Screen goes blank when calling - cannot use touchpad

[Android Central Question]

I have a Sony Xperia. When I dial a number, the screen goes blank and unresponsive from the moment dialling starts until the caller puts the phone down the other end. This means I for instance cannot get access to my touchpad to enter any number choice options, so it is not possible to have a call centre conversation, order a taxi etc.

This happens whether the phone is in its case or not, and whether I have it held to my ear or not.

 

[belodion]

Check that there are no app or system updates pending. If not, try clearing the cached data in Settings, Storage. If no go, try a Cache Partition wipe. If still no go, try Safe Mode.
Get back to us if you still have trouble.

 

[B. Diddy]

Welcome to Android Central! It sounds like an issue with the proximity sensor, which can be caused by anything that's overlying it. The most common culprit is a poorly fitting screen protector -- do you have one on? Otherwise, make sure the area over the sensor is completely clean. If the problem still occurs, then the sensor may be faulty.