2012 Touareg CRCA , exhaust gas temperature

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liciniu
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Joined: Sat Mar 20, 2021 5:54 pm

2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Sun Mar 21, 2021 6:51 am

Dear all ,

I've bought your very useful app and use it because it is very light and quick to use ,though I couldn't match properly the engine group . My problem is that accordingly to my own exploration , and to Elsawin my car has only two exhaust gas temperature sensors although there are Touareg with four sensors (ex CATA engine equipped ). Interesting is that in VCDS the ECU is displaying also four value , but temperature for sensors no 2 and 4 are constant at 222°C as the car has no sensor 2 and 4. See the pictures please. So whatever group engine I choose , at best I have indication for sensor no 1 ( Input gas temp ) and 222°C for the Output gas temp because VAG DPF is reading the address for either sensor no 2 or 4 . Coul that be changed please ? Many , many thanks ,

Liciniu
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VCDS3.jpg
VAG_DPF.jpg

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admin
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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Mon Mar 22, 2021 12:30 pm

CRCA isn't present in the app database, so you're using the engine group 0 as default. This group reads temperature sensors 3 and 4 of your VCDS picture, but I've recorded also the other 2 values in my analysis so it's easy for me to change them for your engine. I'll create a new group for CRCA type.

I see the EGR value missing, is it missing also in all other engine groups?

liciniu
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Joined: Sat Mar 20, 2021 5:54 pm

Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Mon Mar 22, 2021 4:06 pm

Dear Admin ( would be nice to know your name )...

Thank you first for your good job , then thx for the quick reply .
I was not really keen on knowing the EGR cycle value , but indeed the value it is not present on the generic Group 0.
Instead the EGR reading is properly matched in the Groups : 1,2,3,6,7,8,10,11,16.
Indeed , I see now that VAG DPF is interpreting the CRCA's exhaust gas temperature sensor 3 as DPF input gas temperature , I didn't knew the other ( exhaust gas temperature sensor 4 as DPF output gas temperature ).
To conclude the CRCA needs G235 on IDE02229 , exhaust gas temperature sensor no 1 ( located in the turbo sub-assembly ) as DPF input value and G495 on IDE02234 as DPF output temperature ( although located upstream in DPF's body just before the honeycomb ) because there are no other real temperature readings on the exhaust system of the CRCA .
Actually on the CRCA ( and a lot of other engines ) there is a catalytic oxidizer between the turbo and the DPF . If we want to be precise these readings are rather the input and output of the catalytic oxidizer ...
Although again , it's a fantastic job you've done .
Attachments
CRCA.png

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Mon Mar 22, 2021 6:22 pm

Are you sure about the sensors location? Because the ECU needs to know input and output DPF temperatures to make its calculation.
It would be strange if the output gas temperature were missing.
I give a check also in my documentation to find more information.

About the EGR, the values of group 1,7,10,16 are for the low pressure EGR, the others are for high pressure EGR. Usually I prefer to show low pressure EGR because more useful. Can you verify if with group 1,7,10,16 the value is correct? It should stay at 100 while you accelerate and near 20-30 driving at constant speed with low rpm. Consider also that groups 7,10 and 16 share the same request, so you can check only groups 1 and 7.

After the EGR checking and the sensors choice, I'll create the new engine group.
dpf.jpg

liciniu
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Joined: Sat Mar 20, 2021 5:54 pm

Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Mon Mar 22, 2021 10:07 pm

Dear Admin ,

I understand your legit doubt . I had the same . But... I was unlucky to remove completely the exhaust system so I have some experience on my car now.
1. Searching ElsaWin for my car type, the term "exhaust gas temperature" is listing only two sensors G235 and G495.(see pic.)
2. Just to be sure , I've disconnected the sensor located in the DPF and right away I had the following error ( see the values for the other sensors also ):

5257 - Exhaust Gas Temperature Sensor; B1 S3
P242A 00 [032] - Malfunction
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 239777 km
Date: 2021.02.18
Time: 13:01:03

