Hi all,
Before getting into question, small intro would be appropriate, I believe:

1:> After having my CAT replaced (with German non original), started to have white/grey'ish smoke, which come occasionally. Noticed that it starts to come 4-5 days after long run. Had white smoke problem in 2016 when living at Helsinki, replaced the injectors with refurbished one's and problem had gone, so this time had them replaced with brand new Bosch made. As smoke continued on periodic bases, replaced engine oil as well, since some of forums are suggesting excessive oil can cause same smoking. Still I have it. Latest, had been suggested to clean DPF, as it looks like a result of emergency DPF regeneration.

2:> Before going into DPF cleaning and/or buying new one, decided to analyse, in remit of my abilities, what is happening with engine. Have my VCDS hooked-up for last 3 days, but realised, Measuring block list available on internet is not quite matching with what I am reading. Looking for 3 particular indications, (a) Conditions, on which ECU decides to trigger emergency DPF regen, (b) Obvious indications that DPF is clogged and lastly (c) Any abnormal sensory data, described in SSP 350/351 as cause to trigger regen.

3:> Last night, heading back to another 'reset' in my terms, have captured live data, unfortunately, file is too big to upload, sol will put some key points:
a) Having a smoke heading for 1H long run on M4

Tuesday 14 December 2021 15:57:39:20132-VCID:2A0DFF2FA0FBC31BD95-807E VCDS Version: Release 21.9.0 (x64) Data version: 20210903 DS330.0
4L0 910 401 K 3.0L V6TDI G001AG 0030
Group A: '101 Group B: '102 Group C: '103
Bin. Bits Bin. Bits Bin. Bits Bin. Bits Temperature prior Temperature Particle Filter Particle Filter Offset (no units) Bin. Bits (no units) Bin. Bits
TIME TIME Precatalytic Converter Different. Pressure Different. Pressure TIME
Marker STAMP STAMP °C °C mbar mbar STAMP
0.47 0 0 0 0 0.12 899 141.6 0 -14 0.29 8 0 3.6 0
0.99 0 0 0 0 0.65 899 141.6 0 -14 0.83 8 0 3.6 0
1.49 0 0 0 0 1.16 899 141.6 0 -14 1.33 8 0 3.6 0

On group 103, 3rd digit, according to my information is number of seconds since last regen has zeroed itself, when 1st digit reached '1' (dunno what that means) on 774'th second the 3rd digit had new value of '0' , on my view this is indication of regen completed
773.19 0 0 0 0 772.84 899 619.5 36 -14 773.02 1 0 4.5 0
773.68 0 0 0 0 773.35 899 619.5 36 -14 773.52 1 0 4.5 0
774.2 0 0 0 0 773.85 899 619.5 36 -14 774.02 1 0 4.5 0
774.71 0 0 0 0 774.37 899 619.5 36 -14 774.54 1 0 4.5 0
775.23 0 0 0 0 774.88 899 619.5 36 -14 775.07 1 0 0 0
775.73 0 0 0 0 775.4 899 619.5 36 -14 775.57 1 0 0 0
776.25 0 0 0 0 775.9 899 619.5 36 -14 776.08 1 0 0 0

Value before '-14' is actual DPF pressure diff sensor reading, which reached max of 71, but on RPM average of 2,000 was on value of 21 milibars.

So, question 1 here is: What are normal operational conditions of PDF ? What indicates that PDF is blocked ?

Little history here: Reason I have changed CAT was flexy joint, which was leaking and making terrible noise, so from the point of replacement, all exhaust gases escaping from the hole needed to go into DPF. Here we come to another question:>> what is back pressure in exhaust pipe:
- What else can trigger PDF regen if DPF filter itself is clean >> Example PDF readings from resting place just before my return journey >> PDF carbon mass actual is zero

Group A: '101 Group B: '102 Group C: '104
Bin. Bits Bin. Bits Bin. Bits Bin. Bits Temperature prior Temperature Particle Filter Particle Filter Offset Particle Filter Particle Filter Particle Filter Mileage
TIME TIME Precatalytic Converter Different. Pressure Different. Pressure TIME Oil Ash Volume Carbon Mass (calc.) Carbon Mass (act.) Since last Regen
Marker STAMP STAMP °C °C mbar mbar STAMP km
0.28 0 0 0 0 0.44 899 253.7 0 -14 0.1 0.95 5.5 0 30
0.77 0 0 0 0 0.94 899 253.7 0 -14 0.6 0.95 5.5 0 30
1.27 0 0 0 0 1.45 899 253.7 0 -14 1.1 0.95 5.5 0 30
1.79 0 0 0 0 1.96 899 253.7 0 -14 1.62 0.95 5.5 0 30
2.31 0 0 0 0 2.47 899 247.8 0 -14 2.15 0.95 5.5 0 30


