# B8 A4 (8K) BCM2 controller and VCDS



## NJRoadfan (Sep 16, 2006)

Just looking for clarification here. During my research of retrofitting LEDs onto a B8 A4 (and A5s), I keep reading about how VCDS can't access and reprogram the BCM2 controller to turn off bulb diagnostics, etc. What exactly is preventing VCDS from making coding changes? I'm just curious because this might get in the way of other modifications of the car if other controllers are similarly locked out. It looks like Kufatec somehow made a one time use module to do the reprogramming (which doesn't work with US cars yet), but I would prefer using VCDS as it can reverse any changes.


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## Uwe (Jan 16, 2000)

*Re: B8 A4 (8K) BCM2 controller and VCDS (NJRoadfan)*

I'm not aware of any control module in an 8T or 8K car that we can't access or change the coding on. Please provide more information.
-Uwe-


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## rlarsen (Apr 8, 2009)

*Re: B8 A4 (Uwe)*

The retrofit of the tail light LEDs from Kufatec for A4/A5 B8, uses an area of the BCM2 where VCDS (Vag Com) doesn't have access - but the VAS does.
Or maybe the question is - how does VCDS get access to the 'secret' area??


_Modified by rlarsen at 1:58 PM 8-7-2009_


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## NJRoadfan (Sep 16, 2006)

*Re: B8 A4 (Uwe)*

Here are the vague references that I have found so far:
http://forums.vwvortex.com/zerothread?id=4436079
http://www.audizine.com/forum/...nt=48
http://forums.audiworld.com/sh...53280 (specifically post #8)


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## Theresias (Feb 11, 2004)

In the upper class Audi models the Comfort Control Module (J393/BCM2) controls the tail lights and the parameters in the control module software specify which type of tail lights are installed.
Officially the Audi parts catalog states that there are different control modules (or at least different software versions) for LED and normal tail lights as well as NAR (North American Region) and RoW (Rest of World).
The only official way to get LED tail lights working would be to install the proper control module to begin with as the software parameters I referred to cannot be altered with either the dealers VAS or VCDS. You claimed the VAS does support changing this, I just double checked but cannot find any proof of this. Could you supply more details regarding this, I am sorta skeptic on that part.
To be clear on our current level of information, a normal VAS without special access features cannot perform the function you would need to get this done and Audi of America as well as Audi Germany will not supply the details to do this. Which means the VAS is as useless as VCDS for this specific modification. We are not talking about a coding here, the proper term would be parameterization.
As far as I am aware the 3rd party modification you referred to does not work on all modules, actually it only works on a very few ones.
Since the J393 also contains immobilizer and remote control you cannot just install a RoW module which supports LEDs. If you would, you'd need to replace the existing remote controls with RoW ones as well. We have done quite a few 8K and 8T NAR > RoW conversions now to have an idea what works and what doesn't.


_Modified by Theresias at 2:14 PM 8-7-2009_


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## rlarsen (Apr 8, 2009)

*Re: (Theresias)*

Kufatec did the retrofit of my LED tail lights, and they did the coding manually - no re-flash of the unit with a dongle.
I don't know where they did the coding, because I was more or less kicked out when they did the coding - with a VAS. 
I did a scan of my Comfort Control Module (J393/BCM2) before and after the retrofit - no changes.


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## NJRoadfan (Sep 16, 2006)

*Re: (Theresias)*

That clears it up, thank you. It looks like the US cars now have a compatible BCM2 controller available to them (2010 A4/A5 come with LED tails), but one still has to get the remotes coded and deal with the SVM system. Looks like I'll be going with the regular amber tail lights anyway, the LED tails are pretty pricey and aren't even bi-color LEDs like the Mk5 Jetta/Golf units.


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## Theresias (Feb 11, 2004)

*Re: (rlarsen)*


_Quote, originally posted by *rlarsen* »_I don't know where they did the coding, because I was more or less kicked out when they did the coding - with a VAS.

Please see my reply above - it was no coding what they did and their VAS is not necessarily running normal software (meaning they may have the special features in question active).
Right now you are telling everyone it can be done with a VAS, people than assume their dealer can do it but this is misleading at best. The only way open for each and every one would be to replace the module with one supporting LEDs.
We have similar reasons as VW for not enabling that functionality in VCDS, making changes directly in the control module software is nothing even a skilled technician should deal with or even may be able to deal with.


