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

1. undefined: Check all connectors between main PCB and sub PCB for loose or disconnected wiring. Reconnect as needed. 2. undefined: Measure voltage at Sub CON1 8th Pin to 33rd Pin. Expected: not 0 or 5 V (oscillating). If static 0 or 5, check Sub PCB connection — replace Sub PCB if connection is good. 3. undefined: Measure voltage at Sub CON1 10th Pin to 33rd Pin. Expected: not 0 or 5 V. If static, check Sub PCB connection — replace Sub PCB if connection is good. 4. undefined: Measure voltage at Main CON3 1st Pin to 15th Pin. Expected: not 0 or 5 V. If static, check Display PCB connection — replace Display PCB if connection is good. 5. undefined: Measure voltage at Main CON3 3rd Pin to 15th Pin. Expected: not 0 or 5 V. If static, check Display PCB connection — replace Display PCB if connection is good. 6. undefined: If all checks pass, explain normal operation to customer.

LG Refrigerators

Error Code E Sd

Sub PCB Communication Error — Main MICOM to Sub MICOM

Moderate

Address soon - your appliance may not work properly

How to Fix

1
Check all connectors between main PCB and sub PCB for loose or disconnected wiring. Reconnect as needed.
2
Measure voltage at Sub CON1 8th Pin to 33rd Pin. Expected: not 0 or 5 V (oscillating). If static 0 or 5, check Sub PCB connection — replace Sub PCB if connection is good.
3
Measure voltage at Sub CON1 10th Pin to 33rd Pin. Expected: not 0 or 5 V. If static, check Sub PCB connection — replace Sub PCB if connection is good.
4
Measure voltage at Main CON3 1st Pin to 15th Pin. Expected: not 0 or 5 V. If static, check Display PCB connection — replace Display PCB if connection is good.
5
Measure voltage at Main CON3 3rd Pin to 15th Pin. Expected: not 0 or 5 V. If static, check Display PCB connection — replace Display PCB if connection is good.
6
If all checks pass, explain normal operation to customer.