Dead Audio System After Shop Repair in Audi S4

Had a similar audio system failure in my 2009 Audi A4 2.0T after routine maintenance. The complete audio loss and display error typically points to either a damaged amplifier or disconnected wiring harness. In my case, techs found the main wiring harness was damaged during previous work. The bundle of wires behind the head unit had been pinched when reinstalling components, causing several connections to fail. This affected both the audio output and display functionality. Common troubleshooting steps before visiting a shop: Check all fuses related to audio system, Verify head unit gets power, Test volume control and source inputs, Listen for any static noise when adjusting settings, Inspect visible wiring for obvious damage This usually indicates a serious electrical issue requiring professional diagnosis. The repair often involves: Full diagnostic scan, Removal of head unit, Inspection of wiring harness, Testing amplifier function, Checking all car speakers individually Recommend having the original repair shop inspect it since the issue started after their work. Document when the audio quality problems began and what maintenance was performed. Keep all paperwork from previous repairs to show the timeline.

Thanks for sharing your experience. Sounds exactly like the issue I had, total silence from the head unit after routine work. The faulty wiring behind my dashboard controls was also pinched during reassembly. A full inspection revealed damaged Bluetooth connections too. Would you mind sharing what the final repair cost was? Also curious if any other electrical gremlins popped up afterwards, since sometimes these audio system problems can be linked to other issues.

Since having the mechanic inspect and repair the faulty wiring in my Audi A4, the sound system has been working flawlessly. The total repair cost came to 725 Euro, which covered diagnosing the damaged wiring harness and fixing the defective display unit. The Bluetooth problem and audio quality issues were completely resolved once they repaired the pinched wires. No other electrical problems have surfaced in the months since the repair. The static noise disappeared and all car speakers are functioning properly now. The key was having a thorough diagnostic scan done to identify all the damaged connections. While the initial cost seemed high, preventing further electrical damage made it worthwhile. The repair shop also checked surrounding components to ensure no other wiring was compromised during the original maintenance work.

Thanks for the input. Took my car to a different mechanic this time. They found multiple pinched wires behind the dashboard controls, just like you described. My faulty wiring was causing both the audio system failure and some secondary electrical issues. The repair took about 4 hours. Total cost was 680 Euro including parts and labor. They had to remove the entire head unit to access and replace the damaged wiring harness. The audio quality is perfect now, no static noise, all car speakers working great, and even the Bluetooth connects better than before. Really glad I asked here first. Having some knowledge about the likely cause helped me explain the problem better to the new mechanic. They also found and fixed a loose ground wire while they were in there, which might have caused issues later.