FM Radio (Antenna?) dead

[Lancisti]

Hi!

As a new member from Finland, I was reviewing old topics but couldn't find exact solution for my problem.

Already more than a year back the radio reception kind of stopped on my 2005 C6 Avant and only noise can be heard from the speakers. Tuner won't find any stations. however the CD-player is working normally as is everything else. Had the codes read and found something related to antenna short circuit:

Address 56: Radio Labels: Redir Fail!
Part No SW: 4F0 910 730 T HW: 4F0 035 729 B
Component: MMI Cockpit H55 0050
Revision: C51500BE Serial number: AUZ6Z3E89752S3
Coding: 0124101
Shop #: WSC 02325 785 00200
VCID: 326BCFB6AD79B8D657-8066

2 Faults Found:
00856 - Radio Antenna
007 - Short to Ground - Intermittent
Freeze Frame:
Fault Status: 00100111
Fault Priority: 5
Fault Frequency: 5
Reset counter: 103
Mileage: 214468 km
Time Indication: 0
Date: 2017.12.29
Time: 16:46:55

00856 - Radio Antenna
011 - Open Circuit
Freeze Frame:
Fault Status: 01101011
Fault Priority: 5
Fault Frequency: 2
Reset counter: 67
Mileage: 213996 km
Time Indication: 0
Date: 2017.12.21
Time: 14:20:38

When trying to locate the fault, found also the broken rear washer pipe on the rear which has leaked not sure how long. Device (Sound Amplifier Basic, 4F0910223B) on the rear left corner didn't look wet, but of course the water may have entered in it.

Found also burnt 5A fuse from the left side fuse box on the dash, (Aerial amplifier, I think) but replacing that didn't help.

Have checked the antenna cables, but those seems to be ok. Already replaced the amplifier close to left side rear window antenna, but no luck. Is there anything else to check?


It looks like it is a lot of knowledge with these cars here so i really hope someone could help me with this issue. My wife is mainly driving this car and starts to get really ****** off with this on long drives. What would be the best way to continue getting the radio back?

Thanks,

Petteri

[Gunnark100]

Did you checked cabels/antennas/ant amplifiers as per audi diagrams or just what you could see(as this antenna system is pain in...)?


Edit: Check your "message box"!

[Lancisti]

Unfortunately I don't have Audi diagram available. Just measured the condition of the cables as far as possible with multimeter.

Yeap, the system is the pain in there!

-Petteri

[zit501]

I had very poor reception on my radio, also wasn't picking up many, if any, stations. It turned out that the K-box radio module had gotten wet during its tenure with the previous owner and partially killed the radio circuit. It was also reporting fault for open circuit on the antenna. I fixed it by just getting a new radio module. They can be found rather cheap on eBay and they don't have component protection so you can just swap it. The water damage inside was obvious when I opened it up.

I know that there was a recall on the C6 Avant to retrofit a fix for the rear windscreen washer pipe, which would crack and break where it went through the left hinge. This would leak and potentially damage the infotainment modules on the left side of the boot. I think this happened but Audi didn't replace the modules. I know I have the pipe fix in my car.

[Lancisti]

Yesterday once again disassembled the boot and checked the rear heater and antenna amplifiers. No luck in there. Then I replaced the "new" antenna amplifier with the original, and what happened, radio is alive again! I thought I tried this already before, but then it wasn't working. It must be before I replaced the burnt fuse. Confusing.

So according to my analysis, it has been the fuse all the time, but I didn't check that at the beginning. Amateur mistake, but now it is working again. What a relief!

-Petteri

[zit501]

Great stuff!