Er CB
LG Refrigerator
Severity: CriticalWhat Does This Error Mean?
The Er CB error means there is a communication failure between the main control board and one of the sub-boards (such as the display or inverter board). The boards cannot exchange data properly. This can affect temperatures, fans, and the display.
Affected Models
- LRMVS3006S
- LRFXS2503S
- LFXS26973S
- LRMVS3006D
- Most LG French door and side-by-side refrigerators
Common Causes
- Wiring harness between control boards has a loose or broken connector
- Power surge damaged one of the circuit boards
- Main control board has partially failed
- Display or inverter board has failed
- Internal electrical noise from a failing component disrupting board communication
How to Fix It
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Unplug the refrigerator from the wall for 10 full minutes.
A full power drain resets all control boards simultaneously and can clear temporary communication faults.
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Plug the refrigerator back in and wait 5 minutes for all boards to initialize.
The display may cycle through a startup sequence — this is normal.
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Check if the error clears and if the fridge is cooling normally.
If the error does not return within 24 hours, a power reset resolved a temporary glitch.
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Check that the refrigerator is plugged into a properly grounded outlet.
Power surges and faulty grounding can cause recurring board communication errors.
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If the error returns, contact a certified LG technician for board diagnostics.
Do not attempt to swap boards yourself without professional diagnosis — wrong replacements are expensive.
When to Call a Professional
A communication fault between boards is not a user-fixable issue. It requires professional diagnosis to determine which board has failed. Expect repair costs of $150–$400 depending on whether the main board, display board, or inverter board is at fault.
Frequently Asked Questions
Is the Er CB error serious?
Yes — if the boards cannot communicate, the fridge may not maintain correct temperatures. Monitor temperatures closely with a separate thermometer. If temperatures rise above safe levels, move food immediately and get an urgent repair.
Can a power surge cause the Er CB error?
Yes — power surges are a common cause of board communication failures. If you experienced a power outage or brownout before the error appeared, that is likely the cause. Using a surge protector for your refrigerator is strongly recommended.
How much does it cost to replace an LG refrigerator control board?
The main control board typically costs $80–$200 for the part. Display boards and inverter boards range from $40–$150. Labor adds $100–$200 depending on your location. A technician must diagnose which board failed before ordering parts.