Using the interface in an Audi A4 B6

Hello,

bin in dem CAN-Bereich ein Neuling und möchte mir das CAN-Interface-Kit zulegen. Es geht insbesondere um einen Audi A4 B6, es sollen aber auch zum Vergleich A4 B7 und A3 8P ausgelesen werden. Beim A4 B6 ist es ja nunmal so, dass er an der Diagnose-Buchse eigentlich keinen CAN hat. Ich habe dort den Antriebs-CAN hin gelegt und konnte erfolgreich via VCDS auf CAN-Steuergeräte (habe eine PDC-Steuergerät aus einem A3 8P drin) zugreifen. Gehe ich Recht der Annahme, dass ich so mit dem Interface auf dem Antriebs-CAN lesen und schreiben kann? Was ist in dem Fall mit dem Komfort- und Infotainment-CAN? Do I always have to replace the wiring at the diagnostic connector for that, or is access via this method simply not possible?

Greetings.

Hello,

The Audi A4 B6 (type 8E) does not use CAN for vehicle diagnostics up to and including the 2004 model year; consequently, the OBD2 connector is not connected to the corresponding pins.
Later/other Audi models, on the other hand, use CAN for diagnostics.

The diagnostic CAN bus in vehicles from the Volkswagen Group (Audi, Seat, Skoda, VW) usually doesn't initiate any communication on its own. You need to send a message, and if everything is done correctly, you will receive a response.

Quote:

Am I correct in assuming that I can read and write to the interface on the drive CAN in this way? What about the comfort and infotainment CAN in that case?

The RKS+CAN allows you to read and write data on all CAN buses, which is the intended purpose of the hardware.
You can't simply install control units into a vehicle and then connect the CAN bus to the diagnostic port, hoping that diagnostics will work (usually, the gateway control unit at address 19 is responsible for this). Also, you can't simply connect a 500 kBit/s bus (e.g., a CAN drive system) to the CAN infotainment system (100 kBit/s).

The RKS+CAN hardware is designed to be used as an interface for OBD (KOBD2Check or your own/other programs) or to be connected directly to the respective CAN buses in the vehicle (CAN drive, etc.) and to read/write data using KCANMonitor.

Best regards, Rainer.

Hello,

Thank you for your reply.

By temporarily connecting the power supply to the diagnostic connector (where others connect the diagnostic CAN), I was able to get it to power on, and I was then able to diagnose an A3 control unit through it using VCDS. I was surprised that it worked, but it did.

oder per Verbinder direkt zu den jeweiligen CAN Bussen im Fahrzeug (CAN Antrieb etc.) und lesen/schreiben per KCANMonitor.

What kind of connector is needed? Is there anything specific, like a terminal block or something? I didn't see anything like that in the shop or in the kit. It would be great if you could connect the three buses and easily read/write data with the KCANMonitor.

Hativ3 wrote:

What kind of connector is used? Is there anything special about it, like a terminal block or something? I didn't see anything like that in the shop or in the kit. It would be great if you could connect the three buses and easily read/write data with the KCANMonitor.

The kit includes an OBD2 connector where you can connect your desired cable.

Quote:

Lieferumfang: RKS+CAN Diagnosehardware, frei pinnbare OBD2 Buchse, Kabel mit Sub-D9 Stecker (CIA), Aufbewahrungskoffer.

"Personally, I use the OBD2 connector with a SUB-D9 connector according to the CIA standard (all necessary parts are included in the kit), and then a corresponding SUB-D9 connector is installed in the vehicle."
As a "connection point," the CAN gateway is a suitable option because all the buses converge there.

Okay, that's great. Can you connect them all at once and read the data, or do you have to read them one at a time?

Always just one.

I'd like to briefly chime in here...
I am also a beginner when it comes to CAN.
and I'm now considering purchasing the "CAN-USB Interface-Kit RKS+CAN"...

They write:

Quote:

Die RKS+CAN Hardware ist dafür gedacht, als Interface zur OBD genutzt zu werden (KOBD2Check oder eigene/andere Programme) oder per Verbinder direkt zu den jeweiligen CAN Bussen im Fahrzeug (CAN Antrieb etc.) und lesen/schreiben per KCANMonitor.

I would primarily like to use the latter option: "...by connecting directly to the respective CAN buses in the vehicle (e.g., CAN drive system) and reading/writing data using the KCANMonitor software..."
(because I already use a VCDS diagnostic system, specifically the KKL+CAN version, from Kaufmann)

my questions:

- If I understand correctly, with the aforementioned adapter and connector, I can access all CAN buses located in the vehicle (in my case, an Audi/VW), regardless of their speed?
(at least insofar as they comply with the physical layer standards of ISO 11898, correct?)

- Can I use the KCANMonitor software to periodically send specific CAN frames/IDs?

- Is there a kind of database within this forum that lists CAN IDs used in Audi/VW vehicles?

Hello freaxx,

freaxx wrote:

- if I understand correctly, I can access all CAN buses located in the vehicle (in my case, Audi/VW) using the aforementioned adapter via a connector, regardless of their speed?

Yes, it is possible to tap into, read, and transmit data from all the buses installed in vehicles by Audi/VW (which is generally what is meant by "CAN").

freaxx wrote:

- Can I use the KCANMonitor software to periodically send specific CAN frames/IDs?

Yes, it is even possible to send specific responses depending on the reception of certain messages.

freaxx wrote:

- gibt es hier im Forum eine Art Datenbank mit CAN-ID's welche in Audi/VW Fahrzeugen verwendet werden ?

Here in the forum, there are several corresponding databases or listings. However, these may vary depending on the model, year of manufacture, etc., so they should only be considered as a general reference, unless they happen to be exactly for the same vehicle model.

Best regards, Rainer.

OK, thank you again.
If you want to "sniff" a CAN bus in a vehicle, either an existing or a closed one, you should be able to "disable" the termination resistors in the adapter if necessary. How is this implemented?

Whether termination resistors are necessary or need to be removed depends on the specific bus.

By default, they are equipped with these features, but "without" is also an option.
If necessary, you can always connect external ones.

Best regards, Rainer.