Share your experience!
Hi, the internal speacker don't seem to work during call, when I use external speacker I can hear interlocutor but not with the internal.
Diagnostic fonction fail too.
This is the second time I have problem with my sony, I'm beginning to believe that they have reliability problems. 
Hi @fred-kilow,
I'm so sorry to hear about that. 
As @uliwooly wrote, it does sound like it's related to hardware and not software.
Just to be sure of this, I'd recommend performing a software repair using Xperia Companion.
A software repair will remove all data stored on the internal storage so creating a backup with Xperia Companion is advised, prior to starting with the repair.
If there is no change, please get in contact with your Local support team and they will arrange a repair for you.
I understand that is never fun to have to send your phone to service, especially a second time.
Let us know how it went!