What CO means (lg co error)
An lg co error (Er CO) on an LG refrigerator is a communication fault — the main control board and the display board have lost their link. Cooling may continue, but the control raises CO because it cannot reliably exchange data with the display, which usually needs the connection or a board checked.
Symptoms to look for
The signs below help confirm you are dealing with this condition rather than a different fault on your LG Refrigerator. You may see one of them or several together, and they can build up gradually or appear suddenly after a power event, a long door opening, or recent service.
- The display shows “CO” or “Er CO”
- The display behaves erratically or goes blank
- Settings may not respond
- Cooling may still run normally
Common causes
Several different faults can produce these symptoms. Working through the most likely causes in order helps separate a quick, owner-level check from a problem that needs trained service and the correct LG parts.
- Loose interconnect harness — the board-to-board link is poor
- Display board fault — the display cannot communicate
- Main control fault — the main board cannot communicate
- Moisture or corrosion — a connector has degraded
Troubleshooting steps you can try
Work through these checks in order before calling for service. Stop wherever you are unsure, or where high-voltage parts, gas, the sealed refrigeration system, or a heat-pump compressor are involved, and hand the rest to a qualified technician.
- Power the fridge off at the breaker for several minutes, then restore.
- Note whether cooling continues normally despite the display fault.
- Avoid relying on the display settings until the comms are stable.
- If CO persists, leave it for service to test the board interconnect.
Parts a technician may replace
Depending on what the diagnosis shows, a technician may inspect, test, or replace the main control board, display board, and interconnect harness. The correct part for your LG Refrigerator is matched from the model and serial number, and genuine LG components are fitted rather than generic substitutes so that performance, safety, and the appliance’s long working life are all protected. Confirming the failed part before ordering avoids replacing more than the fault actually requires.
When to call a technician
CO needs a technician to test the main and display boards and their interconnect harness and replace the failed part. When the fix calls for trained service, book a visit through our scheduling page and an experienced, qualified technician will diagnose and repair it. For manufacturer documentation and model lookup, see the manufacturer at lg.com/us.
Prevention and care
Regular care keeps this condition from returning on your LG Refrigerator. Keep filters, vents, and the condenser or exhaust path clean, avoid overloading or blocking airflow, check that doors and seals close cleanly, and follow the LG maintenance guidance for your model. Because this unit relies on electronic control, protect it with a stable, correctly rated power supply and have any built-in or laundry installation done to LG specification so the control never sees an out-of-range condition. If a code appears, note exactly what was shown before you reset the appliance — that record helps the technician reach an accurate diagnosis and avoid replacing parts unnecessarily.
Related help and LG resources
Browse other LG Refrigerator diagnostics, read about professional LG Refrigerator repair, look up your unit in the LG models reference, or the related 67 door-gap fault, or schedule a service visit. For LG manufacturer documentation and model lookup, visit the manufacturer at lg.com/us.
