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Error code reference

Kenmore Refrigerator Error Code CO

Communication error between Main PCB and Display PCB

Kenmore codesKenmore refrigerator codes

Communication error between Main PCB and Display PCB - short or open lead wire connecting between Main PCB and Display PCB. All systems normal operation.

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What CO means on a Kenmore refrigerator

The CO error code on a Kenmore refrigerator indicates a communication failure between the Main PCB (printed circuit board) and the Display PCB. These two boards exchange data continuously to coordinate control signals and display readings. When the connection between them is interrupted or degraded, the control system detects the loss of expected communication signals and triggers the CO code to alert the user or technician.

The most common physical causes are a short circuit or an open circuit in the lead wire harness that connects the two boards. A short occurs when two conductors in the harness make unintended contact, creating an abnormal current path. An open circuit occurs when the wire is broken, a connector pin has backed out, or corrosion has interrupted continuity. Either condition prevents the reliable data transfer the boards require to function together.

Despite the alert, the CO code description notes that all systems continue normal operation. This means the refrigerator is likely still cooling and running its standard functions, but the communication fault should be diagnosed and resolved to ensure proper long-term control and monitoring. Inspection should focus on the wiring harness routing between both boards, checking connectors for secure seating, and testing wire continuity with a multimeter to confirm whether a short or open is present.

Source: manufacturer service documentation.

Common causes of CO

  1. 01

    Loose or disconnected wire harness connector

    Wiring / connection

    The connector plugging the lead wire into the Main PCB or Display PCB may have worked loose over time due to vibration. Inspect both ends of the harness and reseat any connectors that are not fully clicked into place.

  2. 02

    Damaged or pinched lead wire

    Part replacement

    The wire harness between the two boards can become pinched, kinked, or abraded if it runs near a sharp edge or moving component. Visually trace the full length of the harness and look for visible damage or wear points.

  3. 03

    Open circuit in lead wire

    Part replacement

    A broken conductor inside the harness insulation may not be visible externally. Use a multimeter set to continuity mode to test each wire in the harness individually between the two board connectors.

  4. 04

    Short circuit in lead wire

    Part replacement

    Two or more conductors in the harness may be making unintended contact due to chafed insulation. A multimeter resistance test between adjacent wire pins can help identify a short if readings show near-zero ohms between conductors that should be isolated.

  5. 05

    Faulty Main PCB or Display PCB

    Part replacement

    If the lead wire and all connectors test good, one of the boards themselves may have a failed communication circuit. Board replacement is typically considered after wiring has been ruled out as the cause.

See the test procedure for each cause

Frequently asked questions about CO

What does CO mean on a Kenmore refrigerator?
The CO code indicates a communication error between the Main PCB and the Display PCB. It is triggered when the lead wire connecting these two boards develops a short circuit or an open circuit. The good news is that all normal refrigerator functions are reported to continue operating despite this fault.
Will resetting my Kenmore refrigerator clear the CO error code?
A power reset may temporarily clear the CO code, but if the underlying wiring fault remains, the code will return. A lasting fix requires diagnosing and repairing the lead wire or connector between the Main PCB and Display PCB rather than relying on a reset alone.
Is my food safe when a Kenmore refrigerator shows the CO error?
According to the error code data, all systems continue normal operation when the CO code appears, meaning the refrigerator should still be cooling. Monitor your temperatures with a thermometer to confirm, and address the fault promptly to avoid any future control issues.
Can I fix the CO error on my Kenmore refrigerator myself?
A knowledgeable DIYer can start by inspecting the wire harness between the two boards for loose connectors, visible damage, or pinched sections. Testing for continuity and shorts with a multimeter is also within reach for someone comfortable with basic electrical diagnostics. If the harness tests good and the fault persists, board replacement is best left to a qualified technician.
How much does it cost to repair the CO error on a Kenmore refrigerator?
Repair costs vary depending on the cause. If only the lead wire harness needs replacement, parts and labor typically range from around $75 to $200. If a Main PCB or Display PCB replacement is required, costs can range from $150 to $400 or more depending on part availability and local labor rates.

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