FID issue in A3 8L without display -> Help with troubleshooting

Hello,
And now, to get to the point, I've been searching the internet for a long time and haven't found anything.

My A3 8L TDI (AHL) had a problem with the fuel gauge in the instrument cluster, so I replaced the old...
(8L0 920 900) was replaced with a new, used part (8L0 920 932 DX). The ECU was also retrofitted, and the sensor inputs for the lighting control unit and windshield washer were grounded.
Everything seems to be working fine so far.
Now I have connected the 3-pin connector from the Concert 1 to the combination unit.
The KI has a blue, green, and gray connector (32 pins). I have connected pin 11 to ena, pin 12 to clock, and pin 13 to data on the gray connector.
The radio (part number 4B0 035 186 E) is locked with the code 00205. "The '5' indicates a second display without a changer."
The KI (8L0 920 932 DX) is coded to 00040, and the adjustment in channel 60 is 1024, channel 61 is 1, and channel 62 is 1.
Despite this, the error message "No communication" is displayed in the KI (control interface) as well as in the radio system.
I've checked the wiring again, but there's no fault.
I'm slowly running out of ideas, which is why I'm posting this question in the forum – maybe someone will spot the error.
Perhaps the pin configuration on the DX KI is different, or it may not even have the 3-wire bus. Only CAN.
I am grateful for any help or feedback regarding any mistakes made.
Best regards, FredFeuerstein10.