Share your experience!
i'm living this boring problem despite system repair...
sony must make a new uptade for choose this problem.
otherwise, lost of stamina mod is big sacrifice.
i'm 37 years old n z3c is the best phone i use until now; solve sony, solve 
In previous lollipop version caller, I can double click power button to wake up screen, and keep it on when screen is facing up.
But in new marshmallow caller, there is no workaround with faulty proximity sensor. There is no way wake up screen and keep it on during call. I already reverse to lollipop, and I hope sony can address this issue. All other sensor can be disabled, there should be a choice to disable proximity sensor, at least in caller app.
If your phone has a faulty proximity sensor, contact your Local support to get it inspected.
I had the same issue, i washed my phone under the tap ans suprisingly it worked
I have the same issue with my Xperia Z5,
I tried everything, and I gave up.
I'll never ever gonna buy a Sony smartphone again.
Totally a disappointment.
I should have stick with my iphone...
I had this problem too, and when I removed the screen protector just now, it started working properly again.
I am also facing same problem.
I am haivng xperia z3.
display goes off while dialing. It will be back only when other person over the phone hang up the call.
I bought a sony xperia z3 in 2015 nov. Suddenly the touch screen doesn't work and i sumitted the phone to sony service. They checked and couldnot repair and replacd with a new set. That set also got screen problem. It goes black but it works. Again submitted to sony and they chrged Rs 900 and returned. And after 3 days the same problem returned. And now sony asks Rs13000.
What sony is thinking. we have bought a phone for 45000 and after 16 months we have to pay them 13000?
it seems a daytime robbery.. will anyone in sony answer?
Thanks... I have removed the protection screen (Glass type) and it is working