Sdtexas4

Long story short. The Fuse has been disconnected. Picked up my A4 from the garage today and the reconnected the stereo. I no longer have sound. It has been disconnected for about a year or so. The stereo and all the functions work, but plays so no sound. I checked all fuses. No idea where to start. Thoughts?

SMac770

A scan for DTCs to see what the car says would be a start.
I imagine if the CP had kicked in, there would be some visual to that on one of the displays. But the scan should should say (and I mean a good scan like VCDS, not a ODB generic scan like AutoZone).
The same is true for all audio sources? Bluetooth hands free too?

Sdtexas4

CP? Sorry I’m handicapped on vehicles.

Yeah all audio sources and Bluetooth has well. Even tested a call. Able to be heard but no sound.

SMac770

component protection, I've not had the issue but iirc, working but no audio is an exhibit of the component theft protection having kicked in. Of course, it could also be a blown amp, broken volume ****, etc. :-)

A scan is really the correct start point for any issue, though. Only if it doesn't point you with some guidance do you then go to random guessing.

Is this the MMI system? Or the concert/symphony system? Is it the basic speaker system (8 speaker for non-MMI, 10 speaker for MMI (adds sub & center dash)) , or the B&O system (14 speaker)? All four combinations vary in how the amp is implemented.

Sdtexas4

Its the Audi Concert. I believe its the 8 speaker system.

SMac770

So you have the CAN system (Concert/Symphony with the controls on the dash like a normal radio) rather than the MMI system (controls around the gear shifter).
You still have the outboard "digital sound system control module J525" (ie, the amp) unit in the back left of the trunk (as you already posted a pic of on the audizine thread).
This J525 differs depending on if you have CAN or MMI and if you have standard or B&O. As you have CAN and non-B&O, your picture matches the expectation (a single 32-pin connector).
The CAN non-B&O J525 does support 10 speakers, though you may or may not actually have a center channel and subwoofer in your particular car.

In MMI, the sound signals from the radio are sent over the optical MOST bus, and the "radio" actually sits right below the amp in that back left of the trunk.
In CAN, the "radio" is actually in the dash, and the low level signals are sent over normal wires, like a normal old school stereo setup.
So there's the question of if the radio is sending any audio to the amp, vs is the amp working.
If you know how to backprobe the connectors on the 32-pin plug, you could check pins 26 (front left +) and 31 (front left -) for an AC voltage presence that varies with the volume.
(pins 27 and 32 are the two on the end of the plug opposite the end with the two large wires (which are 12v and ground), 26 and 31 are the next row in from that end).
The pins for the output of the amp to the front left speaker are 4 and 16.

Still, all of this is what you would do after you have a full scan in hand to know there's not already a known issue to be resolved, like component protection kicked in.