On the covered LG refrigerator, CO, Er CO means communication error: LG says the CO code indicates a communication error between the main board and the display. LG separately lists C1 as a communication error between the dispenser and the display. First, record whether the display or controls work intermittently.
Differential
Likely causes of “LG refrigerator code CO, Er CO”, and how to tell them apart
- 1
A communication error between the main board and the display
What separates it CO or Er CO shows and the panel is unresponsive
How to confirm LG says the CO code indicates a communication error between the main board and the display
- 2
A loose display or wiring connector
What separates it CO appears after the panel or door was bumped, or the display flickers before it fails
How to confirm Only a technician should reseat it; note when the display flickers and give that to them
- 3
A glitch left by a power surge
What separates it CO appeared once after a storm or an outage and the food is still cold
How to confirm Unplug the refrigerator for a few minutes, restore power and see whether CO returns
Before you touch a setting
Record this first — changing settings destroys the evidence
- The exact characters shown on the display: CO or Er CO
- Note whether the panel responds before you start troubleshooting
- Whether it followed a power surge
Try in this order
0 of 10 completedWhat to do first
ReversibleRecord whether the display or controls work intermittently.
Correct only the documented fault domain
ReversibleLG's page says to request service for the codes that indicate a malfunction, and that if the issue continues you should contact LG Customer Support.
Check the food temperature
ReversibleCheck whether the compartments are still cold, since the cooling may continue even if the display fails.
Request service
ReversibleIf CO returns, request service.
Check the food is still cold
ReversibleFeel the food and the air in both sections; if both stay cold the code is a display link problem and not a cooling failure, which tells service how urgent it is.
Note which controls respond
ReversibleWrite down whether the display or the controls work intermittently, which helps a technician decide between the display and the main board.
Unplug the refrigerator for five minutes
ReversibleUnplug it for about five minutes, then plug it back in and see whether the code clears.
Unplug for five minutes
ReversibleUnplug the refrigerator, wait five minutes and plug it back in. This clears a one-off communication fault.
Check for a loose connection
ReversibleIf the refrigerator was recently moved, look for a loose harness behind the panel, but do not open the panel yourself.
Protect the food
ReversibleKeep the doors closed and use a cooler if the display stays blank.
Model-specific
What is true of this model and not of its siblings
- Displayed as
- CO, Er CO.
- Parts named
- Main board; display.
Evidence ledger
Sources behind this answer
Where the manufacturer's article stops. LG treats CO as a service item.
Exact questions
Common questions
What does CO, Er CO mean on a LG refrigerator?+
Communication error: LG says the CO code indicates a communication error between the main board and the display. LG separately lists C1 as a communication error between the dispenser and the display.
Does CO affect the cooling?+
The refrigerator may keep cooling even when the display cannot communicate, but check the temperature and food. If the compressor stops, call for service.
Can a power surge cause a communication error?+
It can upset the boards, which is why one power reset is worth trying before service.
Will it clear by itself?+
Sometimes after a power reset; if not, call service.
Is it safe to keep using the refrigerator while CO shows?+
The refrigerator may keep cooling while the display has lost contact with the main board, but you cannot rely on it. Check the food temperature with a thermometer after a few hours, and if either section is warm, move perishables to a cooler and call LG service.