LG KF600w Service Manual page 108

Checking Flow: Headset detect problem
1
YES
Check the voltage at pin4 of
CON401 Whether its range is
1.65~2.1V
YES
Check
EAR_JACK_SENSE/ is low?
YES
4
Checking Flow: Headset detect problem
Check the soldering of CON401
NO
Resolder CON401 with heat gun
NO
YES
Redownload S/W
Replace CON401
NO