CAN Distributor A4 2002 - For Sale

Hi!
Perhaps one of you can help me and tell me where the CAN bus distribution box (interior) is located in an Audi A4 from 2002. The problem is that there are communication errors registered in all the control units (ECUs) with other ECUs. Since a trailer hitch was installed some time ago, I suspect that the potential distribution box may not be properly connected. Or does anyone have better ideas?
Unfortunately, I am unable to provide you with the error code access or the specific error codes at this time.

Okay, here's the translation:

Thank you.
Dirk.
P.S.: Sorry for the brief error description!

There's no such thing as a 'CAN distributor.' Instead, there's a gateway, which is essentially the central hub. All the control units are connected to it. The gateway is located in the instrument cluster. If you disconnect it, you'll get a lot of error messages because of the lack of communication with the control units. A list of these error messages would be really helpful!

Hm. das würde mich jetzt aber sehr wundern, wenn es diese CAN-Potentialverteiler bei Audi nicht gibt. Aber möglich ist ja alles. Ich war nur davon ausgegangen, da DC diese in jedem Fahrzeug hat. SStrange.
According to your theory, this would mean that all CAN bus pairs would have to run individually to the combination point. With the number of ECUs involved, this would result in a very thick cable bundle, which would contradict the principles of the CAN bus.
Alternatively, there would only be a single ring topology, which I consider unthinkable from the perspective of the operational safety of the CAN bus.

Dirk.

'No, I may not have expressed myself correctly. The connections are bundled together within the cable harness, with separate pairs for CAN high and CAN low, just like other connections (e.g., terminal 31 or similar). Only twisted pairs of wires, specifically for the drive and comfort CAN buses, go to the instrument cluster.'

I once bought several cable harnesses on eBay and took a closer look at them. I became a little suspicious when I saw them. Apparently, the twisting and the out-of-phase transmission of the CAN signals are perfectly sufficient to protect against external interference. If it were up to me, there would at least be a shield around them.

I once saw a CAN bus distribution unit, similar to the one you're talking about, in the central electrical system of a T4. I think it was from around 1996, when the first CAN bus systems were introduced. It was a plastic component with two separate rows and many compartments where the CAN bus wires were plugged in.

Hello,
Twisted wires are extremely effective in preventing faults!
An external shield is only effective if it is 'unpowered,' meaning it is only 'grounded' on one side; otherwise, leakage currents can easily flow through the shield, which induces interference onto the signal lines.
Best regards,
Günther.

Hi!
I'd like to provide some feedback.
"mummelratz" is absolutely right with his description! There are no pre-wired potential distributors in the A4; instead, they are only soldered. You can find them, for example, at the bottom of the A-pillar of the passenger door.
Potentiometer-based distribution boxes were apparently only introduced by Audi starting with the A8 model.
Thank you again for your participation and your suggestions!
Dirk.