How to re-calibrate your proximity sensor
Sometimes manufacturers make screen protectors that cover your entire screen, yes even your camera and proximity sensor. If you’re lucky, you won’t notice anything different but if you’re not, you will experience a black screen upon answering or making a call. This happens because the proximity sensor is being covered just enough by your screen protector and is tricking your proximity sensor into thinking you have your phone held up against your face. The proximity sensor is responsible to turning your screen off when in a call to save battery and so that you won’t accidentally hang up by touching your phone with your cheek.
There are many different versions and models running Android, this is an example with the LG G4.
This issue can be solved by re-calibration proximity sensor, you still can use screen protector with sensor covered up.
Mine is H815.
Follow steps below to re-calibrate proximity sensor(must with the glass protector is installed and which is sensor covered up)
1. TYPE “277634#*#” in phone dialer. Hidden Menu screen will show up.
2. Select “Device Test”->”MT”, it will show “system will be restarted”, then choose OK.
3. After reboot, GENESIS MiniOS 3.1 screen will show up, press “individual item+power” while power button is pressed.
4. Next, find “sensor test”, enter it(do not block the proximity sensor), the proximity sensor will be automatically calibrated. Then block proximity sensor two times to exit.
5. Find “Back to the MainList”, enter.
6. Press “Normal boot+power” while power butten is pressed to reboot system, done.
Now the problem should be solved.