_Modified by Theresias at 4:08 PM 8-7-2009_


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## rlarsen (Apr 8, 2009)

*Re: (Theresias)*

>> The only way open for each and every one would be to replace the module with one supporting LEDs.
The problem is then, that Audi won't activate the new module, so the one how have the MCM2 replaced with one ending with "BQ" _(or a newer one)_ with all Channels available, will have the light out fault.


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## NJRoadfan (Sep 16, 2006)

*Re: (Theresias)*

Sounds like Kufatec dumped the controller's firmware and hex edited a few values (a common hardware hacking practice) to disable the cold bulb diagnostics among other things and then rewrote it back to the BCM2 module. The location to change would vary by controller revision since its hard coded. What they are doing is extremely risky, particularly when dealing with "mission critical" systems in a car.


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## Theresias (Feb 11, 2004)

*Re: (rlarsen)*


_Quote, originally posted by *rlarsen* »_The problem is then, that Audi won't activate the new module...

If you refer to the component protection by "activate" your statement is definitly not true. No matter if the module fits the car or not in this case, the component protection can definitly be deactivated/learned by any Audi dealer.

_Quote, originally posted by *NJRoadfan* »_What they are doing is extremely risky, particularly when dealing with "mission critical" systems in a car.

Agreed.


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## rlarsen (Apr 8, 2009)

*Re: (Theresias)*


_Quote, originally posted by *Theresias* »_If you refer to the component protection by "activate" your statement is definitly not true. No matter if the module fits the car or not in this case, the component protection can definitly be deactivated/learned by any Audi dealer.

No, I refer to the removal of the warnings in DIS about "bulb out" - here the new BCM2 need to be 'approved' by Audi with its VIN - and Audi won't do that.
I think you know about Marcus _(from audi4ever.at and motor-talk.de)_ he retrofitted his LEDs with the right BCM2 (type: "BQ"), but Audi wouldn't approve his A4 as a valid car for this BCM2 type - so he had the "bulb out" warnings in DIS - I don't know what he has done right now - maybe he still has the warnings...


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## Theresias (Feb 11, 2004)

Audi will not update the SVM information for this vehicle in case of a non-authorized modification, this is supposedly what you refer to here. 
However, this missing/incorrect SVM information for the new module doesn't prevent from installing it. Only the SVM part will fail but that (coding/adaptation) can be done manually.
René, with all due respect it seems your level of insight here is not very deep but you are still claiming a lot of things which do not necessarily match the actual/realistic situation.


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## rlarsen (Apr 8, 2009)

*Re: (Theresias)*


_Quote, originally posted by *Theresias* »_Audi will not update the SVM information for this vehicle in case of a non-authorized modification, this is supposedly what you refer to here.

It was done by a Audi dealer... as a non-authorized modification







I don't know...

_Quote, originally posted by *Theresias* »_However, this missing/incorrect SVM information for the new module doesn't prevent from installing it. Only the SVM part will fail but that (coding/adaptation) can be done manually.

Yes, but how?

As I understand, you need to enter a SVM code - this code need to be generated _(if Audi won't give it to you)_, and you just happen to know how to do this - right?? 
If it is so easy, why is there no one _(as you've read about)_ who has been able to solve this problem?? and earned some money with it.

_Quote, originally posted by *Theresias* »_Rene, with all due respect it seems your level of insight here is not very deep but you are still claiming a lot of things which do not necessarily match the actual/realistic situation.

I will admit that I haven't tried the coding of the LEDs my self - I only refer to what others have reported, and "they" haven't been able to do it - not even the Audi dealers who have tried it.


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## luk2011 (Aug 9, 2009)

*We are not talking about a coding here, the proper term would be parameterization.*

*To be clear on our current level of information, a normal VAS without special access features cannot perform the function you would need to get this done*
Yes, it's true.
With parameterization can make this LED tail lights retrofit.
But first, you need to update the software version of BCM2.
You'll ned of version up to 0145
This parameterization can be done just with : *VAS5163 tester*
*VAS5163 have special diag service to write data record in ECU*
You need also of special param set file 
VAS5163 tester it's used for developement work for ECU supplier on VW group cars
For A4 8K Sedan ( B8 Limousine ), this can be done without to change the BCM2.
Only you'll need of update of software version of BCM2 and param set.

For A4 8K Kombie ( Avant ) and A5 8T you will need to change the BCM2, to have an OEM solution.
How Kufatec did it this retrofit ?
We don't know yet, just we supposed it.
_Modified by luk2011 at 8:37 AM 8/9/2009_

_Modified by luk2011 at 8:38 AM 8/9/2009_


_Modified by luk2011 at 8:43 AM 8/9/2009_


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