Carprog A15 cable (Kline, 12V, GND) problem

Hello everyone. I have a problem with my Carprog and the cable A15

I want to read an airbag directly and have GND, Kline and 12V connection on the A15 connector.


Now I have noticed that Kline (red) also has 12V and only 2V for (wire yellow-12v), even though a 12v power supply is
connected.

Is it normal that the K-line (wire red) is also 12V?

And how can I fix that cable yellow gets 12V again