How do I fix error code E Sd on a LG refrigerators?

1. undefined: Check loose connections at Sub PCB and main PCB connectors. 2. undefined: Reconnect any loose connectors. 3. undefined: Measure voltage at Sub CON1 8th Pin ~ 33rd Pin. Should be Not 0 or 5V. If 0 or 5V: check Sub PCB connection; if connection OK, replace Sub PCB. 4. undefined: Measure voltage at Sub CON1 10th Pin ~ 33rd Pin. Should be Not 0 or 5V. If 0 or 5V: check Sub PCB connection; if connection OK, replace Sub PCB. 5. undefined: Measure voltage at Main CON3 1st Pin ~ 15th Pin. Should be Not 0 or 5V. If 0 or 5V: check Display PCB connection (loose) or replace Display PCB. 6. undefined: Measure voltage at Main CON3 3rd Pin ~ 15th Pin. Should be Not 0 or 5V. If 0 or 5V: check Display PCB connection or replace Display PCB. 7. undefined: If all voltages pass: explain to customer.

LG Refrigerators

Error Code E Sd

Sub PCB communication error

Moderate

Address soon - your appliance may not work properly

How to Fix

1
Check loose connections at Sub PCB and main PCB connectors.
2
Reconnect any loose connectors.
3
Measure voltage at Sub CON1 8th Pin ~ 33rd Pin. Should be Not 0 or 5V. If 0 or 5V: check Sub PCB connection; if connection OK, replace Sub PCB.
4
Measure voltage at Sub CON1 10th Pin ~ 33rd Pin. Should be Not 0 or 5V. If 0 or 5V: check Sub PCB connection; if connection OK, replace Sub PCB.
5
Measure voltage at Main CON3 1st Pin ~ 15th Pin. Should be Not 0 or 5V. If 0 or 5V: check Display PCB connection (loose) or replace Display PCB.
6
Measure voltage at Main CON3 3rd Pin ~ 15th Pin. Should be Not 0 or 5V. If 0 or 5V: check Display PCB connection or replace Display PCB.
7
If all voltages pass: explain to customer.