How can I enable field test mode on Samsung Galaxy S3? I have a Samsung Galaxy S3. Are there any codes to enable field test mode, like band selection? Has someone managed to enable such an option?
*#*#7262626#*#* – Perform a field test
*#2263# - If previous doesn't work.

Sadly, Samsung used to provide field test display by entering codes in keypad. However, from Galaxy S3 onward, the service mode *#*#197328640#*#* was disabled. Only *#0011# is still available.  The worst is that even the Android default testing info *#*#4636#*#* was disabled as well.

And just because this looked very sparse, here's a big list!

For IMEI Number: *#06#  
For RAM Memory version: *#*#3264#*#*
For FTA SW version: *#\*#1111#*#*
For FTA HW version: *#*#2222#*#*
For Touchscreen version: *#*#2663#*#*
To test Bluetooth: *#*#232331#*#*
To display Bluetooth Physic Address: #*#232337#*#
To test secret GPS: *#*#1472365#*#*
To test other GPS:  *#*#1575#*#*
To test WiFi/Wireless LAN of phone: *#*#232339#*#* or *#*#528#*#* or *#*#526#*#*
To display Wi-Fi MAC Address: *#*#232338#*#*
To test Vibration and Back-light of device: *#*#0842#*#*
To test Proximity/Distance Sensor: *#*#0588#*#*
To test Touchscreen: *#*#2663#*#*
For Audio Test: *#*#0289#*#* or *#*#0673#*#*
To launch Service Mode: *#*#197328640#*#*
Hidden Service Menu (Motorola Droid): ##7764726
Field Test: *#*#7262626#*#*
To format the phone: *2767*3855#
To Restore Factory Settings: *#*#7780#*#*
To create Immediate backup of your multimedia files: *#*#273282*255*663282*#*#*
To display Phone Information: *#*#4636#*#*
To get detailed Camera Information: *#*#34971539#*#*
For Software &amp; Hardware Information: *#12580*369#
To display HSDPA/HSUPA Control Menu: *#301279#
To start GTalk Monitoring: *#*#8255#*#*
To get PDA, Phone, H/W and RF Call Date: *#*#4986*2650468#*#*
Displays Build Time and Change List number: *#*#44336#*#*
Packet Loopback Test: *#*#0283#*#*
LCD  Display Test: *#*#0*#*#*
Enter Service Menu (on New Phones): *#0*#
Diagnostic Configuration: *#9090#
USB Logging Control: *#872564#
System Dump Mode: *#9900#
View Phone Lock Status: *#7465625#
Executes Emergency Dial Screen to unlock PUK Code: **05**#
Enables Voice Dialing Logging Mode: *#*#8351#*#*
Disables Voice Dialing Logging Mode: *#*#8350#*#*
Change behavior of Power button: *#*#7594#*#*