Kenmore Refrigerator Er CO error code

The main control board and the display board are not communicating. Since the display board relays your temperature settings to the main board, a communication breakdown can leave the fridge running on wrong settings or cooling poorly.

Also shown as: ER CO

Last updated: September 30, 2026

Quick answer: Kenmore refrigerator error code Er CO: main board and display board can't communicate. The most common cause is loose or damaged wire harness between the boards. Try this first — power-reset the refrigerator. If that does not clear it, reseat the harness connections.

What causes the Er CO error?

  • Loose or damaged wire harness between the boards
  • Failing display control board
  • Failing main control board

How to fix Kenmore Er CO — step by step

Work through these in order, from simplest and safest first. Stop as soon as the code clears.

  1. Power-reset the refrigerator
    Unplug the fridge for five minutes to let both boards fully reset, then plug it back in and check whether the code clears.
  2. Reseat the harness connections
    Unplug the fridge and check the wire harness connections on both the display board and the main control board. Reseat anything loose and look for pinched or chewed wires.
    Safety warning: Unplug the fridge before opening any control compartments.

When to call a technician

Stop and call a qualified technician if any of these apply:
  • Wiring is sound but the code persists
  • The display is blank, frozen, or shows garbage
  • Cooling is affected

Frequently asked questions

Can a power surge cause Er CO?

Yes — surges can scramble board-to-board communication or damage a board. A surge protector on the fridge outlet is cheap insurance.

Sources

Every meaning and fix above was checked against official manufacturer documentation:

FixCode provides general troubleshooting information only — not professional repair advice. If you are unsure about any step, stop and call a qualified technician. Repairs done incorrectly can be dangerous and may void your warranty.

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