Why do I see "nd" for 3 values?

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Tiger55
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Why do I see "nd" for 3 values?

Post by Tiger55 » Fri Nov 27, 2020 3:15 pm

Hi, I drive an AUDI A6 AVANT 4G 3.0 TDI QUATTRO COMPETITION, 10-2017. I use the CARISTA Adapter and installed today the VAG DPF full version app to monitor my regeneration since I suspect something is not working correct.

QUESTION: Why do i see "nd" for 3 parameters on the display ? OIL ASH RESIDUE, LOW PRESS EGR CLOSING and DPF OUTPUT GAS TEMP
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$_10.JPG

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Re: Why do I see "nd" for 3 values?

Post by admin » Fri Nov 27, 2020 5:38 pm

nd means that the answer from the ecu doesn't match what the app expects.
This usually happens when the engine isn't tester neither verified yet, and this is the case: I didn't tested it and I didn't received feedbacks of correct working of the app with it.

I see you didn't customized the engine group: I suggest you to try to check every engine group changing it manually in the options and let me know if you have best results with other engines (means less or no nd fields).

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Fri Nov 27, 2020 8:00 pm

ok, thx for that tipp, I did try out all various groups (but only ignition on, engine off in the garage) and with Group 10 I get the best result: alle values are there, only DPF OUTPUT GAS TEMP is missing, maybe because engine was off !?
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Screenshot_20201127-195150.png

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Sun Nov 29, 2020 12:15 am

Today I drove the car and the DPF OUTPUT GAS TEMP stays red and "nd". So I asked myself, is this an issue with the APP ? Because DPF INPUT GAS TEMP is displayed ... and in all other APP Screenshots I saw from others there was alomst never an issue with these values. OR is this a sign that this sensor is maybe not working ?

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Re: Why do I see "nd" for 3 values?

Post by admin » Mon Nov 30, 2020 9:51 am

To get an answer from the ECU is enough to have the ignition on, then some value can be 0 but without errors (if the request is correct).

You don't see the output gas because the app is not configured correctly for your engine.
In some other group can you see the output gas temperature value? In this case I can merge all the valid parameters to create a new group for CVUB.
Otherwise you can only use the group 10 disabling the out gas temperature (tap on it) to avoid continuous reading errors. If in the future I'll be able to test a CVUB engine I'll update the app for it.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Wed Dec 02, 2020 8:20 pm

NO, unfortunately in no other group I see the DPF OUTPUT GAS TEMP - Group 10 was the best group, only this one parameter is missing there.
From other forums where I shared my screenshot I got the Feedback that the measured and calculated SOOD MASS parameter seems quiet low due to the fact the regeneration was more than 600km ago. So you are pretty sure the values are displayed are the correct car values - if they appear? I am still monitoring, not driving so much at the moment.
If you want, I am volunteering with my CVUB engine to do beta testing to show the DPF OUTPUT GAS TEMP. Just let me know!

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Re: Why do I see "nd" for 3 values?

Post by admin » Thu Dec 03, 2020 9:16 am

You're right, in your screenshot there are data not consistent.
You can log some trips and send me the file so I can check if there is some calculation error in the formula.
In the meantime you can verify these:
  • "Soot mass calculated" value should stay between about 2-3 grams and about 24 grams, it must increase slowly while driving and decrease quickly during regeneration reaching a value between 2 ando 8 grams depending on the driving style you have at the end of the process
  • "Distance since last regen" value should increase correctly following the car mileage
  • "Time since last regen" value should increase correctly following your clock
  • EGR field should stay at 100 when you depress the accelerator pedal and under 100 when you drive at constant speed
  • "DPF input gas field" should start at about the ambient temperature when you start the engine and should increase with engine on
  • post injections 2 and 3 should stay almost always at 0 and should have values more than 0 while regenerating
I have doubt also about the "Oil ash residue" field because the value is too low compared to your mileage.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Thu Dec 03, 2020 9:10 pm

Well, so far I only drove less than 100km since I installed the APP last weekend. I keep on monitoring. But all the values you listed look kind of good and reasonable to me. Time, milage, temperatures, etc.
Also the 0,04 Oil Ash Residue make sense, its 40ml out of ~ 175ml, kind of 1/4 before replacement ... I have 77.000km on the car

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Re: Why do I see "nd" for 3 values?

