[T6_measured] Monitoring DPF regeneration, DPF condition, EGR operation

mmi · 5 Aug 2023

@ebiii
Attached an addendum to Torque - containing the following T6 PIDs

"T6-01 Lambda"

"T6-01 NOx sensor"

"T6-01 Particle sensor current"

"T6-01 Particle sensor operation time"

NOTE: "T6-01 Particle sensor operation time" will be logged only once in 10 seconds - to not unnecessarily slow down logging. However, the others are logged at maximum speed to catch all the fine details.

How-to import:

Torque > Main > Settings > Manage extra PIDs/Sensors > Settings (top right) > Import CSV file

How-to setup logging:

Torque > Main > Settings > Data Logging & Upload > Logging preferences/Select what to log > Settings (top right) > Select what to log > Scroll down to find/tick the above.

At this time perhaps add only the two PIDs related to particle sensor - not to slow down the logging too much. Of course can try with all of them - shouldn't be too bad anyways.

NOTE: the logging and the dashboard are separate/independent things - however, having the same data item in both doesn't slow down logging as Torque is quite smart combining the data.

n10n · 5 Aug 2023

mmi said:
Take 2 - brought a few obviously related parameters along the same time axis as earlier.

The exhaust temperature sensor S4 should be near the particle sensor. I would expect the IDE08340 be the indicator of detected soot. Obviously need to provide an update for Torque settings to @ebiii

