LG -E405 Service Manual page 162

11. HIDDEN MENU
GPS BT Wifi Test
GPS(RF) test : CNO is some value : OK
Bluetooth Scanning is PASS : OK
WiFi Scanning is PASS : OK
Sound Loopback Test
"Look Back On" is test mode on
"Look Back OFF" is test mode off
FM Radio Test
87.5 Mhz is scanned automatically
-> Connect ear-jack
-> Touch "FM Radio Off" icon
LGE Internal Use Only - 162 - Copyright © 2012 LG Electronics. Inc. All right reserved.
Only for training and service purposes