Post by admin » Fri Dec 04, 2020 2:21 pm

Ok good. So the next question is: how do you usually drive your car? Long trips in highways and few or no trips in city? This can be the reason why your soot mass is so low compared to the distance since last regen.

The oil ash could be ok, but not its percentage. I check the calculation behind.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Sat Dec 05, 2020 1:11 pm

My driving is very inconsistent. I mainly have the car for 60% business trips to clients all over Germany (then it would be long highway trips), and the remaining 40% are private trips in my local region, most likely a mix of 2-3km drives and 20-30km drives, not on highways, inner city and land roads only. Because of Covid I did not have many client visits this year, so the short private trips and seldom driving is this year the main profile. I got the car used in January this year, so since the beginning I have that unusual 2020 driving profile due to the circumstances. And I realized from the beginning... there are some weeks the car is not actively regenerating (no fan turning when i park), and sometimes I have several days in a row that every car ride the fan is spinning and I had recently 2x the warning message "Error particle cleaning system" even during driving (!) .. which disappeared the next day. This was the reason why I started more investigating since the AUDI garage couldn't find anything unusual. So I keep now monitoring with the APP (great tool) since during driving in the AUDI I have NO CLUE what the car is doing. AUDI missed in my opinion some kind of drive message about the regeneration needs and process.

As said, it would be great to also see for my engine the DPF OUTPUT GAS TEMP - as said I am ready for a BETA test any time or can provide ECU logging data to you if needed.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Sun Dec 06, 2020 1:09 pm

so, yesterday was the first time I saw the regeneration happening .. I drove 120km/h on a freeway - not sure if this was a passive or active regeneration (how can I figure that out?) - anyhow the App made a beep and the DPF became red, the process took 10 minutes and around 12km. Then the "last generated parameters" jumped back to zero. The process started with

Time (ms) Soot Mass Calc. (g) Regen. Duration (min) Distance Since Last Regen. (km) Time Since Last Regen. (min) Oil Ash Residue (g) Low Press. EGR Closing (%) DPF Input Gas Temp. (°C) DPF Output Gas Temp. (°C) Soot Mass Measured (g) Post injection 2 (mg/str) Post injection 3 (mg/str) Differential Pressure (hPa) Distance driven (km)

1607189120754 12.61 0 786 1227 0.04 100 346 18.23 0.00 0.00 175 77308

Immediatly BOTH Post Injection values went up. Attached is the Log ... you may have a look and confirm that everything looks as expected and all the values make sense .. from your APP perspective and what my car did.

