Peugeot 406 audio system failure

Sorry to hear about your 406. I've got one too, though I'm not sure of the year, and I had a similar issue once. Turned out to be a bad connection in the wiring harness behind the head unit. Did you check those connections?

Thanks, I didn't think of that. Can you tell me more about the bad connection you had? Loose wire, corrosion, something else?

I found a ground wire partially disconnected because of corrosion. Cleaning it helped a bit, but the problem was still there. Eventually, I found the bass speaker was faulty and needed replacing. Maybe a workshop visit is best, just in case.

Thanks for the help. I took your advice and saw a mechanic. The bass speaker was the problem, and it cost 280€ to fix. Appreciate you sharing your experience!