Originally Posted by onewaylife4all
No, it won't turn on if the phone if OFF. I'm referring to it "waking up". It will wake up simply by holding the phone at a certain angle and distance away from the body.
Are you using a custom Rom/kernel? if so, try installing a new Rom
If that happens to be a hardware problem, It could be more related to the power button than the P.sensor
Most common issues related to the sensor is that screen stays off. Eventually, a screen protector can produce that, but not in your case.
The proximity sensor won't notice the angle you tilt the phone at (compass sensor does). It needs to detect something in front of it closer than +-1 inch to act up and should
turn off the screen when in a phone call. There's no much reason to turn on screen because it is not its function and much less if not phone call is happening.
Maybe the USB port is dirty and thinks you plugged a charger
or power ribbon/connector is loose inside, if any.