Kenmore Refrigerator Error Code Er CO — Communication Error Between Boards
What this means
The Er CO error code on Kenmore refrigerators indicates a communication failure between the main control board (typically at the rear bottom of the unit) and the display/user interface board (on the door or top front panel). This prevents you from adjusting temperature settings or using dispenser functions. Causes include a loose wire harness, damaged wiring through the door hinge, or a failed board.
Step-by-step fix
4 stepsReset the refrigerator
Unplug the refrigerator for 5 minutes and plug it back in. This resets both boards and can clear a communication glitch caused by a power surge or electrical noise.
After plugging back in, wait 2–3 minutes for the display to fully initialize before checking if the error returns.
Inspect the door hinge wiring
On models with the display on the door, the communication wiring passes through or alongside the door hinge. Open and close the door while observing the wires near the hinge. Look for pinched, frayed, or broken wires in the wire harness.
The top hinge area is the most common failure point — years of opening and closing the door can fatigue and break wires at the bend.
Check board connections
Unplug the refrigerator. Access the main control board by removing the rear lower panel. Check that all wire harness connectors are firmly seated. Then access the display board (remove the screws behind the display panel) and check those connections too.
Wiggle each connector gently while checking for any intermittent connection — a connector that seems seated may have corroded pins.
Test the wiring harness
Using a multimeter, test continuity through each wire in the communication harness between the main board and the display board. A broken wire will show an open circuit. If a wire is broken, it can be spliced and soldered.
Label each wire as you test it so you don't lose track in a multi-wire harness.
When to call a professional
If all wiring tests good, one of the two boards has likely failed. Determining which board is faulty and replacing it requires specialized diagnostic tools and should be done by a qualified refrigerator technician.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Main Control Board
Part #WPW10312695 · $100–$200
Only if confirmed faulty after wiring checks
Display Board / User Interface
Part #WPW10346771 · $80–$150
Only if confirmed faulty after wiring checks
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