1). *#*#4636#*#*
This code is used to display cell phone, battery, usage statistics and WiFi information

2). *#*#7780#*#*
Restore to factory settings, do not delete preinstalled apps and SD card files

3). *2767*3855#
Restore to factory settings; delete all files in SD card

4). *#*#197328640#*#*
Launch service mode to test and change certain settings

5). *#*#232339#*#* or *#*#526#*#* or *#*#528#*#*
Test WiFi

6). *#*#232338#*#*
Display WiFi MAC address

7). *#*#1472365#*#*
GPS test

8). *#*#1575#*#*
Other GPS test

9). *#*#232331#*#*
Bluetooth test

10). *#*#232337#*#
Display Bluetooth physic address

11). *#*#8255#*#*
Start Gtalk monitoring

12). *#*#4986*2650468#*#*
PDA, Phone, H/W, RFCallDate

13). *#*#1234#*#*
PDA and Phone

14). *#*#1111#*#*
FTA SW version

15). *#*#2222#*#*
FTA HW version

16). *#*#44336#*#*
PDA, Phone, csc, build Time, anzhi.name, changelist number

17). *#*#0283#*#*
Packet Loopback

18). *#*#0*#*#*
LCD test

19). *#*#0673#*#* or *#*#0289#*#*
Melody test

20). *#*#0842#*#*
Device test such as viberation and lightness

21). *#*#2663#*#*
Display touchscreen version

22). *#*#2664#*#*
Touchscreen test

23). *#*#0588#*#*
Distance sensor test

24). *#*#3264#*#*
Display memory version

Note:: May be some secrete codes vary to your cell because the Android secret codes vary for some mobiles.