Peugeot 607 Audio System Failure

It sounds like you've already covered the basics. Intermittent audio issues in older cars can often be tricky. When you say 'error code', do you know what the specific code is? Also, have you noticed any crackling sounds from the speakers before it completely failed? Sometimes, that can indicate a failing amplifier or speaker issue. Dashboard controls and volume control still light up as normal?

I didn't record the specific error code, but I can retrieve it. I didn't observe any unusual noises prior to the complete failure. The dashboard controls and volume control do illuminate and appear to function normally, although there is no corresponding change in audio output. Could a faulty display really cause a complete audio system shutdown, even if the display itself seems functional?

Okay, the fact that the controls light up normally is interesting. It does sound like the display itself might be the problem, especially if the audio system is integrated through it. It's hard to say for sure without proper diagnostics, and a faulty display can sometimes cause a complete system failure like you are experiencing. Given the age of the car, it might be best to have a workshop take a look. They can properly diagnose the fault.

Based on your recommendation, and further research, I decided to take my vehicle to a reputable workshop. They confirmed that the display unit was indeed defective and needed replacement. The repair cost amounted to 725€, which was somewhat disheartening, but at least the audio system is now functioning correctly.