Peugeot 407 handsfree microphone failure

Sounds familiar! Had a similar issue with my old Volvo V70, though that was petrol. The Bluetooth module failed. Could hear people fine, but they couldn't hear me – like talking through a pillow filled with cotton wool. Was there any weird volume control stuff happening beforehand? Or crazy ambient noise when you were on a call?

Volume control was acting a bit weird, now that you mention it. Sometimes it would jump up and down randomly. Ambient noise... yeah, people did complain about hearing a lot of background noise, even when I was in a quiet place. You reckon it's the same thing then?

Yep, sounds like the infotainment system's failing, specifically the Bluetooth module responsible for audio input. The random volume spikes and ambient noise complaints confirm it for me. Best bet is to take it to a workshop; they'll confirm the fault and quote you for a replacement. It isn't cheap, but at least you'll be able to make calls again!

Cheers for the advice! Booked it in at the shop. Turns out you were spot on. Infotainment system defective and they are quoting 815€ for the repair. Ouch, but at least it'll be fixed. Thanks again!