reply.
    Ya 105,000 km.

    I'll be driving tomorrow for an hour or so so I'll see does it change then.
     
  4. ciaranmcw

    ciaranmcw Active Member

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    Got bar to 100% and nothing. Now sitting at 105%.
    Going to garage to take a look on Monday and prob get it cleaned.
    Went into limp mode twice in the 100mile trip.

    [​IMG]
     
  5. Legojon

    Legojon I only wanted a remap
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    Yeah, looks like it's not able to regenerate. Hopefully just one of the sensors.
     
  6. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    VAG DPF is so useful for this sort of thing.

    As has been said, the car won't usually regen until the bar get's closer to 100% (usually about 22 to 23g of soot mass is the trigger point).

    Having said that, the red `timer` icon at 70% means that it wants to regen and is waiting for the right time to do it. Would suggest a possible incomplete regen before.

    The really scary figure is the regen duration. 210 minutes or over 3 hours. That should read zero when a regen is complete and during a regen it can take 10- 20 mins depending on whether you are motorway or town/stop-start driving. During a regen this counts up and resets to zero when regen is complete. For some reason, your car has been trying to complete a regen for nearly 4 hours. That's not right.

    The good news - your oil ash residue is only 32%. That's good. That's the leftover soot from a DPF burn that sits in the DPF. When that gets close to 100% your DPF needs changing/cleaning. Yours is fine. DO NOT pay for a DPF clean.

    You are now at 100%+5% and the regen is deffo due!

    Your car can only regen if certain criteria are met:

    • Coolant temp
    • Various other sensors are happy
    • Over 1/4 tank fuel (sometimes overlooked)
    • Low oil (not sure if this is factual or `worth checking`)

    There are also other factors that influence the regen activation.

    I found this all out when I had my engine carbon cleaned. Got the full diagnostics and an explaination about common DPF issues. Your car won't regen if certain parameters are not met and you'll end up with the DPF light on again. The car wants to regen but can't. A lot of people then pay a lot of £££'s to have a DPF clean, when VAG DPF clearly shows that your is ok in terms of ash residue but it does need to complete a regen.

    I was told that a lot of things (including those above) stop the car doing a regen. So a sticky thermostat stops the car getting up to temp, it won't regen, or the MAF sensor (I think) or a temp sensor is wonky (i.e coolant), the car won't regen.

    As well as the diagnostics, shed loads of DPF help, I also got a full carbon clean and it only cost £100 (and he comes to your house). If your car has faults he won't do the clean but will tell you what to do to sort it out and then come back and do the clean. Best £100 I ever spent on my car.

    Your car wants to regen but can't and something is stopping it.

    What to do? Check fault codes and get someone who knows what they are doing to check the other `what stops a regen` factors. Some you can probably do yourself.

    I've got screenshots of a healthy `proper` DPF regen using VAG DPF. I'll try to post some up.

    *EDIT* On-line search brings up these potential causes of your fault code
    • Defective DPF
    • Defective exhaust gas temperature sensors and/or related wiring
    • Defective exhaust backpressure sensors and/or related wiring
    • Excessive oil consumption
    • Over fuelling conditions as the result of leaking injectors or excessive fuel pressure
    • Corrupted or defective software that affects injection timing and injector pulse widths
    • Defective catalytic converter(s)
    • Defective reductant injection system
    • Failed or failing PCM, but note that this a rare event, and the fault must therefore be sought elsewhere before any control module is replaced
     
    #6 Brian Gordon-Stables, Feb 29, 2020
    Last edited: Feb 29, 2020
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  7. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    So - hopefully these will be in order and I'll try to explain:

    DPF bar gets to 100% (c.23g soot) in this case it's 100%+3%, so due a regen. Red timer tells me it will regen when conditions are met. Regen duration is zero (not started yet).

    [​IMG]
     
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  8. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Regen starts - DPF image turns red, DPF input gas heats up to c.550 to 600 degrees and the DPF regen timer starts ticking (in this screenshot that is already at 2 minutes).

    [​IMG]
     
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  9. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    During the regen the regen duration counter counts up and the soot mass value and slider bar reduce.

    DPF temp in and out values are around 600 degrees.

    In the top right hand corner, the purple negative value is the soot burn rate. The higher the value the quicker it burns the soot off. This is usually between -2000 and -5000 mg/mi. I have found that driving like you stole it does not increase the burn rate!

    [​IMG]
     
    #9 Brian Gordon-Stables, Feb 29, 2020
    Last edited: Mar 1, 2020
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  10. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Here, the regen is nearly complete.

    18 minutes have elapsed. This was in city traffic and took longer than it would on the open road. If the DPF can't heat up through driving revs and speed, the car idles @ 1000rpm and squirts some fuel into your oil. You can usually smell it as well.

    Current burn rate is -5101 mg/mi, soot mass is 6.88g and slider bar is now at 30%.

    [​IMG]
     
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  11. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Last one.

    Regen complete.

    DPF air flow turns green again
    Soot mass is about 5g, slider bar about 23% (it never actually gets to zero)
    Regen duration resets to zero
    Time since regen resets and starts counting again (1 min in this screenshot)
    Distance since last regen resets and starts counting again (1 mile in this screenshot)
    DPF temps start to drop (they'll drop down to about 200)

    Your car is not doing this and you need to find out why.

