Kenmore Refrigerator ER CO Error: Control Board Communication Error
The kenmore refrigerator er co error is a fault signal from the control board — this guide walks through what it means, common causes, and safe diagnostic steps. What Does Kenmore Refrigerator Error Code Er CO Mean? Er CO on a Kenmore Elite 795-series refrigerator stands for Communication Error. The refrigerator uses two separate control […]
Quick Assessment
Answer to continue safely
Is it safe to keep using?
No. A persistent Er CO means the refrigerator cannot reliably execute temperature regulation, defrost cycles, or ice maker commands. Food safety is at risk if the fault is not resolved promptly — do not leave perishables unmonitored.
Can I reset the code?
Yes. A 5-minute hard reset clears Er CO if the cause was a transient communication bus glitch. If a board or wire harness has failed, Er CO returns within minutes of the reset and the underlying hardware must be replaced.
When to stop immediately?
Stop if you notice: Er CO returns within 5 minutes of any power reset, Compartment temperatures are uncontrollable or both sections are warming simultaneously.
Symptoms You May Notice
Er CO displayed on the door panel with temperature controls unresponsive
The display board shows Er CO and may not respond to button presses for temperature adjustment, ice maker control, or other settings because the UI board has lost its communication link to the main board.
Ice maker stops producing ice and will not respond to test cycle
The ice maker receives its commands from the main power control board via the data bus — when communication fails, the ice maker halts production and cannot be started via the front panel controls.
Refrigerator may revert to default cooling mode or shut down entirely
Without communication between boards, the main power control board may default to a fixed compressor duty cycle or enter a protective shutdown, causing erratic temperature behavior in both compartments.
Compartment temperature readouts disagree with an independent thermometer
Because status data from the main board is not reaching the display, the temperatures shown on the door panel remain frozen at a past value or drift far from the actual compartment temperature measured by a separate appliance thermometer.
Possible Causes
Loose or damaged wire harness between the main and display boards
The multi-conductor harness running from the main power control board at the rear to the display board on the freezer door has a loose connector or broken wire — the most common and easiest-to-fix cause of Er CO.
DIY PossibleFailed display (UI) control board
The display board has failed internally and is no longer able to transmit or receive data on the communication bus, even though the main power control board is functioning normally.
Requires ProfessionalFailed main power control board
The main PCB's communication controller has failed, preventing it from establishing a data link with the display board — often follows a power surge or voltage spike on the supply line.
Requires ProfessionalSafe Checks You Can Do
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1
Perform a 5-minute hard reset
Unplug the Kenmore Elite refrigerator at the wall for a full 5 minutes to completely discharge all boards. Reconnect power and observe whether Er CO reappears within 10 minutes. A one-time Er CO caused by a power glitch often clears permanently with a single reset.
If Er CO returns within minutes of the reset, the fault is in the hardware — wiring or a board — and further resets will not resolve it. Proceed to harness inspection.
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2
Inspect and reseat the wire harness connectors
Pull the refrigerator away from the wall and locate the main power control board behind the lower rear panel (two screws). Inspect all wire harness connectors plugged into the board for loose fitment or visible damage. Press each connector firmly until you hear or feel it click fully seated. Also inspect the harness where it enters the hinge area — this is a flex point prone to wire fatigue.
The hinge-area harness on 795-series French Door and bottom-freezer models is a known wear point. Gently flex the harness at the hinge while monitoring whether the Er CO display clears or changes — movement-induced clearing confirms a broken wire at that point.
When to Call a Professional
Contact a qualified technician if:
- Er CO persists after hard reset and all harness connectors are confirmed seated
- Harness continuity test shows an open conductor between the main board and display board
- Er CO clears only when the hinge harness is held in a specific position — confirming a broken wire requiring harness replacement
Need Professional Help?
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