VAG-COM Diagnostic Thread

[MotherTucker]

This thread is intended as a place to collect and share VAG-COM control codes and diagnostic procedures in the R8.

What is a VAG-COM? It is a special cable and a Windows based software program that allows you to view and modify the data used by the various computers inside the car. It works with all VW and Audi models. It connects to the Data Link Connector which is by the driver's left knee, and your computer's USB or Serial port. The cable works as a copy protection device (dongle), and the software is available for free download.

Where can I get one? Buy it directly from the manufacturer Ross-Tech. http://www.ross-tech.com I use the HEX-USB+CAN model. It costs about $350 USD. Or, find someone nearby that has one, and trade the use of it for a ride in your R8

What will it allow me to do? You can modify the control codes to do things like turn off the seatbelt chime, adjust how the electric windows work, diagnose and potentially adjust engine tuning, turn on things like the european fog light, etc. You can also read any error codes that the car throws, to get the detailed error information, and you can reset (turn off) error codes. Note that if you modify the wrong stuff, you can mess up your car as well. You are advised to keep good notes about any values you change, so you can change them back if they don't do what you want.

How will I know which control codes to change? Some of the control codes are known by Ross-Tech and are documented in the program (VCDS) when you run it. But due to the limited number and newness of the R8, many of the R8-specific codes are still to be determined. That's the purpose of this thread, to collect those as they are discovered. There is also a Wiki on the Ross-Tech site.

For further information, please see the VAG-COM Diagnostic Forum on the VWVortex site. It's hosted by Andy from Ross-Tech and has tons of helpful information. http://forums.vwvortex.com/zerothread?id=1201719

[MotherTucker]

Here's some good snippets of info from other discussions here on R8Talk, from before this thread existed.

Remote window operation in US cars has never been a factory code in any of the last 10 years of Audi's I have owned. It is easily reprogrammed using a VAG tool and knowing the proper coding numbers. I have done it on a S4, RS6, and TT, but not yet on my R8 as I have not found the proper codes to use yet. Dealer may do it, but many may not know how to. Enough people tinker with the "cheaper" cars so these procedures are easy to find in other forums.

The VAG codes for the R8 are the same as A3 and TT. Should be easier to look those up, but I have to say that Ross Tech has improved their R8 long-coding support significantly in the last few software updates...

This may not be completely true however:

I just tried to do the window coding on an R8, I found two different sets of coding for A3s, but neither of them worked. I'm wondering if the coding is different for an '09 R8 and I just need to find someone who has an '09 A3 that has done the coding. Either way, i'll post something if I find out, or look forward to reading a post if someone else has figured it out.

Well I did succeed in turning off my seatbelt chime. In Module 17 (Instruments) Control Code, I set the second digit from the right (previously an 8) to a zero. Yay, at least that works.

But the long coding support that Ross-Tech has for the windows being controlled with the remote control is confusing. According to the long coding helper, it's already active. There must be other bits somewhere to set, there were when I did it on my GTI. Then the dealer upgraded my software in that car, and wiped it out. Ugh.

mt

AUX is activated by changing coding via VAG.

STG 56 (Navigation System) -> Coding -> Function 07

0xxxx?x: Options I
1 - default
2 - Digital-Radio
3 - Satelite-Radio
4 - Satelite- and Digital-Radio
5 - AUX in (US sw 0260+)
6 - AUX in and DAB (Us sw 0260+)

After bravely toggling bits blindly and trying to see what difference it made to the car, I learned a great deal about controlling DRL behavior. First of all, you can make almost any lights on the car function as daytime running lights: fogs, headlamps, side markers, tail markers, LEDs, or various combinations of these. But more importantly, I uncovered the single bit that keeps the DRL on the signal side from going out.

I won't post the entire coding of my CEM here, because that only encourages folks who don't know any better to cut and paste into their own cars. And blindly transferring VW/Audi's long coding is a recipe for disaster. Rather, I will only describe the particular bit that needs changed, as that will provide all the necessary information to anyone who knows how to use the tool properly, but won't encourage others do damage to their cars.

The bit can be found at:

Module address 09 (Central Electronics)
Submodule 0 (Master Cent. Elec. box, rather than a slave module)
Byte 3 (fourth from the left)
Bit 7 (first bit from the left in the binary representation, bottom check box in the VAG-COM long coding helper).

In cars like mine that "winked" from the factory, this bit is set to 1. (My original coding for Byte 3 was 91 in hex, or 10010001 in binary). Flipping this bit to 0 (in my case, making Byte 3 read 11 in hex, or 00010001 in binary) makes the DRLs stay lit on both sides when signaling. Simple as that.

[desperado]

Thsnks MT for starting this thread. I have the VAG-COM, but am not a skilled user at all. This thread should help remedy that!

[AnOutsider]

I haven't mastered the windows via remote or the rear light when driving, but I did manage to get my LEDs to stay on when I have my turn signal on (I hated that, always made the car look broken or something)

Go to the central electronics module... long coding. Go to byte 8 and toggle bit 7. Now my line of LEDs remain on when the DRLs are active and I've got my turn signal on.

[swansailor]

I haven't mastered the windows via remote or the rear light when driving, but I did manage to get my LEDs to stay on when I have my turn signal on (I hated that, always made the car look broken or something)

Go to the central electronics module... long coding. Go to byte 8 and toggle bit 7. Now my line of LEDs remain on when the DRLs are active and I've got my turn signal on.

I don't know if there is a difference between the 08 and 09 .... on mine (08) the lights do stay on when the turn signal is operating.

[AnOutsider]

Is this when you have DRLs on or full on headlights? In mine (and many others I suspect) if you have your lights on AUTO and DRLs are on (the LED strip), if you turn your signals on, the strip goes away

[Andyuk911]

MT, excellent thread ... for people in the UK, a lot of guys have cables on Audisrs and RS246

[MotherTucker]

Thanks. Hopefully it will collect lots of control codes.

As for the LED/Turn Indicators, there was a change to that by the factory. I have an early '09, and the LEDs stay on. A fellow R8 owner with an '09 that was delivered 6 months later has the new styke where they go out. I checked his MMI to get the version of his car. Our cars are both USA spec cars, both 2009's. Both of ours are Software version 0260. But his Hardware version is 16, and mine is 15. But apparently the control codes affect it?

mt

[AnOutsider]

Hmm.. who knows (other than Audi), but for anyone "afflicted" with the issue, there's your fix

I also hear the all-LED headlamps perform differently as well.

[650Berg]

Thanks. Hopefully it will collect lots of control codes.

As for the LED/Turn Indicators, there was a change to that by the factory. I have an early '09, and the LEDs stay on. A fellow R8 owner with an '09 that was delivered 6 months later has the new styke where they go out. I checked his MMI to get the version of his car. Our cars are both USA spec cars, both 2009's. Both of ours are Software version 0260. But his Hardware version is 16, and mine is 15. But apparently the control codes affect it?

mt

Just to not confuse anybody...the R8 does not come fitted with MMI, only an RNS-E navigation unit.