Retrofitting a tow hitch to an Audi A3 8V, production year 2020

Guten Tag. Vielen Dank für die Aufnahme.
We have an original tow hitch from AMAG installed in our Audi A3. Now we have a problem: it cannot be activated. The control unit is not recognized. Can you help me figure out how to activate the tow hitch?
Thank you for your help. (Unfortunately, I don't think I managed to upload the entire scan.)

"One error found:"
131655 - Trailer detection control unit (J345).
U1003 00 [009] - No communication.
[Timeout Node 0x47 / 69 - Trailer Detection Control Unit]
confirmed - checked since last deletion.
Environmental conditions:
Error status: 00000001
Error priority: 2
Error frequency: 1.
Lost Count: 4
Mileage: 17732 km
Date: 2021.02.26
Time: 17:44:27

Supply voltage at terminal 30: 11.6 V.
Terminal 15: a...

Address 69: Trailer.
unavailable; unreachable

Hi,

Quote:

Address 69: Trailer. unavailable

First, I would recheck the wiring, paying particular attention to the CAN connection (twisted pair cable), ground, and power supply voltage.

As long as the trailer control unit is not accessible, it cannot do much.

If possible, clear all error codes first to remove any lingering fault records. Also, be aware that the on-board voltage may drop; it's best to perform diagnostics with a voltage of more than +12V, so using a charger is recommended.

Best regards, Rainer.

Good day.

At first glance, it seems to me that the coding wasn't properly implemented in the control units.

And the cables for the brake lights were incorrectly connected.

Let's check if the encoding was correctly implemented in the central electrical system. If something is wrong here, you usually encounter a large number of errors.

Did you perform a scan before installation, or at least check for any existing errors?

What errors reappear after the deletion?

If the original scan is available, reset the encoding and re-encode with sufficient voltage supply.

When coding, make sure the central locking system is completely unlocked!

What about the brake light bulbs? Are the cables connected incorrectly in the socket?

Make sure to compare the cables with the pins in the socket and check the fuses. Something isn't right here.

Did the retrofit kit include a parking assist control unit, or was the control unit already installed from the factory?


Best regards,