DPF REgen Freq P2459 2013 TDI Passat

[jhort]

Recently performed DPF cleaning at shop to see if it would alleviate symptoms. Shop puts DPF in some type of oven , blows the hoses/tubes. They said black stuff came out as expected.
I am noticing, and had not paid attention to this before, but soot measured and calculated are about even (~3g) first thing in the morning on idle. I press the gas to 2500rpm and meausred starts climbing while calculated stays about same. I got measured to 19g and let go off the gas. I figured it would begin to climb down but remained the same. If i stepped on gas again, it would continue to climb.

Took off to work, about 15 mile drive. Soot measured of course climbed until it got to about 25.3g. At that point CEL for P2459 came on. I was monitoring DPF Regen time since last regen and about the 13th mile, it started counting from 0 again. I looked at soot measured and it was climbing back down. Parked, kept engine on. At this time Soot measured was at 9g. Stepped on gas and got it up to 14g. Let go off gas and again, it remained.

So, i believe regens are happening since soot levels are coming down while driving and the countdown from last regen resets.

The fact that soot reaches 24g-25g in such short distance has to be an issue?

The fact that soot measured remains high after letting go off gas can't be right?

Ideas, suggestions, trouble shooting tips please. Thanks

The following is freeze frame on CEL fault:

http://imgur.com/a/mn97veI

 

[AverageAndy]

I wouldn't worry about the measured soot. I used to watch it and you are right, it seems to fluctuate. My soot mass calculated however, climbs pretty consistently, roughly 1gm/20miles driven (mostly highway), until I reach ~22gm at which point a regen will initiate, if all other parameters are met. If I drive to complete a regen, it will generally come down to around 5.25gm.

 

[jhort]

Thanks for comment. Thing is when meausured soot reaches 24g it sets CEL, P2459. Yours does n't set the CEL when reaches 24g or more?

 

[AverageAndy]

Mine never reaches 24gm or more calculated. Not sure about measured as I stopped following that a while ago. Also, no codes.

I have over 120k miles on the current DPF and have exceeded the 70gm ash load limit a few months ago. Trying to beat @d2freeman record of 98gm by getting to 100gm ash load lol! My load limit increases by 0.1/regen, which currently is happening about every 325 miles. So, I think I will have to drive another 95-100k miles to get there (currently at 176k).

 

[jhort]

Interesting. So now i'm wondering if it's the measured or calculated setting the CEL, or perhaps the actual pressure being read from the differential pressure sensor, which in turn sends the signal of soot mass calculated/measured. What i notice on mine is that measured soot climbs steadily from say 5g; calculated stays around 9g while meausred is steadily climbing. When measured reaches 24g, i notice calculated "suddenly" matches measured, so now both at 24g and is when CEL comes on.

So, seems from what your are saying is that the calculated is what sets CEL, not measured?

 

[LukesCRUA]

I have the exact same problem , been trying to find out why… as well. Yes measured values slowly climb up to 24g which then calculated spot value will just match at 24 and start regen, (post fuel injection and higher exhaust temps) until it comes down to 5.99g measured shuts the regen off. Calculated value for me can go down to almost 0g but it will still continue regenning until ‘measured value’ goes to 5.99g . It’s puzzling. I do 2 regens a day and drive 80km each way . ( an hour each way)