Engine RPM: 0.00 /min
Normed load value: 0.0 %
Vehicle speed: 0 km/h
Coolant temperature: 13 °C
Intake air temperature: 15 °C
Ambient air pressure: 970 mbar
Voltage terminal 30: 11.700 V
Unlearning counter according OBD: 39
Exhaust gas temperature sensor 1: 17.8 °C
Exhaust gas temperature sensor 2: 222.0 °C
Exhaust gas temperature sensor 3: 1000.0 °C
Exhaust gas temperature sensor 4: 222.0 °C
Shut-off timer: last engine shut-off time: 130948 s

3. Have a look at the full exhaust system with notes on the pic
4. More detailed look of the DPF ( see pic again )
5. I really understand that sometimes it does not make obvious sense , I'm just assuming that the ECU is doing a lot of calculations to substitute some values....for instance the differential pressure sensor is pneumatically connected on only one side , on the other there is a short loose plastic tube, I guess the output pressure of the DPF is very close to atmospheric pressure on that side , the ECU just measure and adjust the atmospheric pressure instead of the output pressure of the DPF
6. I'll have a deep look at the EGR values tomorrow just to be sure that I'm not misleading you .

All the best ,

Liciniu
Attachments
Elsawin.png
DPF.jpg
Exhaust.jpg

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Tue Mar 23, 2021 9:15 am

Very detailed information, I don't have reasons to doubt, I trust you.

Just to add more information to your knowledge, looking for CRCA engine in my stored documents I read this:

Official VW SSP495 reports 3 exhaust temperature sensors:
  • Exhaust gas temperature sender 1 G235
  • Exhaust gas temperature sender 3 (after catalytic converter) G495
  • Exhaust gas temperature sender 4 (after particle filter) G648
Official Elsawin database (you know) reports 4 exhaust temperature sensors:
  • Exhaust gas temperature sender 1 G235 (after turbocharger)
  • Exhaust gas temperature sender 2 G448
  • Exhaust gas temperature sender 3 G495 (after catalytic converter)
  • Exhaust gas temperature sender 4 G648 (after particle filter)

Attached you can see the related printscreen, some in italian but I added indications with red lines.
Let me know if there is something useful for you.

For sure if the sensors 2 and 4 have fixed 222°C values, they aren't useful for diagnostic. We need to know if VCDS reads data correctly or not (also ross-rech works with reverse engineering so errors are possible).
Attachments
ssp.JPG
G648.JPG
G495.JPG
G448.JPG
G235.JPG

liciniu
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Joined: Sat Mar 20, 2021 5:54 pm

Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Tue Mar 23, 2021 2:04 pm

Dear Admin ,

Thanks for the extra info. Just to be on the same side : I'm not challenging you, as your knowledge is far better on this field ( the proof is your app ) . The information on the VW group engines is very disseminated and often contradictory . I was aware of the SSP495 , however I believe that this is the general concept ( although is referencing explicitly the CRCA and the CJMA engines ) . I agree 100% on the SSP495's page 42 ,it is exactly what I have ( see a copy attached ). However I don't have this elusive :-)) dpf output gas temperature sensor , please have a look on the attached exhaust pipe pic ( out of the DPF's clamp top left , up to the rear silencer)...I rather believe that I most have a variation of the concept on my car ( btw PRCode: 7MQ = Emissions standard EU5 mod ) .
Also, are you 100% sure that the selected pictures are for the CRCA engine on the Elsawin ? Searching ElsaWin with Touareg ,2012, CRCA I have only two exhaust gas temperature sensors 235 & 495. Furthermore to cross-check I had a look on the ETKA parts program , searching ( again) for exhaust gas temperature sensor on the Touareg 2012 , see the pic to check that there are no output sensors (after diesel part.filter ) for the CRCA engine..
Long story short, I guess that the ECU is assuming that the DPF output exhaust gas temperature is 222C which is a very plausible temperature , and use it for further calculation ( therefore using almost the same software on all the variation of the engine ) . In fact if you want to keep on VAG DPF the field name as DPF Output Gas Temperature, then 222 is the answer..
Speaking about the app , just to add extra confusion,I can tell you that the EGR cycle has the same value of roughly 95% ,(matching the VCDS readings ) , at idle/ nominal coolant temperature , independent of the group 1,7,10,16 , basically the ECU is reporting the same duty cycle either on High or Low press EGR reading.Have a look at the pics again.
Thank you for your work ,
A dopo ,