    [​IMG]
     
    Legojon likes this.
  12. ciaranmcw

    ciaranmcw Active Member

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    That is fantastic, thank you for all that information!
    One thing I didn't realize was the lack of Diesel, I am defo below 1/4 a tank, going to go get some now in hope!
     
  13. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    No problem. This forum has really helped me out quite recently with a blocked heater matrix.

    You can keep your VAG DPF runnning as you drive so you'll know when it starts (or tries to start a regen).

    If having more fuel won't work, try searching for fault codes and/or checking coolant temp etc. Something seems to be preventing the regen but it could be one thing or several. Hopefully nothing too expensive!

    Let us know how you get on.
     
  14. Mr Pig

    Mr Pig Active Member

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    What great information. Thank you for posting this.
     
  15. MATT RILEY

    MATT RILEY Oil burner

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    Looking at the above mate your differential pressure sender is reading 1, presumably this was taken with engine running? Have a look at the other guys pressures and these are what your ECU is needing to see. Looks like you need to look at this first

    Hope this helps.
     
  16. SteveGSXR600K1

    SteveGSXR600K1 Active Member

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    Nice info Brian!
    I does my nut when a DPF issue gets posted (mainly on the Facebook MK3 Leon page) and they all suggest going for a blast on the motorway, in 4th gear, etc.
    Not sure if I missed it above, but there can also be DPF issues if you've interrupted the regen too many times in a row. Probably not the case in this example as he'd done a 100 mile trip.

    There's a chap on Facebook called 'Diesel Doctor Mobile Diesel & DPF Specialist', and it's quite interesting to read his fixes, as 9/10 DPF issues are due to another fault like a sensor, etc. People usually go to him after spending £100's/£1000's on a new DPF and the problem reoccurring a few weeks later.

    Something you may be able to help me with if you don't mind. When mine's doing a regen, if I happen to be stationary (arrived at home) and go to the front of the car, I can hear a noticeable but not quite worrying ticking/clicking noise that is only there during the regen. When VAG DPF shows it's finished and you hear the engine note change (even though it's still at 1000 RPM) it stops. I can only think that it's the post injectors. I'm assuming these are additional injectors to spray diesel into the DPF, Could you hear if yours does the ticking when you next have a regen going on?

    Appreciate the help if you've got the time!
     
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  17. Brian Gordon-Stables

    Brian Gordon-Stables Active Member

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    Hi Steve,

    Thanks for the feedback. Much appreciated.

    As you quite rightly say, taking the car for a blast after your DPF light comes on will usually clear it, but it depends what caused it in the first place. If your car regens properly, the light shouldn't come on at all. If it does, it could be lots of short journeys and it's just unable to complete a regen (happened to my mates Octavia estate recently - less journeys over Xmas). A quick blast did clear it but I've told him that the DPF light coming on regularly is not a good thing. It's only happended once and think it is a one off though.

    For some people, they just don't suit a diesel with a DPF. Too many short journeys and ultimately the car can't/won't regen properly. They should stick to petrol.

    I would agree that interrupted regens could cause the OP's issue but like you say, he seems to have been on a decent run without clearing it. A healthy car should regen. I know he said he had less that 1/4 tank of fuel but probably not for 700km.

    My Mr Carbon Clean said exactly what your DPF guy said - most DPF issues are caused by faulty sensor/A.N other issues and people get sold the dream and pay silly money to have their DPF cleaned, only to have the same issue a few weeks later as the faulty sensor hasn't been fixed. That's why £100 is a small price to pay to work out the root cause.

    As per @MATT RILEY comment, the differential pressure could be part of the problem but I know nothing about that so can't comment.

    In terms of your question Steve, I'm not sure! Is it a 600 degrees everything is really hot type `pinking` or actually a physical clicking noise? I have to say that I've never listened that closely. Next time it does a regen I'll have a listen. What year/model is your car?

    I'm certainly not an expert on this. I'm repeating a lot of information from various forums, Capt. Carbon Clean and my own DPF experiences.
     
    #17 Brian Gordon-Stables, Mar 2, 2020
    Last edited: Mar 2, 2020
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  18. KXL

    KXL KXL

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    I thought a passive highway regen requires 2-2500 rpms and not the 3-4k rpms? Perhaps also give it some when accelerating? I remember old pre-DPF diesels when you did this, a puff of black smoke exits!
     
  19. SteveGSXR600K1

    SteveGSXR600K1 Active Member

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    The sound is a physical clicking. I wasn't after a fix, even though that would be nice if something is wrong!, it was just to see if yourself or anyone can hear a similar noise during a regen.

    I think I've got a video of it somewhere that I was going to show my SEAT service manager, but he wasn't interested...…..
     
  20. 94 RAH

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    You mentioned limp mode? If you have EML light on your DPF will not regen, had this with my 150 fr, faulty exhaust gas temp sensor threw up EML and was due a regen around the same time, naturally it tried to regen before I had the sensor fixed which threw up the DPF light and wouldn't start a regen until the problem was sorted.
    Hope you find your fault, like everyone said it's likely a sensor somewhere!
     

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