P245900 dpf regeneration frequency

[Tdimrtwo]

I have a 2015 GSW with 180k miles, never did anything to the emissions system besides adding adblue. CEL and p2459 code a few days ago. I cleared the code, but it came back today, so I’m guessing it’s time to clean/replace dpf or do the Malone delete. Is this correct? Anyone have success cleaning their DPF, or should I just bite the bullet and replace it? To me, I can’t really complain since I’ve gotten over 180k trouble-free miles, and I’ve seen threads from folks with multiple dpf replacements before 100k.

 

[ticaf]

What is your ash level?

 

[Tdimrtwo]

Don’t know, I’ve never looked at that. I’ll hook up my xtool D8 and see if I can read it. Otherwise, I guess I’ll have to upgrade my vcds to cover 2015 tdi. Is there another way to read ash?

 

[oilhammer]

Assuming the differential pressure sensor is good, and there are no leaks, you may indeed be up against a DPF replacement. Sadly, bunches of these that were perfectly fine get tossed in the scrapper due to the silly added (unnecessary) phase of the Gen3 Dieselgate nonsense.

Couple things I'd do:

Get to the hoses for the G450 and G505 pressure sensors on top of the engine, the ones on a bracket under a little space blanket. Carefully remove the little hoses that go to them, and with compressed air, blow back down the tubes, to make sure they are clear. Also make sure there is no soot up in them, and that the sensors' nipples inside where the hoses connect are clean. If there is a buildup of soot or moisture in them, they cannot get the correct reading. One is for the EGR, one is for the DPF, but they both share the one tube.

If that all looks good and clean and secure, then you can initiate a manual regen provided the ash load is not too much. Not sure what the threshold is on the CRUA, but it won't allow one past a certain amount. This does a super powerful regen that can sometimes overcome a DPF that is not performing as well as it should due to a variety of things, but often driving conditions. You may not fall into that, though. This is for folks who let the engine idle more than necessary and do lots of short trips with sometimes interrupted/incompleted regens.

The DPF itself is a big deal, as it is well over a grand and it is labor intensive to replace. It could be around $3k to have it done.

 

[Tdimrtwo]

Here are the relevant values that I found with my code reader, I’m not sure if they’re good or bad.

60article filter, time since last regeneration 2337 s

61article filter, oil ash volume 0.17 L

62article filter, soot mass calculated 6.36 g

63article filter, soot mass measured 5.12 g

64: Particle filter, kilometers since last regeneration 22391 m

67:Mean injection quantity. 5.38 mg/stroke

Can anyone help me understand what these values mean?

 

[ticaf]

Try to get the oil ash mass in g.
You need vcds, possibly OBD eleven to read those values and possibly start a service regen.

And of course, as Oilhammer suggested, make sure the pressure sensors are not faulty (doubtful)

Have you had the VW emission fix on the car?

 

[Tdimrtwo]

Yes, It was a stop sale that I bought new in 2017, so the emission fix was already done. Not sure if the ash number being reported is really in L. Under the dpf regen menu, it reports as follows:

Actual measured value of putty quality of particulate filter (l/g): 0.17

This is the same numerical value, but shows different units. Also, don’t know what “putty” refers to. I suspect l/g is the correct unit, but I can’t be positive. What would a typical ash load value be? I’ll look at my old ALH vcds and see if I installed the upgrade for crua. I investigated the upgrade when I first got the car, but I don’t remember if I actually bought it. My code reader has a special function to start a service regen cycle, so maybe that’s my next step.

 

[ticaf]

I believe the oil ash mass limit is 80g.
So by looking at your oil ash mass, you will know if your dpf is toast.
Something else could also cause the engine to produce too much soot, hence the high frequency regen. A proper scan will let you know that

 

[Tdimrtwo]

Are these the values that I should be watching?

62: Particle soot mass calculated 9.67 g
63: Particle soot mass measured 17.12 g

 

[ticaf]

ASH not soot

 

[Tdimrtwo]

Ok, thanks. So please tell me if I’ve got this straight:
1. During normal engine operation, soot is produced and is collected in the dpf
2. When the soot mass reaches a certain level a dpf regeneration cycle is triggered and diesel is injected into the dpf to burn off the accumulated soot.
3. When the soot burns off. but leaves behind a small amount of ash, which can’t be automatically removed.
4. When enough ash accumulates, the dpf becomes contaminated, and must be manually cleaned or replaced to restore proper operation. This level can be monitored with the oil THG ash level in the dpf.

 

[Lightflyer1]

Sounds correct. Except these dpf's aren't made for cleaning. Some have tried it though I think. They would have to be cut open and rewelded shut when done.

 

[740GLE]

also when driving on the highway soot can be burnt at the same rate as accumulated, under what's known as "passive regens"