Connect new control units to the K-line.

Hello everyone,

I own an Audi A4 B5, manufactured in 1996, and I'm experiencing the following problem: I've installed a diagnostic-capable control unit (immobilizer pump), and another one is likely to follow (aLWR Stg). I would now like to access these units via the OBD port. I've already successfully used a 2x2 > crocodile clip adapter for the coding, but accessing the OBD port would be much more convenient.

Unfortunately, I haven't found any information on how the diagnostic bus is set up, and I'm hesitant to experiment on a system with multiple control units with a high replacement cost. The wiring diagram shows the control units connected to a "combination processor in the control unit housing"... can this be understood as a bus hub? Or is it more like a large terminal block? For example, can I safely connect the K-line of the immobilizer without any problems (or, if necessary, using a power sniffer) to the ABS control unit, or would I need to use this hub if it exists?

Greetings

Hi

If the Steuergeräte come from the same vehicle or the same model, you only need to connect the K-Line. Either directly to another Steuergerät or directly to the OBD connector. I also retrofitted the seat memory in my Golf, and here 2 CAN and 1 K-Line connections were required for diagnostics.

I hope I could help.

Best regards

Hello,

This is exactly what I was looking for. As I said, experimenting with the control units is always a bit of a gamble. I'll now connect the new components under the back seat, near the ABS control unit, to the K-line. Thanks a lot.

Best regards.