BCM adaptation for MQB cars - "Leutche" & "Light configuration" channels

[DV52]

BCM adaptation for MQB cars - "Leuchte" & "Light configuration" channels

Fist, my apology for the long intro for my question.

I've been trying for some time to get my addled brain around the way that VW manages exterior lighting on MQB vehicles. With the help of forum colleagues (both here and elsewhere) I think that I now have an embryonic understanding of what I'm calling "Leuchte" programming and I have outlined a brief summary of this in a reply to a question by "cocopops" which you can find here. Now, I'm the first to admit that all this stuff is new to me, but I have been able to develop and implement a few tweaks based on my fledgling knowledge and surprisingly, they appear to work (which is a positive starting point)

I now have a database of the BCM adaptation channels for 5 different models of Mk7 Golfs. Three models are RoW and two are NAR vehicles. Regardless of the model and regardless of the installed lighting package, every one of these models has 665 adaptation channels that start with the term "Leuchte" and a further 665 Adaptation Channels that start with the term "Light Configuration". The structure of the adaptation channels for each function-set is identical . I have posted an example of the Leuchte structure here and the structure of the "lighting configuration" channels below:

438)-Light configuration-Lasttyp 23
(439)-Light configuration-BAP Bitposition 23
(440)-Light configuration-Fehlerort mittleres Byte DTC-DFCC 23
(441)-Light configuration-Lichtfunktion A 23
(442)-Light configuration-Lichtfunktion B 23
(443)-Light configuration-Dimmwert AB 23
(444)-Light configuration-Lichtansteuerung HD AB 23
(445)-Light configuration-Lichtfunktion C 23
(446)-Light configuration-Lichtfunktion D 23
(447)-Light configuration-Dimmwert CD 23
(448)-Light configuration-Dimming Direction CD 23
(449)-Light configuration-Lichtfunktion E 23
(450)-Light configuration-Lichtfunktion F 23
(451)-Light configuration-Dimmwert EF 23
(452)-Light configuration-Dimming Direction EF 23
(453)-Light configuration-Lichtfunktion G 23
(454)-Light configuration-Lichtfunktion H 23
(455)-Light configuration-Dimmwert GH 23
(456)-Light configuration-Dimming Direction GH 23​

The "Light configuration" channels are in rows 297 to 958 and the "Leutche" channels are in rows 1516 to 2028 of the following spreadsheet:
https://www.dropbox.com/s/4kbh0hb6j9smeyv/09 Adpmap_Golf Compare.xlsx?dl=0


So here's the guts of my question - to which I come seeking answers.

Whilst the structure of the channel descriptions for the two function sets are similar, their relationship is a mystery (to me at least). My current hypothesis (which is likely to be completely wrong) is that each Leuchte set (i.e. a set of 19 x adaptation channels) needs a twin "light configuration" set to operate. Further, I now believe that the tie between the two function-sets is the number at the end of the channel description (i.e. the number 23 in the example above and in my 2nd reply post to cocopops). Does this seem reasonable?

A second related matter to which I seek advice is a suspicion that I have that the "light configuration" channels are somehow related to setting-up the power supply settings for each external light (I don't know how this is done. but I assume through digitally controlled voltage regulators, or current regulators for LED lights). Is this reasonable and can anyone confirm that VW do this kind of thing in their cars?

 

[DV52]

"Leuchte" & " Light configuration" channels - more questions

OK, I know that I haven't waited a respectable amount of time for comments to my post above (incidentally, thanks for the "likes"), but I have a few more related questions.

After posting the questions above, a dichotomy has arisen! Whilst I have found some evidence in support of the hypothesis in my previous post, alas I've also found disturbing evidence that refutes the position that I have taken. I'm hoping that someone can unravel this new mystery!

Here's what I mean:
Of the 34 x channel-sets (i.e. a "set" being the collection of 19x Adaptation channels that are devoted to each external light) in the BCM for my 103TSI mk7 Golf, 11 x channels-sets are not active. Of the 23 channel-sets that are active, 6 x channels-sets appear to have a close correlation between the Leuchte channels and the Light configuration channels. The remaining 17 "active" channel-sets do not appear to have this correlation.

An example of the good correlation channel-set is the Left Daytime Running light below:

Notice that the stored value for "Lamp error" channels have the same hex numbers and that every time a Leuchte channel is "not active", the corresponding "light configuration channel has a "0" value. I think (but this is a guess too) that where the Leuchte channel has an entry like "Daytime Running Light", the corresponding Light configuration channel has a code (like "20" in this case).

An example of a bad correlation channel-set is the Left Back-up Lamp below

As is clearly evident, the stored value entries for the two functions are strange!

Why is this important I hear you thinking? Well, the principal reason for wanting to understand this matter is that when properly developing tweaks for the exterior lights on MQB vehicles, it might be necessary to change both the "Leuchte" AND "Light configuration channels. To date, those of us that have experimented with these tweaks have only concentrated on altering "Leuchte" channels.

So, is anyone willing to venture a possible explanation for these odd findings (for example, perhaps every exterior light doesn't need a twin pair to operate, or perhap my hypothesis is just the rantings of a deranged and mentally unhinged mind!)?