IDE08721 IDE08340 IDE07984 IDE09420 IDE07990 IDE07987 IDE04090
2022-02-11 Particle sensor: time in op. mode measurement Particle sensor: measuring current calculated [µA] Particle sensor: cleaning deviation reaction time Heat quantity for dewpoint end: particle sensor Particle sensor: surface temperature Particle sensor: exhaust temperature Exhaust temperature /S1/S2/S3/S4
14:35:22 0 0 0 0 13.8 -0.4 /8/-13/-15/-13 °C
14:37:27 0 0 0 0 198.8 0.3 /201/64/35/1 °C
14:38:46 0 0 0 0 200.8 4.6 /196/102/83/69 °C
14:39:39 0 0 0 0 200.8 4.7 /321/150/101/66 °C
14:40:56 0 0 0 0 198.8 5 /368/189/155/66 °C
14:42:04 0 0 0 0 200.8 7 /360/221/202/83 °C
14:43:11 0 0 0 0 200.8 11.2 /461/261/236/142 °C
14:44:19 0 0 0 0 198.8 14 /306/266/272/188 °C
14:45:27 0 0 0 0 200.8 19.3 /421/303/297/235 °C
14:46:31 0 0 0 0 198.8 20.3 /305/282/297/258 °C
14:47:43 0 0 0 0 200.8 20.3 /473/305/293/270 °C
14:48:53 0 0 0 100 317.8 20.5 /349/282/301/265 °C
14:49:55 0 0 0 100 608.8 21.9 /540/334/281/270 °C
14:51:06 58.5 0 0.109 100 198.8 22.8 /410/312/314/290 °C
14:52:14 126.2 0 0.272 100 195.8 22.2 /409/314/315/288 °C
14:53:21 193.9 0 0.446 100 189.8 22.1 /412/304/297/287 °C
14:54:30 261.8 0 0.608 100 180.8 20.9 /447/301/294/276 °C
14:55:38 329.6 0 0.768 100 186.8 21.7 /435/295/281/272 °C
14:56:46 397.4 0 0.937 100 198.8 22.6 /447/318/319/286 °C
14:57:53 465.6 0 1.126 100 198.8 22.6 /430/306/300/291 °C
14:58:58 0 0 0 100 504.8 22.4 /415/305/300/280 °C
15:00:17 0 0 0 100 488.8 23 /504/325/306/284 °C
15:01:11 61.9 0 0.113 100 207.8 23.2 /443/312/309/293 °C
15:02:27 130.5 0 0.271 100 207.8 22.8 /448/318/315/290 °C
15:03:31 198.3 0 0.421 100 191.8 21.9 /334/297/302/288 °C
15:04:47 265.9 0 0.583 100 195.8 21.6 /442/304/294/279 °C
15:05:43 333.6 0 0.745 100 186.8 21.6 /424/298/294/275 °C
15:07:02 401.6 0 0.889 100 183.8 20.5 /382/299/295/272 °C
15:08:01 469.4 0 1.073 100 180.8 19.9 /456/299/288/271 °C
15:09:14 537.4 0 1.253 100 175.8 20.3 /339/282/268/265 °C
15:10:21 0 0 0 100 283.8 20.3 /353/307/311/266 °C
15:11:29 0 0 0 100 287.8 20.2 /347/299/288/282 °C
15:12:36 0 0 0 100 280.8 20.8 /439/307/289/267 °C
15:13:43 0 0 0 100 275.8 22.8 /389/303/301/272 °C
15:14:52 0 0 0 100 293.8 21.5 /247/283/318/289 °C
15:16:02 0 0 0 100 290.8 21.2 /251/260/271/293 °C
15:17:06 0 0 0 100 280.8 18.9 /367/285/282/253 °C
15:18:15 0 0 0 100 272.8 19.6 /372/290/284/254 °C
15:19:24 0 0 0 100 274.8 21 /396/306/321/265 °C
15:20:32 0 0 0 100 287.8 20.4 /434/301/290/282 °C
15:21:39 0 0 0 100 280.8 21 /400/299/291/270 °C
15:22:47 0 0 0 100 275.8 20.4 /394/288/279/265 °C
15:23:54 0 0 0 100 275.8 19.2 /214/236/271/257 °C
15:25:01 0 0 0 100 268.8 18.2 /453/283/260/254 °C
15:26:11 0 0 0 100 267.8 18.5 /421/278/262/239 °C
15:27:17 0 0 0 100 269.8 18.1 /378/284/275/245 °C
15:28:27 0 0 0 100 264.8 18.4 /406/285/272/245 °C
15:29:29 0 0 0 100 272.8 17.2 /302/261/272/242 °C
15:30:41 0 0 0 100 264.8 18 /390/276/254/245 °C
15:31:50 0 0 0 100 262.8 17.7 /463/291/271/237 °C
15:32:53 0 0 0 100 259.8 19.4 /404/297/286/242 °C
15:34:05 0 0 0 100 272.8 20.9 /397/291/289/267 °C
15:35:12 0 0 0 100 272.8 21.1 /455/293/283/269 °C
15:36:20 0 0 0 100 274.8 22.7 /486/310/299/273 °C
15:37:27 0 0 0 100 285.8 22.8 /235/268/284/284 °C
15:38:35 0 0 0 100 287.8 20.1 /167/225/288/269 °C
15:39:43 0 0 0 100 282.8 18.9 /168/215/258/265 °C
15:40:51 0 0 0 100 282.8 18.1 /214/192/185/237 °C
15:41:58 0 0 0 100 269.8 17.6 /334/228/217/223 °C
15:43:07 0 0 0 100 264.8 15.7 /343/236/212/195 °C
15:44:56 0 0 0 100 264.8 15.5 /300/210/210/198 °C
15:46:10 0 0 0 100 272.8 15 /173/180/199/194 °C

Note: The snippet is an extract of a continuous recording stream of all engine parameters thus the sampling rate is quite slow (once per 70 seconds - because of 1495 parameters being recorded).

You have obiviously noted this already as marked in bold but interesting anyway how the sensor does it’s own regen heating before the actual measurement cycle begins. Maybe, being after DPF, the exhaust temperatures are never high enough to base sensor regen on exhaust only. Or simply because same sensors are probably used in wide variety of different engines.