1607189108632 12.60 0 786 1227 0.04 75 341 18.19 0.00 0.00 168 77308
1607189109474 12.60 0 786 1227 0.04 69 341 18.20 0.00 0.00 167 77308
1607189110293 12.60 0 786 1227 0.04 71 341 18.20 0.00 0.00 169 77308
1607189111071 12.60 0 786 1227 0.04 71 342 18.20 0.00 0.00 170 77308
1607189112094 12.60 0 786 1227 0.04 72 342 18.21 0.00 0.00 173 77308
1607189112958 12.60 0 786 1227 0.04 73 343 18.21 0.00 0.00 170 77308
1607189113834 12.61 0 786 1227 0.04 74 344 18.21 0.00 0.00 166 77308
1607189114698 12.61 0 786 1227 0.04 73 344 18.22 0.00 0.00 163 77308
1607189115431 12.61 0 786 1227 0.04 65 344 18.22 0.00 0.00 166 77308
1607189116284 12.61 0 786 1227 0.04 64 345 18.22 0.00 0.00 149 77308
1607189117419 12.61 0 786 1227 0.04 77 345 18.22 0.00 0.00 147 77308
1607189118323 12.61 0 786 1227 0.04 88 345 18.23 0.00 0.00 162 77308
1607189119164 12.61 0 786 1227 0.04 98 345 18.23 0.00 0.00 177 77308
1607189119984 12.61 0 786 1227 0.04 100 346 18.25 0.00 0.00 163 77308
1607189120754 12.61 0 786 1227 0.04 100 346 18.23 0.00 0.00 175 77308
1607189121657 12.61 0 786 1227 0.04 100 346 18.26 1.49 1.24 181 77308
1607189122634 12.61 0 786 1227 0.04 100 347 18.26 2.99 2.53 180 77308
1607189123445 12.61 0 786 1227 0.04 100 347 18.26 4.12 3.55 182 77308
1607189124338 12.61 0 786 1227 0.04 100 347 18.27 5.37 4.60 184 77308
1607189125153 12.61 0 786 1227 0.04 100 348 18.27 6.60 5.68 186 77308
1607189125982 12.61 0 786 1227 0.04 100 350 18.27 6.64 5.81 191 77308
1607189127175 12.61 0 786 1227 0.04 100 353 18.27 6.67 5.89 194 77308
1607189128099 12.61 0 787 1227 0.04 100 358 18.27 6.79 5.89 197 77308
1607189128981 12.61 0 787 1227 0.04 100 363 18.28 6.87 5.96 199 77308
1607189129724 12.61 0 787 1227 0.04 100 367 18.28 7.19 6.02 201 77308
1607189130494 12.61 0 787 1227 0.04 100 373 18.28 7.40 6.17 198 77308
1607189131356 12.61 0 787 1227 0.04 100 378 18.29 7.49 6.18 202 77308
1607189132525 12.61 0 787 1227 0.04 100 388 18.30 7.96 6.29 201 77309
1607189133393 12.61 0 787 1227 0.04 100 394 18.31 8.54 6.47 203 77309
1607189134279 12.61 0 787 1227 0.04 100 402 18.31 9.28 6.53 198 77309
1607189135116 12.61 0 787 1227 0.04 100 408 18.32 9.35 6.71 184 77309
1607189135966 12.61 0 787 1227 0.04 100 415 18.32 9.32 6.79 170 77309
1607189137036 12.61 0 787 1227 0.04 100 421 18.32 9.41 7.31 141 77309
1607189137914 12.61 0 787 1227 0.04 100 428 18.33 9.46 7.68 164 77309
1607189138909 12.61 0 787 1227 0.04 100 433 18.34 6.88 5.99 202 77309
1607189139776 12.61 0 787 1227 0.04 100 440 18.35 6.50 5.84 215 77309
1607189140654 12.61 0 787 1227 0.04 100 447 18.35 7.11 7.86 225 77309
1607189141454 12.61 0 787 1227 0.04 100 454 18.37 8.42 8.34 220 77309
1607189142617 12.61 0 787 1228 0.04 100 464 18.37 9.21 8.50 209 77309
1607189143322 12.61 0 787 1228 0.04 100 469 18.38 9.37 8.50 209 77309
1607189144188 12.61 0 787 1228 0.04 100 475 18.39 9.40 8.49 209 77309
1607189144972 12.61 0 787 1228 0.04 100 482 18.39 9.44 8.49 206 77309
1607189145907 12.61 0 787 1228 0.04 100 487 18.40 9.40 8.51 202 77309
1607189147053 12.61 0 787 1228 0.04 100 492 18.40 9.19 9.17 197 77309
1607189147911 12.61 0 787 1228 0.04 100 499 18.42 8.69 10.70 182 77309
1607189148772 12.61 0 787 1228 0.04 100 504 18.42 9.08 10.95 204 77309
1607189149723 12.61 0 787 1228 0.04 100 509 18.43 9.18 10.91 203 77309
1607189150617 12.61 0 787 1228 0.04 100 514 18.43 9.05 10.90 202 77309
1607189151443 12.61 0 787 1228 0.04 100 520 18.45 8.88 10.86 196 77309
:
1607189772515 6.79 0 805 1238 0.04 100 647 7.28 6.60 6.72 22 77327
1607189773335 6.79 0 805 1238 0.04 100 645 7.28 6.65 6.75 22 77327
1607189774223 6.79 0 805 1238 0.04 100 642 7.28 6.41 6.70 21 77327
1607189775083 6.78 0 805 1238 0.04 100 640 7.28 6.61 6.79 22 77327
1607189775974 6.78 0 805 1238 0.04 100 638 7.28 6.55 6.82 21 77327
1607189777161 6.78 0 805 1238 0.04 100 635 7.28 6.60 6.83 21 77327
1607189777900 6.77 0 805 1238 0.04 100 634 7.28 6.58 6.83 21 77327
1607189778583 6.77 0 805 1238 0.04 100 632 7.28 6.60 6.84 21 77327
1607189779247 6.77 0 805 1238 0.04 100 630 7.28 6.06 5.94 24 77327
1607189780103 6.77 0 805 1238 0.04 100 629 7.28 4.92 4.82 25 77327
1607189780963 6.76 0 805 1238 0.04 100 627 7.28 3.67 3.65 22 77327
1607189782035 6.76 0 805 1238 0.04 100 624 7.28 2.13 2.18 24 77327
1607189782873 6.75 0 0 0 0.04 100 621 7.28 0.00 1.12 28 77327
1607189783793 6.75 0 0 0 0.04 100 619 7.28 0.00 0.00 24 77327
1607189784710 6.74 0 0 0 0.04 86 617 7.28 0.00 0.00 19 77327
1607189785601 6.74 0 0 0 0.04 76 615 7.27 0.00 0.00 18 77327
1607189786790 6.73 0 0 0 0.04 73 613 7.27 0.00 0.00 17 77327
1607189787691 6.73 0 0 0 0.04 78 610 7.27 0.00 0.00 18 77327
1607189788567 6.72 0 0 0 0.04 96 608 7.27 0.00 0.00 24 77327
1607189789291 6.72 0 0 0 0.04 91 606 7.27 0.00 0.00 22 77327
1607189790132 6.72 0 0 0 0.04 89 604 7.27 0.00 0.00 22 77327
1607189790961 6.71 0 0 0 0.04 89 603 7.27 0.00 0.00 21 77327
1607189792031 6.71 0 0 0 0.04 89 601 7.27 0.00 0.00 36 77327


