Here are some secret codes of smartphone which will be a great help for you

##4636##	Display information about Phone, Battery, and Usage statistics
##7780##	Restting your phone to factory state-Only deletes application data and applications
27673855#	It’s a complete wiping of your mobile also it reinstalls the phones firmware
##34971539##	Shows completes information about the camera
##7594##	Changing the power button behavior-Enables direct power off once the code enabled
##273283255663282##*	For a quick backup of all your media files
##197328640##	Enabling test mode for service activity
##232339## OR ##526##	Wireless Lan Tests
##232338##	Displays Wi-Fi Mac-address
##1472365##	For a quick GPS test
##1575##	A Different type GPS test
##0283##	Packet Loopback test
##0##*	LCD display test
##0673## OR ##0289##	Audio test
##0842##	Vibration and Backlight test
##2663##	Displays touch-screen version
##2664##	Touch-Screen test
##0588##	Proximity sensor test
##3264##	Ram version
##232331##	Bluetooth test
##7262626##	Field test
##232337#*#	Displays Bluetooth device address
##8255##	For Google Talk service monitoring
##49862650468##*	PDA, Phone, Hardware, RF Call Date firmware info
##1234##	PDA and Phone firmware info
##1111##	FTA Software version
##2222##	FTA Hardware version
##44336##	Displays Build time and change list number
*#06#	Displsys IMEI number
##8351##	Enables voice dialing logging mode
##8350##	Disables voice dialing logging mode
##778 (+call)	Brings up epst menu