Some other remarks:

Winter time… particle sensor exhaust temperature seems interesting. Maybe the sensor has it’s own mini-exhaust that goes straight to open air?
Can’t get my mind around what the IDE09420 means. Perhaps not significant at all but maybe worth checking out on some cold really moist morning if it’s ever different than 0 or 100.
Might be coincidental but exhaust temp S1 peaks right at when particle sensor surface temp does
IDE07984 is also bit of a mystery. It has a rising trend throughout the measurement, maybe some kind of a quality metric of the measurement? Hard to tell, would need to dive more into how particle sensors work

ebiii · 5 Aug 2023

mmi said:
@ebiii
Attached an addendum to Torque - containing the following T6 PIDs

"T6-01 Lambda"
"T6-01 NOx sensor"
"T6-01 Particle sensor current"
"T6-01 Particle sensor operation time"

NOTE: "T6-01 Particle sensor operation time" will be logged only once in 10 seconds - to not unnecessarily slow down logging. However, the others are logged at maximum speed to catch all the fine details.

How-to import:
Torque > Main > Settings > Manage extra PIDs/Sensors > Settings (top right) > Import CSV file

How-to setup logging:
Torque > Main > Settings > Data Logging & Upload > Logging preferences/Select what to log > Settings (top right) > Select what to log > Scroll down to find/tick the above.

At this time perhaps add only the two PIDs related to particle sensor - not to slow down the logging too much. Of course can try with all of them - shouldn't be too bad anyways.

NOTE: the logging and the dashboard are separate/independent things - however, having the same data item in both doesn't slow down logging as Torque is quite smart combining the data.

Thank you ! it's getting more and more interesting ! I'll update the torque and do some more logging and analysis ! And I'll catch up with the messages from the last 2 days

n10n · 5 Aug 2023

n10n said:
You have obiviously noted this already as marked in bold but interesting anyway how the sensor does it’s own regen heating before the actual measurement cycle begins. Maybe, being after DPF, the exhaust temperatures are never high enough to base sensor regen on exhaust only. Or simply because same sensors are probably used in wide variety of different engines.

Some other remarks:

Winter time… particle sensor exhaust temperature seems interesting. Maybe the sensor has it’s own mini-exhaust that goes straight to open air?

Can’t get my mind around what the IDE09420 means. Perhaps not significant at all but maybe worth checking out on some cold really moist morning if it’s ever different than 0 or 100.

Might be coincidental but exhaust temp S1 peaks right at when particle sensor surface temp does

IDE07984 is also bit of a mystery. It has a rising trend throughout the measurement, maybe some kind of a quality metric of the measurement? Hard to tell, would need to dive more into how particle sensors work

This looks interesting :geek:

https://www.nanoparticles.ch/archive/2010_Baars_PR.pdf

Some quick takeaways:

Temperature has to be higher than dew point for the measurement to start, I suppose otherwise part of exhaust liquidifies and resistance measurement goes awry
Afaiu measurement works so that it measures until a threshold resistance (or time?) is reached. The time to reach the threshold is compared to a model map value of a similar driving cycle to decide pass/fail outcome
IDE08340 should indeed be the ”soot metric”. However it’s not linear - the absolute amount of soot during measurement cycle depends heavily on eg rpm so the current by itself is not enough

ebiii · 6 Aug 2023

Just logged a bit on small trips with the new settings, here is my log, I'll perform some analysis soon !

mmi · 6 Aug 2023

Indeed the particle sensor is registering something...

Did you also get any of the faults codes?

ebiii said:
P226D00 - Particle filter damaged or substrate missing Intermittently
P24B100 - Particle sensor measurement electrode short-circuit to positive pole Intermittently
P24B000 - Particle sensor measurement electrode short-circuit to ground Intermittently

Zoomed in

Well below the 10 minutes...

ebiii · 6 Aug 2023

mmi said:
Indeed the particle sensor is registering something...

Did you also get any of the faults codes?

View attachment 208704

Zoomed in
View attachment 208706

Well below the 10 minutes...

Well, no I just have a consistent P226D00 (intermittent but consistent motor light) since I replaced the EGR valve, (and P226D was present before the change as well). Do you see something fishy?

n10n · 7 Aug 2023

Thank you @ebiii for the data - now we know what the case of P226D might look like from the sensor perspective!

