Screen Freezing when getting busy tone.

[anbucha13]

My girlfriend recently got an Xperia SP and today while making a phone call the receipiant was engaged so got a busy tone. The screen would go black and all buttons would be unresponsive, this happened several times. Its fine making calls otherwise, just when she gets a busy tone.

Can anyone help please?

[Alexander1]

Press *#*#3738423#*#* to get into the service menu. Go to service tests > proximity switch and test if the proximity switch between on/off when you put your hand over the the top of the display.

If it says "ON" all the time you should first of all remove any 3rd party screen protector you have put on the phone display. Maybe there been some dirt or dust that cover the sensor.

[eprat]

I have a 1 week old SP and have exactly this problem. The proximity sensor is always on. I do not have any screen protector or 3rd party screen-saver apps. Does this mean that it's a hardware fault and I need to have my phone replaced? Or is it a software fault, and I should wait for Sony to correct this?

I am on Android version 4.1.2 build number 12.0.A.1.257

@Alexander: The keypad sequence is actually: *#*#7378423#*#*