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Error code reference

Kenmore Refrigerator Error Code E CO

Communication error

Kenmore codesKenmore refrigerator codes

Communication error — communication failure between Main PCB and Display PCB.

First step from the service manual

Check for loose connections; check hinge connection; measure voltage at CON101 pins 1 & 2 for 12V.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E CO means on a Kenmore refrigerator

The E CO error code on a Kenmore refrigerator indicates a communication failure between the Main PCB (the primary control board) and the Display PCB (the user interface board). These two boards continuously exchange data signals to coordinate temperature settings, compressor operation, fan speeds, and user inputs. When that communication link breaks down or becomes unstable, the control system flags E CO to alert that the refrigerator cannot reliably coordinate between its two primary control points.

The communication link between these boards typically runs through a wiring harness that passes through or near the door hinge area. This routing makes the hinge connection a particularly common failure point, since repeated door opening and closing cycles can stress, fray, or loosen the wiring over time. The first diagnostic step is to check all connectors in this harness for looseness or corrosion, and specifically to measure the voltage at CON101 pins 1 and 2. A healthy system should read 12V DC at those pins. A reading significantly below 12V, or no voltage at all, points to either a power supply issue on the Main PCB or a break in the wiring.

If the wiring and connectors check out and 12V is confirmed at CON101, the fault likely lies within one of the two boards themselves. Either the Main PCB is failing to transmit the signal correctly, or the Display PCB is failing to receive and respond to it. In some cases, a firmware or logic fault on one board can mimic a wiring failure, so a power reset is a reasonable early step before condemning components.

Source: manufacturer service documentation.

Common causes of E CO

  1. 01

    Loose or disconnected wiring harness connector

    Wiring / connection

    The most frequent cause is a connector in the harness between the Main PCB and Display PCB that has worked loose over time. Inspect all connectors along the communication path and reseat any that feel loose or show signs of corrosion.

  2. 02

    Damaged hinge connection wiring

    Part replacement

    The communication wiring passes through the door hinge area and can become pinched, frayed, or broken from repeated door use. Carefully inspect the wire routing at the hinge for visible damage, kinking, or broken insulation.

  3. 03

    Missing or low 12V supply at CON101

    Part replacement

    If voltage measured at CON101 pins 1 and 2 is absent or well below 12V DC, the Main PCB may not be providing adequate power to sustain communication. This can indicate a failing Main PCB or a fault in the power supply circuit feeding it.

  4. 04

    Failed Display PCB

    Part replacement

    If wiring and voltage check out correctly, the Display PCB itself may have failed and is no longer able to receive or respond to signals from the Main PCB. Substituting a known-good Display PCB is the most reliable way to confirm this.

  5. 05

    Failed Main PCB

    Part replacement

    If the Display PCB tests good and wiring is intact, the Main PCB may be the source of the communication fault, either failing to transmit signals or producing incorrect output. Replacement of the Main PCB would be required to resolve this.

See the test procedure for each cause

Frequently asked questions about E CO

What does E CO mean on a Kenmore refrigerator?
E CO indicates a communication error between the Main PCB and the Display PCB. These two control boards exchange data constantly to run the refrigerator, and when that link fails, the unit displays E CO to signal the breakdown. The most common causes are loose wiring connectors or damaged wiring near the door hinge.
Can I fix the E CO error myself?
A homeowner comfortable with basic appliance inspection can start by checking that all visible wiring connectors are firmly seated, particularly near the door hinge area where wiring is prone to wear. However, measuring voltage at CON101 and diagnosing board-level faults requires a multimeter and some technical experience. If the wiring looks intact and the error persists, a qualified technician should evaluate the control boards.
Is it safe to use my Kenmore refrigerator while E CO is displayed?
An E CO error means the control boards are not communicating properly, so temperature control and other functions may not operate reliably. It is generally not advisable to trust the refrigerator to maintain safe food temperatures while this code is active. The issue should be diagnosed and resolved before storing perishable food.
Will resetting the refrigerator clear the E CO code?
A power reset, done by unplugging the refrigerator for several minutes and then plugging it back in, can sometimes clear a temporary communication glitch. If the error returns after the reset, the underlying cause, such as a loose connector, damaged wire, or faulty board, has not been resolved and needs further diagnosis.
How much does it cost to repair a Kenmore refrigerator E CO error?
Repair costs vary widely depending on the root cause. If the fix is simply reseating a loose connector, you may only pay for a service call, typically in the range of $75 to $150. Replacing a Display PCB or Main PCB generally adds parts costs on top of labor, with total repair bills often falling somewhere between $150 and $400 or more depending on parts pricing and local labor rates.

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