2nd QUESTION: Several times before I saw in the log that sometimes the Post injection 3 is going up just a little ... what is the car doing there ???

1607179299269 12.11 0 749 1180 0.04 84 255 14.88 0.00 0.00 16 77271
1607179300132 12.11 0 749 1180 0.04 83 255 14.88 0.00 0.00 16 77271
1607179300900 12.11 0 749 1180 0.04 83 255 14.87 0.00 0.00 16 77271
1607179301659 12.11 0 749 1180 0.04 83 255 14.87 0.00 0.00 17 77271
1607179302530 12.11 0 749 1180 0.04 83 255 14.86 0.00 0.00 16 77271
1607179303555 12.11 0 749 1180 0.04 83 255 14.86 0.00 0.00 16 77271
1607179304469 12.11 0 749 1180 0.04 83 255 14.86 0.00 0.00 26 77271
1607179305339 12.11 0 749 1180 0.04 85 255 14.85 0.00 0.92 32 77271
1607179306268 12.12 0 749 1180 0.04 83 255 14.86 0.00 1.09 29 77271
1607179307081 12.12 0 749 1180 0.04 87 254 14.85 0.00 0.85 33 77271
1607179307879 12.12 0 749 1180 0.04 100 253 14.85 0.00 0.00 63 77271
1607179308974 12.12 0 749 1180 0.04 84 252 14.85 0.00 0.00 45 77271
1607179309799 12.12 0 749 1180 0.04 80 251 14.84 0.00 1.46 43 77271
1607179310580 12.12 0 749 1180 0.04 70 251 14.83 0.00 1.39 29 77271
1607179311383 12.12 0 749 1180 0.04 66 249 14.82 0.00 1.38 26 77271
1607179312160 12.12 0 749 1180 0.04 65 249 14.82 0.00 1.52 23 77271
1607179313078 12.12 0 749 1180 0.04 59 249 14.81 0.00 1.15 21 77271
1607179314149 12.12 0 749 1180 0.04 63 247 14.82 0.00 0.94 21 77271
1607179314850 12.12 0 749 1180 0.04 62 247 14.81 0.00 1.37 18 77271
1607179315642 12.12 0 749 1180 0.04 62 247 14.82 0.00 1.37 18 77271
1607179316497 12.12 0 749 1180 0.04 64 246 14.83 0.00 1.37 18 77271
1607179317284 12.12 0 749 1180 0.04 64 245 14.83 0.00 1.36 18 77271
1607179318140 12.12 0 749 1180 0.04 64 245 14.83 0.00 1.36 18 77271
1607179319224 12.12 0 749 1180 0.04 64 244 14.84 0.00 1.36 18 77271
1607179319949 12.12 0 749 1180 0.04 63 243 14.84 0.00 1.22 18 77271
1607179320829 12.12 0 749 1180 0.04 65 243 14.85 0.00 1.35 18 77271
1607179321690 12.12 0 749 1180 0.04 73 242 14.85 0.00 1.52 19 77271
1607179322510 12.12 0 749 1180 0.04 78 241 14.85 0.00 1.52 20 77271
1607179323639 12.12 0 749 1180 0.04 77 241 14.86 0.00 1.51 20 77271
1607179324420 12.12 0 749 1180 0.04 70 240 14.86 0.00 1.48 20 77271
1607179325174 12.12 0 749 1181 0.04 69 240 14.86 0.00 1.38 20 77271
1607179325993 12.12 0 749 1181 0.04 65 239 14.86 0.00 1.20 20 77271
1607179326789 12.12 0 749 1181 0.04 63 238 14.86 0.00 1.07 21 77271
1607179327588 12.12 0 749 1181 0.04 63 238 14.87 0.00 1.07 20 77271
1607179328548 12.12 0 749 1181 0.04 65 238 14.86 0.00 0.68 20 77271
1607179329252 12.12 0 749 1181 0.04 61 237 14.86 0.00 0.00 18 77271
1607179329978 12.12 0 749 1181 0.04 68 236 14.88 0.00 0.00 18 77271
1607179330698 12.12 0 749 1181 0.04 84 236 14.87 0.00 0.00 22 77271
1607179331613 12.12 0 749 1181 0.04 87 236 14.88 0.00 1.29 24 77271
1607179332431 12.12 0 749 1181 0.04 100 235 14.88 0.00 0.00 40 77271
1607179333459 12.12 0 749 1181 0.04 90 235 14.88 0.00 0.00 54 77271
1607179334321 12.12 0 749 1181 0.04 100 234 14.89 0.00 0.00 137 77271
1607179335078 12.12 0 749 1181 0.04 98 234 14.88 0.00 0.00 115 77271
1607179335941 12.12 0 749 1181 0.04 0 235 14.87 0.00 0.54 63 77271
1607179336796 12.12 0 749 1181 0.04 61 236 14.84 0.00 1.45 32 77271
1607179337518 12.12 0 749 1181 0.04 63 236 14.82 0.00 1.43 30 77271
1607179338660 12.12 0 749 1181 0.04 64 236 14.81 0.00 1.04 26 77271

