GRA errors after AHK installation, Roomster 2010

Hello,

I retrofitted a Westfalia tow hitch to our Roomster 1.6 TDI, which was manufactured in 10/2010.
Since then, I've been getting a GRA error.

Ideas:
1. Encoding error.

2. The (guilt-inducing) crimp connector on a CAN bus cable.
The others had popped out, but I couldn't get this micro pin out of the connector housing due to the tight space.

3. Some cable is damaged.

Attached are two log files.
The first time should be done immediately after the last trip, and the second time after clearing all errors and turning the GRA on and off once.

Does anyone have any ideas?

You should truly begin with checking the wiring.

If it's okay, could you try disconnecting the control unit (STG) completely and see if the GRA error disappears?

Thank you.

I was afraid that I might have to reach under the dashboard again.