RNS-D: GALA & Navigation Issues in Audi A4 8E

Hello,

I've been reading here for over 2 years and have already found many valuable tips. Thank you for that. Today, I also need to post a problem. I've retired my good old 35i RNS-D (BNS 4.2), factory-installed, comes standard with TMC tuner (nothing modified or added).
Error: GALA is no longer working; when navigation announcements are made, the radio/CD playback is no longer muted.

So far, the following has been reviewed:
- Checked the device settings (volume settings) to make sure nothing has been changed. => Everything is as it should be.
- NAVI system expanded, fuse and seat connector contacts checked => everything is OK.
- NAVI disconnected (sometimes these things can get 'stuck' anyway) => Error still present.
- Read the error memory of the AI system, result: (sporadically) 'No communication with the radio'.
- Error memory of the AI system cleared, driven one round, re-read: same entry as above (2 times).

Okay, I'm quite at a loss now. Everything else seems to be working fine - the MFL controls are working: OK, the radio/CD/navigation display in the FIS is working: OK. So, the instrument cluster should be able to communicate with the radio. A failure of the GALA signal should definitely manifest itself in some other way (e.g., in navigation mode).
As far as I know, these older navigation systems don't have their own CAN bus connection and instead use the TMC tuner to achieve this.

Unfortunately, I'm not as knowledgeable about electronics as I am about tools. I'm hoping someone can give me a tip on where I might be able to focus my troubleshooting efforts.

Sure, here's the translation:

'Thank you in advance.'

Christian.

"It's likely a fault in the wiring harness between the radio and the navigation system. The navigation system already uses CAN (Controller Area Network). It seems you have a broken wire. You can only measure the wires between the radio and the navigation system to pinpoint the location of the fault."

How long have you had the car? Less than 6 months? Then take it to the dealer and let them get their hands dirty.

Hmm, in my car, the radio and navigation system are integrated into a single unit (a double-DIN device). Are you thinking there might be a broken wire inside the device?

Christian.

Your navigation system is located in the back of the trunk. It's also the device where you insert the CDs.

How long have you had the car, and is it from a dealer?

I'm having a little trouble following right now. I've attached a picture of the installed navigation system.
I will insert the navigation CD into the slot located to the right of the DISPLAY button.

Den Wagen habe ich seit November letzten Jahres und ich habe ihn bei einem gewerbl. Dealers acquired.

Christian.

'Could you please post a complete self-diagnosis scan of the car, so that we can see some of the part numbers of the installed systems and perhaps narrow down the problem?'

If you purchased it from a dealer, take it back there and have them repair it. They still need to prove that the defect didn't exist at the time of purchase.