To me it looks like the particle sensor is working as expected. Combined with @mmi noting the measurement cycle is <10 min and the sensor operation PDF I linked earlier, it looks like the measurement cycle ends early due to measured soot levels reaching the simulated threshold value.

This probably confirms the earlier diagnosis of a partially shot DPF, it has a crack or some other damage that lets some soot through to the exhaust. Most likely a MOT failure and the soot might eventually degrade post-DPF sensors by covering them to soot. Other than that, I don’t think there’s immediate danger of breaking more components as the DPF still seems to perform regens normally and the differential pressures seem normal so probably the crack is a small one and let’s other systems function normally. That said, I’m not an expert so take above with a healthy dose of salt.

ebiii · 7 Aug 2023

n10n said:
Thank you @ebiii for the data - now we know what the case of P226D might look like from the sensor perspective!

To me it looks like the particle sensor is working as expected. Combined with @mmi noting the measurement cycle is <10 min and the sensor operation PDF I linked earlier, it looks like the measurement cycle ends early due to measured soot levels reaching the simulated threshold value.

This probably confirms the earlier diagnosis of a partially shot DPF, it has a crack or some other damage that lets some soot through to the exhaust. Most likely a MOT failure and the soot might eventually degrade post-DPF sensors by covering them to soot. Other than that, I don’t think there’s immediate danger of breaking more components as the DPF still seems to perform regens normally and the differential pressures seem normal so probably the crack is a small one and let’s other systems function normally. That said, I’m not an expert so take above with a healthy dose of salt.

Thank you for your analysis, it's very plausible. One thing though, I passed the MOT successfully even with that problem (I erased the error but the emissions were not flagged as abnormal). A garage is advising ultra-sound cleaning but I think that now we know more about this error than most garages.
I think that as long as MOT passes there is no problems keeping it like this as long as I watch the regen and the pressure regularly.

Would be interesting to have it cleaned and check the data again

mmi · 7 Aug 2023

Yes indeed - thank you @ebiii for sharing the log files. It's something I haven't seen before - definitely a good reference for future. I agree with @n10n's analysis.

ebiii said:
Well, no I just have a consistent P226D00 (intermittent but consistent motor light) since I replaced the EGR valve, (and P226D was present before the change as well). Do you see something fishy?

Good thing it's "only" P226D although a kind of mystery what were the other two glitches (which a kind of were pointing to the sensor or it's wiring).

After clearing the fault do you get the it back on the next trip or does the ECU "double-check" the failure before manifesting it as a fault code?

ebiii · 7 Aug 2023

mmi said:
Yes indeed - thank you @ebiii for sharing the log files. It's something I haven't seen before - definitely a good reference for future. I agree with @n10n's analysis.

Good thing it's "only" P226D although a kind of mystery what were the other two glitches (which a kind of were pointing to the sensor or it's wiring).

After clearing the fault do you get the it back on the next trip or does the ECU "double-check" the failure before manifesting it as a fault code?

The p226D faut appears immediatly if I scan, however not before about 200 km on the car's dashboard.

mmi · 7 Aug 2023

ebiii said:
The p226D faut appears immediatly if I scan, however not before about 200 km on the car's dashboard.

Thanks - a good piece of information.
Have you checked the code with Torque - I would expect the fault would be "pending" the first 200 km. See post#2 >> [T6_measured] Monitoring DPF regeneration, DPF condition, EGR operation

ebiii · 7 Aug 2023

mmi said:
Thanks - a good piece of information.
Have you checked the code with Torque - I would expect the fault would be "pending" the first 200 km. See post#2 >> [T6_measured] Monitoring DPF regeneration, DPF condition, EGR operation

Exactly it's pending. I have read the following :

"The error P226D means that the MSG is reported less differential pressure than expected in corresponding operating situations. If so much exhaust gas escapes through a defective EGR pipe that there is a total lack of exhaust gas volume at the DPF inlet, the differential pressures also fall out of the software window and the error message appears. That would be an explanation.....

