1. Remove USB Cable
2. Dialer -> 5689#*740*
You can run a device test from the hidden menu to find out if there are some hardware defects when you experience any issues with your handset.
2.Select Device Test
3.Select ‘All Auto Test – Full’
Please notes that it is dangerous to change any settings in the hidden menu, Please do not change the default settings if you do not know what it is exactly.