What does error code CO mean on a LG refrigerator?

Communication error. The main board and the display aren't communicating.

Can I fix LG code CO myself?

Start with these safe checks: Unplug the refrigerator for 60 seconds and plug it into a wall outlet directly, not a power strip. If CO returns, request service.

When should I call a technician for code CO?

If CO returns, request service. Don't open the sealed refrigerant system, cut or braze lines, or add refrigerant. That needs an EPA-certified technician. Turn power off at the breaker or disconnect before opening any panel, and leave capacitors, compressors and control boards to a pro: they can hold a dangerous charge even with the power off.

LG Refrigerator Error Code CO / Er CO / E CO: Communication error

What CO means

The main board and the display aren't communicating.

Also shown as: Er CO, E CO, depending on the model.

Likely causes

Loose connection
Board fault

Safe first checks

Unplug the refrigerator for 60 seconds and plug it into a wall outlet directly, not a power strip.

When to stop

If CO returns, request service.

Checked against: LG USA Support: LG Refrigerator digital and analog error codes. Codes can differ by model and year, so confirm with your owner's manual.