Modules reporting zero code-string?

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DV52

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I'm stuffed if I can find the previous discussion on this forum regarding the propensity for some modules on newer MBQ vehicles to report a zero-series in their code-string.

Here's an example for the BCM from an Aussie 2017 Tiguan Highline Rline which I posted in the reference section some time ago

Code:
-------------------------------------------------------------------------------
Address 09: Cent. Elect. (J519)       Labels: 5Q0-937-08X-V2.clb
   Part No SW: 5Q0 937 084 CG    HW: 5Q0 937 084 CG
   Component: BCM MQBAB H   H34 0236  
   Serial number: 02001634700021
   Coding: 000000000000000000000000000000000000000000000000000000000000
   Shop #: WSC 01357 011 00200
   ASAM Dataset: EV_BCMMQB 017001
   ROD: EV_BCMBOSCH_017.rod
   VCID: 7F4EC694E6BCD4B822-802A
-------------------------------------------------------------------------------

I've been helping the owner of this vehicle recently and in the process of re-examining his BCM admap, I had a possible "road-to-Damascus" revelation (this will only make sense to catholic forum members here:D)

In older MQB vehicles, the facility to tell the BCM how the rotary lighting switch was configured was in the upper-nibble of Byte 7 - as in the picture below:

WR9Ve4V.png


Now, the wording for the light switch entry has been "Anglo-sized" by whoever @ Ross Tech develops these screens (I think), but the name given to the Light switch is LDS in other diagnostic devices that I own which quote the original German text - see the portion of long coding screen below:

Ki8aXZ1.png


Anyhow, it appears that in the case of the old Byte 7 facilities, the BCM for the 2017 Tiggy has an extra bunch of new adaptation channels related to the LDS as follows:
Code:
ENG10584-ENG10920-Außenlicht_uebergreifend-LDS_mit_AFL
ENG10584-ENG10919-Außenlicht_uebergreifend-LDS_mit_Nebel_Schlusslicht
ENG10584-ENG10918-Außenlicht_uebergreifend-LDS_mit_Nebellicht
ENG10584-ENG10921-Außenlicht_uebergreifend-LDS_mit_Standlichtstellung

So it seems that there has been a transfer of these functions from the code-string to adaptation channels! My quick perusal of some of the other old-code string descriptors also suggests that there are additional adaptation channels in the BCM admap with suspiciously close descriptors.

So perhaps VCDS isn't deliberately lying at all -perhaps there really aren't any code Byte/Bits in these modules!

Don

PS: the added role of adaptation channels in these newer modules might also explain why the channel count has risen to 1,800-ish
 
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PetrolDave

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I had a possible "road-to-Damascus" revelation (this will only make sense to catholic forum members here:D)

Actually to any Christian, not just Catholics.

Finding adaption channels that replace some (all maybe?) of the coding string values is very interesting, and raises the question why VAG would prefer to use adaptation channels instead of coding (obfuscation maybe?).

Great work DV52.
 
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DV52

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hmm.......... OK - I'm not so familiar with christian writings from other faiths but if St Paul (the Roman tax collector) is blinded by an all-merciful and omnipotent being in their religious text, then thanks for the correction (in truth, my casual aside was said tongue-in-cheek - I'm also not too au fait with the catholic stuff either - I'm a born again agnostic)!!

But your question is a good one - why indeed? For me, the issue goes back to fundamentals -what is the real difference between code and adaptation channels? I asked this very question on this forum when I first became infected with the OBD bug without a satisfactory answer. So I made-up my own theory about code relating to " establishing inputs" and adaptation channels related to "managing outputs" of each control system. But Uwe suggested with his usual kindness and with the upmost grace that perhaps my hypothesis was misplaced. Which means I don't know if there is any difference between the two, other than perhaps a historic preference for Byte/Bits in early modules (perhaps?).

But if VAG's decision on this matter is at all driven by their historic practices, I'd bet London-to-a-brick that there is a dollar saving in the move to make code-string obsolete!

Don

PS: but the more profound question is - what is the future for that very excellent part of VCDS that is called the "long coding helper"?

PPS: my fundamental credo: avoid obfuscation - life's way too short for this type of complication !!!
 
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PetrolDave

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PPS: my fundamental credo: avoid obfuscation - life's way too short for this type of complication !!!

100% agree - when I was working I always followed the KISS (Keep It Simple, Stupid) methodology.
 
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Uwe

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So perhaps VCDS isn't deliberately lying at all -perhaps there really aren't any code Byte/Bits in these modules!
I'm dismayed that you would even contemplate the possibility that VCDS would deliberately lie about this.

Adaptation channels do provide more flexibility than coding strings. Think about what you can do with a thousand or two adaptation channels vs. a few tens of bytes of coding.

-Uwe-
 
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DV52

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^^^ Yes, in retrospect, I now agree -it was a shameless and thoroughly reprehensible accusation!! :D (but I did enjoy making it)

Don

PS: At least now I have the answer that I asked in a previous post how many Bytes is too many?. From the recent 47 Byte ABS modules we now know that the answer is 48 (i.e. the same as the meaning of life and everything + 6)! So- 376 x Bits is the most that the boffins @ VAG will tolerate in any one control module!
 
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icardiag

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It's a well known fact that since summer 2016 some of the BCM modules used in MQB based cars have "zeroed" coding. Being specialized on Skoda cars, I can confirm it started with Skoda Superb MY17 and continued with Skoda Kodiaq MY17 and earlier this year with facelifted Skoda Octavia MY18. Same situation is with facelifted Golf or Leon.
All the coding capable features got transferred from coding to adaptation channels (which is good) and some of them got transferred to datasets (this ain't good).
Changing values of adaptations can be easily done with VCDS, bud uploading datasets cannot be done with VCDS. There are some other tools for this process (we won't name), but the main problem is, that you have to know WHAT exactly and WHERE exactly to upload. And here we're hitting a dead end here as most of these (I dare to say 99%) datasets are neither described nor publicly available. Changing a code/adaptation is a reversible operation - wrong code/adaptation? No problem, you can put the previous code/adaptation back and you're where you've stared. You've uploaded a wrong datased? Then you're deep in trouble, to fix this, you have to upload the correct data to correct address...
 
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DV52

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icardiag: Hi.

I respectfully bow to you better knowledge of VAG's doings in newer MQB based modules. My understanding was not as advanced and my findings came as somewhat of an epiphany (hence my road-to-Damascus analogy).

But thank you for the response - and for the dataset warning

Don
 
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