Liciniu
Attachments
EGR-VCDS.jpg
EGR-Group7.jpg
EGR-Group1.jpg
ETKA.png
Exhaust_pipe.jpg
Exhaust_SSP495.png

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Wed Mar 24, 2021 11:35 am

I think you're right, there are only 2 temperature sensors in the exhaust line.
I checked again in Elsawin and I see a page referring to CRCA engine that contains only description of sensors 1 and 3, then I see other pages with details about all 4 sensors (of which I've sent the printscreens) but without references to CRCA engine, so I think these pages was wrongly linked to CRCA engine. It's strange because Elsawin should be used by official service, but ok.
Moreover the fixed 22 values confirm the lack of sensors 2 and 4.

In my app I can use sensor 1 as input temperature and sensor 3 as output sensor. This is wrong, but I prefer to fill both fields instead to make the output temperature field empty.
The temperature 3 will be a little lower than the temperature 1 while in a correct setup the output temperature follows the input one with a delay due to the filter presence between them.
I'm wondering if would be better to swap the 2 values to have sensor 3 as input DPF temperature, also because this value is used by the app to colorize the filter image. Maybe this can be optimized in the future seeing the app behavior.

EGR
Groups 1,7,10,16 read the same low pressure EGR value and groups 2,3,6,8,11 read the same high pressure EGR value. This is the reason why you find the same percentage for groups 1,7,10,16.
I'll use this value in the new CRCA engine group. I'd like to be sure it has correct values, have you checked if the percentage stays at 100% while you depress the accelerator pedal? 100% means EGR fully closed and without gas recirculation, so maximum engine performances.

liciniu
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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Thu Mar 25, 2021 1:31 pm

Dear A,

I'm happy that together we were able to clarify this engineering solution .
I'm 100 % sure about the EGR reading as I confronted it with the VCDS scan. Just for double checking I had a test today again and the EGR ( both high and low ) is reaching 100 % during WOT ( wide open throttle ) while idling is staying at 95-97% . Also the low pressure EGR is a little bit more dynamic , therefore it makes sense to keep it as reference in the main screen .
About the order input / output my two cents are that I would rather keeping them in their order down the exhaust stream , but is your call.

Wishing you all the best ,

Liciniu

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Thu Mar 25, 2021 5:33 pm

We can play with the parameter as we want because these is a new group so we don't need to keep compatibility with other engines.
For example I can set the correct input gas temperature using sensor 3 in the first field and "simulated particle filter surface temperature" value in the second field. It's not the standard setup, but we'd have 2 temperatures related to the DPF and the input value, used by the app for calculation, would be correct.
I keep searching for other better setup, but this one could be a good compromise.
I'll update you soon.

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Fri Apr 16, 2021 8:15 am

In last release I created a new group for CRCA engine with all working parameters. I decided to add input gas temperature and simulated DPF surface temperature.
Let me know if it works well

liciniu
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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Fri Apr 16, 2021 8:51 pm

JUst returned from a long trip...Without knowing it. I'll give it a try this weekend. Grazie.

liciniu
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Joined: Sat Mar 20, 2021 5:54 pm

Re: 2012 Touareg CRCA , exhaust gas temperature

Post by liciniu » Mon Apr 19, 2021 5:57 pm

So ,

I had some time for testing . Everything works fine , I've seen that you finally opted for an ECU calculated value for the DPF surface temperature , the IDE 04653 , which is basically following the DPF input temperature minus some assumed corrections. Makes sense , taking into consideration the application target ( monitoring the DPF , no other parameters ).
Thank you for your good job and promptitude.

All the best ,

Liciniu

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Re: 2012 Touareg CRCA , exhaust gas temperature

Post by admin » Tue Apr 20, 2021 8:11 am

Very good, thank you for your feedbacks and provided information.

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