However, if the error occurs with an intact exhaust system (no leaks), the differential pressure sensor or the lines must be checked."

Do you think there is a way to spot a leak between engine and dpf ? Maybe with the air intake data ? Or maybe it's a wrong idea but I think checking leaks makes sense. In the meantime I'll check for leaks with the soapy water method, it seems effective.
What I cannot comprehend is that if the metrics are ok, how can the ECU spot a cracked DPF (it could be soot build up not matching the differential pressure meaning a crack)

n10n · 8 Aug 2023

Well, you have soot in a tailpipe and particle sensor giving current readings >0.

These symptoms correspond exactly to the test situation in the particle sensor test setup in the PDF I linked in post #64. Here the DPF filter is drilled with holes to get a constant soot flow through the filter, where there should be none normally.

So, the leak would be within DPF, not to/from air.

> What I cannot comprehend is that if the metrics are ok, how can the ECU spot a cracked DPF

This is why the particle sensor is there in the first place - it’s job is to detect any soot particles getting through DPF. Your particle sensor readings were not ok, ”Particle sensor current” metric rising and test cycle lasting less than 10 minutes.

That said, ofc there can be other faults as well but this is what the data we’re looking at now points to.

ebiii · 8 Aug 2023

n10n said:
Well, you have soot in a tailpipe and particle sensor giving current readings >0.

These symptoms correspond exactly to the test situation in the particle sensor test setup in the PDF I linked in post #64. Here the DPF filter is drilled with holes to get a constant soot flow through the filter, where there should be none normally.

So, the leak would be within DPF, not to/from air.

View attachment 208864

> What I cannot comprehend is that if the metrics are ok, how can the ECU spot a cracked DPF

This is why the particle sensor is there in the first place - it’s job is to detect any soot particles getting through DPF. Your particle sensor readings were not ok, ”Particle sensor current” metric rising and test cycle lasting less than 10 minutes.

That said, ofc there can be other faults as well but this is what the data we’re looking at now points to.

Oh I didnt get it the first time thanks ! It makes sense now ! So the real soot detector is the resistance/current in the sensor if I understood correctly.

n10n · 8 Aug 2023

ebiii said:
Oh I didnt get it the first time thanks ! It makes sense now ! So the real soot detector is the resistance/current in the sensor if I understood correctly.

Correct!

ebiii · 13 Aug 2023

Things are weird today, just logged for a long trip uninterrupted. Static P226D should have come as usually but didn't.

P226D is there unconfirmed for way longer than usual, but P0401 Intermittent appeared as well despote the New EGR.
Also noticed it lost a lot of water, but I guess it's just condensation.

I'll analyse the log attached when I get home

Edit: p226d is now confirmer but it tool way longer than usual
P401 totally disappeared, I relog to compare

mmi · 13 Aug 2023

ebiii said:
Things are weird today, just logged for a long trip uninterrupted.

Indeed. Thank you very much. Intriguing. :geek:

ebiii said:
Static P226D should have come as usually but didn't.

Perhaps a set number of driving cycles is also needed? When it was cleared last time?

Note: For some reason recording of exhaust temperatures did not start until 6973 seconds. They were set to use generic OBD PIDs - all the others are VW specific PIDs.

ebiii · 14 Aug 2023

mmi said:
Indeed. Thank you very much. Intriguing.

Perhaps a set number of driving cycles is also needed? When it was cleared last time?

View attachment 209566

Note: For some reason recording of exhaust temperatures did not start until 6973 seconds. They were set to use generic OBD PIDs - all the others are VW specific PIDs.

It was cleared by à non vw garage on Monday morning, did about 20km / day for 6 days and then about 300 km until it went back on. I dont think the leak has anything to do with as my AC stopped working few hours after the pictures

mmi · 7 Oct 2023

UPDATE:

A Torque extension to monitor actual AdBlue level and AdBlue range counter in ECU

revised in post #3 (direct link below)