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Re: Why do I see "nd" for 3 values?

Post by admin » Sun Dec 06, 2020 3:37 pm

Data looks ok, but you cut the regeneration phase in the log. Not a problem.

I see your engine started the regeneration because it's reached the mileage or time limit, not for soot accumulation, in fact you can see that the regeneration was started at 12,61 grams instead of the commo value near 24 grams. The ECU has these 2 limits to avoid risk of fire in case of some sensors failure or, as in your case, if the driving style doesn't generate soot accumulation enough.
This can be explained if you drive usually in highways where the engine can regenerate without the intervention of the ECU (passive regeneration). Above about 120 km/h the engine gas temperature is high enough to burn the soot in the filter.

2nd question: it's normal, the ECU sometimes pilots second and third post injections to reduce noise and emissions.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Sun Dec 06, 2020 10:19 pm

see attached the graphics for the logged data of the last 180km since I use the App ...
Attachments
Analyse.jpg
Post Injections.jpg

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Re: Why do I see "nd" for 3 values?

Post by admin » Wed Dec 09, 2020 9:44 am

Everything seems ok but the soot mass calculated: you should keep checking it in next days/weeks to verify if every time the regeneration starts at about the same value. In this case it could be possibile a calculation error in the formula I used for your engine.

Logging data you can also verify what's the soot mass medium increment per kilometer, with it we can understand if it's a reasonable value compared to similar engines.

Tiger55
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Re: Why do I see "nd" for 3 values?

Post by Tiger55 » Tue Jan 19, 2021 10:38 pm

still monitoring ... it looks quite good, ~ 750km I see active regeneration.

ONE MORE QUESTION: Sometime when I drive longer on a highway I see the DPF icon in the App getting light red for a few mintues, but without active regeneration. What does this tell me ?

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Re: Why do I see "nd" for 3 values?

Post by admin » Wed Jan 20, 2021 12:05 pm

Since some release ago, I introduced 2 different filter image areas that can change its color: the external area depends on the output gas temperature and the internal area depends on the regeneration process.
In your case, the output gas temperature was high enough to change the external color. This function helps to understand when the gas temperature is near to the value required for the passive regeneration in which the soot mass increases slowly or remains quite constant.

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