WT4870CW - LG Washing Machine Service Manual (repair manual). Page 31

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4-6. TROUBLESHOOTING WITH ERROR CODE
31
Trouble
IE
OE
dE
dL
FE
tE
PE
LE
No Power
1. Verify the valve is open and water is on. 
2.  Check the filter on inlet valve whether  
clogged with foreign material or not.
3. Check the connector of valve and RD6 on PCBA.
4. Check the testmode (Testmode 3)
5. Check the valve resistance. (0.8-1.2 kΩ)
1.  Check the test mode (Testmode 6)
2.  Check the connector of PCBA or pump or  
connection connector
3.  Check the connection from PCB to pump by tester
4.  Check the pump SPEC (resistance of the coil is  
10-20 Ω) and input voltage on working (120V±5%)
1.  Connect other doorlock switch and check the lid  
sensing by magnet
1. Check the doorlock switch trying locking
2. Check the balance of the lid.
1.  Check the Water level  
(1) Power on and run  
(2) Press the SPIN SPEED & DELAY WASH
2. Check the valve
1.  Check the connector of PCBA (YL2) or thermistor  
or connection connector
2.  Check the cutted connection from PCB to  
thermister by tester
1.  Check the Presure Sensor (21~23 Ω ±10%) and 
connection
2.  Check the Connector (BL6)
1.  Check the connector of PCBA (YL3, BL6) or  
motor connector or connection connector
2. Check the magnet for Rotor
3.  Check the Rotor Resistance (YL3) 5 to 15 Ω  
(U-V, V-W, W-V :U=1, V=2, W=3)
1. Check the fuse for noise filter and PCBA by tester
2.  Check the IPM  
-.  Check the Short between top switch  
Heatsink and YL3 pin by Tester
Check
counterplan
1. Turn the tap on.
2. Clean or replace the filter
3. Reconnect or repair the connector
4. Replace the PCBA
5. Replace the inlet valve assembly.
1. Replace the PCBA
2. Reconnect or repair the connector
3. Replace harness
4. Replace pump
1. Replace the doorlock switch or PCBA
1.  If trying, replace the doorlock switch.  
Or not trying replace the PCBA
2. Replace the door or set the balance
1.  If segment is displayed under 10,  
replace the PCBA
2. Replace the valve
1. Reconnect or repair the connector
2. Replace harness
1. Reconnect or repair the connector
1. Reconnect or repair the connector
2. Replace the rotor.
3. Replace the stator.
1.  If the beep sounds, the fuse is OK.  
If no beep, change the noise filter, 
including the fuse. 
2. If beep sound, replace the PCBA.
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