 

[mtl]

Why is this important I hear you thinking? Well, the principal reason for wanting to understand this matter is that when properly developing tweaks for the exterior lights on MQB vehicles, it might be necessary to change both the "Leuchte" AND "Light configuration channels. To date, those of us that have experimented with these tweaks have only concentrated on altering "Leuchte" channels.

Sadly, I do not know the explanation for this, but I have already done quite a few light tweaks on MQB vehicles (the last one was Octavia with xenon headlights and halogen front DRL; I turned of DRL and turned on fog lights as DRL with 50% luminosity) and on all tweaks only Leuchte channels were changed. I did not change any Light channels, but I also did not check if Light channels automatically changed after tweaks. Maybe this would be good idea to check and if you need any data, I could check next time.
Btw: great work, hope it will give a positive result.

 

[DV52]

Sadly, I do not know the explanation for this, but I have already done quite a few light tweaks on MQB vehicles (the last one was Octavia with xenon headlights and halogen front DRL; I turned of DRL and turned on fog lights as DRL with 50% luminosity) and on all tweaks only Leuchte channels were changed. I did not change any Light channels, but I also did not check if Light channels automatically changed after tweaks. Maybe this would be good idea to check and if you need any data, I could check next time.
Btw: great work, hope it will give a positive result.

Mtl: I do like the way your brain works!

So what you are suggesting is that rather than needing to change the Lighting control channels in concert with Leutche channels when implementing a tweak (which was my hypothesis), the lighting control channels could automatically change consequentially when the stored value in the Leucthe channel is altered. What a brilliantly elegant idea!

Your theory has the lighting control channels as a slave of the Leuchte channels - very neat indeed (go the the top of the class)! Given all this stuff is in its infancy, I'll going to call this mtl's first law of Leutche programming (if it is factual, of course)

 

[DV52]

mtl: Your theory has the lighting control channels as a slave of the Leuchte channels - very neat indeed (go the the top of the class)! Given all this stuff is in its infancy, I'll going to call this mtl's first law of Leutche programming (if it is factual, of course)

mtl: Update - I have the honour to inform you that "mtl's first law of Leuchte programming" is proved!! You were indeed correct in your hypothesis. I changed the stored value for a Leutche channel in a "close correlation" lamp and the stored value automatically changed to this altered value in the corresponding Light configuration channel (when it was re-polled). It would appear that the Light configuration channel sets mimic their Leuchte twin in a kind of master slave relationship. I have no idea why this is required, but it does appear to happen for "closely corrected" lamps.

Again well done and thank you for solving my mystery. As a prize for your inspired hunch, you have my undying gratitude!

I still have no idea why there are some lights with closely correlated Leuchte channels and Light configuration channels, and some without. But learning this stuff is very much a one-step-at-a-time process.

 

[mtl]

mtl: Update - I have the honour to inform you that "mtl's first law of Leuchte programming" is proved!! You were indeed correct in your hypothesis. I changed the stored value for a Leutche channel in a "close correlation" lamp and the stored value automatically changed to this altered value in the corresponding Light configuration channel (when it was re-polled). It would appear that the Light configuration channel sets mimic their Leuchte twin in a kind of master slave relationship. I have no idea why this is required, but it does appear to happen for "closely corrected" lamps.

Great, I am glad that this proved to be right, though really all the work is on you. I just added my thoughts.

Again well done and thank you for solving my mystery. As a prize for your inspired hunch, you have my undying gratitude!

Anyway, maybe just a two additional thoughts:
- it would be worth checking if correlation is mutual, so that if Light configuration change automatically changes corresponding Leuchte config.
- is it possible that those lights without Light configuration are physically not present? As for example: if the car has LED lights than Lights for LED is present, but not for halogen lights.

 

[DV52]

- is it possible that those lights without Light configuration are physically not present? As for example: if the car has LED lights than Lights for LED is present, but not for halogen lights.

mtl: again, thanks for sharing your further thoughts. I'm fairly sure that the non correlated lights are not related to LED/incandescent light inconsistencies. The example of a non correlated light that I posted earlier is for a Halogen light and the one below is for an LED light.

The 6 "closely correlated" lights are

1. Front Turn Indicator (left and Right)
2. Daytime Running Light (left and Right)
3. Low Beam Headlamp (left and Right)

The only thing that is common for these lights is the fact that they are all physically part of the front headlight assembly (though oddly, the high-beam lamp is not in this list). Do you have a view about the suggestion in my first post that maybe the "Light configuration" channels were used as some type of conditioning protocol for the power supply to these lights? If so, what's so special about these three sets of lights (and not others)?
Then there is the bigger question of why have so many "inoperative" adaptation channels in a control module which appear to be vaguely related to their "Leuchte" twins, but which appear to do absolutely nothing? German engineers are not renowned for such inefficiencies!!

This is messin' with my head, big time - damn VW ...hahaha!!

 

[DV52]

Update 16/11/2014: And another interesting observation in the saga above- It seems that the stored values in the "non correlated" Lighting configuration channels are not stable! Each time that I poll these channels, VCDS returns a different value !! What does that mean? This phenomenon doesn't happen for the 6 x "closely correlated" lights (i.e the values that VCDS returns for Lighting configuration channels are stable and they are consistent with their Leuchte twins).