Switching to LAMDBA sensor today, as it seems to be able to measure back-pressure in exhaust pipe,
-----------------------------
042 Lambda probe

1) Air mass throughput
[-]
2) Ambient temperature
[°C]
3) Lambda probe pressure
[mbar]
4) Oxygen concentration
[mV]

043 Lambda probe
1) Engine speed
[rpm]
2) Exhaust gas temperature at lambda probe
[°C]
3) Exhaust gas counterpressure
[mbar]
4) Exhaust gas mass flow
[-]
-------------------------------------
have collected live data, but failed to interpret it. Lambda sensor reading, at least on group 050 stayed same during most of my journey

Wednesday 15 December 2021 15:08:30:20132-VCID:2A0DFF2FA0FBC31BD95-807E VCDS Version: Release 21.9.0 (x64) Data version: 20210903 DS330.0
4L0 910 401 K 3.0L V6TDI G001AG 0030
Group A: '040 Group B: '041 Group C: '042
Lambda Voltage Duty Cycle (no units) (no units) Duty Cycle Voltage (no units) (no units) Temperature Absolute Pres. Voltage
TIME TIME TIME
Marker STAMP % V % STAMP % V STAMP °C mbar V
0.12 -5 0 1 1 0.28 0 2 5 1 0.44 0 12.6 1020 0
0.61 -5 0 1 1 0.79 0 2 5 1 0.95 0 12.6 1020 0
1.11 -5 0 1 1 1.28 0 2 5 1 1.47 0 12.6 1020 0
1.63 -5 0 1 1 1.8 0 2 5 1 1.96 0 12.6 1020 0


So questions:

1:> What are indications of clogged PDF ?
2:> What else can be reason of having white-gray'ish smoke, appearing 4-5 days after field regeneration and disappearing after PDF regeneration again ?
3:> What are indications of regen requested by ECU, diff stages of process? 4th digit of group 101 supposed to say this, but it stayed constant during whole journey.
101 Emergency regeneration
Only on vehicles with particulate filter
Note:
With this measured value block fault causes can be located
if the emergency regeneration was aborted by the engine control unit

1) Em. regen. Enable conditions 1
Before start of emergency regeneration:
0 0 0 0 0 0 0 0 OK, because no emergency regeneration active
After start of emergency regeneration:
1 1 1 1 1 1 1 1 All enable conditions 1 OK
X X X X X X X 1 Minimum waiting time before start of emergency regeneration
with engine running was observed
X X X X X X 1 X Coolant temperature above 70 °C
X X X X X 1 X X Oil temperature above 70 °C
X X X X 1 X X X Ambient air pressure high enough
X X X 1 X X X X Fuel temperature below 70 °C
X X 1 X X X X X Battery voltage adequate
X 1 X X X X X X No clutch pressed
1 X X X X X X X No gear engaged
2) Em. regen. Enable conditions 2
Before start of emergency regeneration:
0 0 0 0 0 0 0 0 OK, because no emergency regeneration active
After start of emergency regeneration:
1 1 1 1 1 1 1 1 All enable conditions 2 OK
X X X X X X X 1 Road speed = 0
X X X X X X 1 X Engine speed in range
X X X X X 1 X X Injection quantity in permissible range
X X X X 1 X X X Accelerator pedal not pressed
X X X 1 X X X X Particulate filter temperature in permissible range
X X 1 X X X X X Pre-catalyst temperature in permissible range
X 1 X X X X X X Soot mass in particulate filter in permissible
Range
1 X X X X X X X No fault memory entries leading to
disabling of emergency regeneration
3) Em. regen. Abort conditions
X X X X X 1 After monitoring time temperatures not
reached
--> Cause: Consumers not switched on,
ambient temperature too cold
X X X X 1 X Temperature for particulate filter exceeded
X X X 1 X X Temperature for pre-catalyst exceeded
X X 1 X X X Abort via enable conditions
--> See zone 1 or 2
X 1 X X X X Abort due to total regeneration time
--> Cause: Consumers not switched on,
ambient temperature too cold
1 X X X X X Abort by diagnostic tester
4) Em. regen. Phase
000 Start emergency regeneration or not activated
001 Warm-up
010 Regeneration active
100 Cool-down



So bottom line is that I need to reach a point of better understanding of measuring blocks of Audi V6 BUG engine. Strangely enough, no DTC or any indication on dash board of anything wrong or emergency DPF cleaning in progress.


Your feedback on my problem and/or how to find correct documentation will help me a lot to clear this.

Many thanks in advance, Stay safe,
Guray