WM3431HS - LG Washing Machine Service Manual (repair manual). Page 24

AC120V

Replace the

SENSOR SWITCH

ASSEMBLY.

Replace the MAIN PWB
ASSEMBLY

Repair the DRAIN HOSE
ASSEMBLY.

Remove foreign material.

Reconnect or repair the
connector

Repair the DRAIN PUMP
ASSEMBLY.

Repair the MAIN PWB
ASSEMBLY.

When pressing Wash/Rinse and Spin Speed at
the same time after draining, is the water level
frequency 255?
When pressing and Spin Speed buttons
at the same time while washing, is the water level
frequency between 230 - 243 ?

Check the voltage between two pins while
pressing the POWER button. Is the voltage 
120 V AC?

Is the drain hose twisted or frozen?

Is the impeller of the drain pump clogged?

Is the connector disconnected  or disassembled.

Is the resistance of the drain pump coil too high or

low? (resistance of the coil is 10-20 Ω)

When checking voltage between connectors

during spin, is the voltage 120 V AC as in the

figure?