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Error code reference

GE Refrigerator Error Code Er CO

Communication error between MICOM of Main PCB and Display MICOM, caused by poor communication connection or…

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Communication error between MICOM of Main PCB and Display MICOM, caused by poor communication connection or poor TR of transmitter/receiver Tx/Rx.

First step from the service manual

Check for loose connection, then check Red to White/Red at CON101 on the Display PCB for 12V.

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

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What Er CO means on a GE refrigerator

The Er CO error code on a GE refrigerator indicates a communication failure between the main PCB's MICOM (microcomputer controller) and the display MICOM. These two controllers must continuously exchange data signals to coordinate refrigerator functions and display accurate status information. When this communication link breaks down, the main board can no longer confirm that the display module is receiving or transmitting correctly, and the Er CO fault is triggered.

The error can originate from two primary sources: a physical wiring issue or a failure in the transmitter/receiver (Tx/Rx) circuitry, sometimes referred to as the TR. The communication line runs between the main PCB and the display PCB, and any loose, corroded, or damaged connector along that path can interrupt the signal. The specific connection point to inspect is CON101 on the display PCB, where the Red wire to the White/Red wire junction should carry 12V when properly powered.

Diagnosing this fault begins with a visual and physical inspection of all connectors between the main board and display board. If the connectors are secure and the 12V supply at CON101 is confirmed, the fault likely points to a failed display PCB or main PCB where the MICOM's communication circuitry has degraded. Both boards are involved in maintaining this signal, so systematic testing is necessary to isolate which component is responsible before replacing parts.

Source: manufacturer service documentation.

Common causes of Er CO

  1. 01

    Loose or disconnected wiring connector

    Wiring / connection

    A loose connector between the main PCB and the display PCB is the most frequent cause of Er CO. Inspect CON101 on the display PCB and all intermediate connectors for secure seating and signs of corrosion or damage.

  2. 02

    No 12V supply at CON101 on display PCB

    Wiring / connection

    If the Red to White/Red wire connection at CON101 is not delivering 12V, the display MICOM cannot operate properly and communication will fail. This may point to a wiring fault or a problem with the main PCB's power output.

  3. 03

    Failed transmitter/receiver (Tx/Rx) circuitry

    Part replacement

    The Tx/Rx components on either the main PCB or the display PCB can degrade or fail, breaking the communication signal even when wiring and voltage are intact. This typically requires replacing the affected board.

  4. 04

    Faulty display PCB

    Part replacement

    If connectors and voltage check out correctly, the display PCB's MICOM may have failed internally, preventing it from sending or receiving communication signals from the main board.

  5. 05

    Faulty main PCB

    Part replacement

    If the display board tests as functional and wiring is confirmed good, the main PCB may be the source of the communication failure, with its MICOM unable to properly drive the communication line.

See the test procedure for each cause

Frequently asked questions about Er CO

What does Er CO mean on a GE refrigerator?
Er CO on a GE refrigerator indicates a communication error between the main PCB's MICOM and the display MICOM. The two control modules have lost their data connection, which is needed for the refrigerator to operate and display information correctly. The fault is caused by either a loose or faulty wiring connection or a failure in the transmitter/receiver circuitry on one of the boards.
Can I fix Er CO on my GE refrigerator myself?
A homeowner comfortable with basic appliance repair can start by checking for loose wire connectors between the display panel and the main control board, particularly at CON101 on the display PCB. If reconnecting the wiring does not resolve the issue, testing voltage at that connector and replacing a control board are tasks better suited to a technician with electrical diagnostic experience.
Will resetting my GE refrigerator clear the Er CO error?
A power reset, such as unplugging the refrigerator for a few minutes, may temporarily clear Er CO if the fault was caused by a momentary signal disruption. However, if the underlying cause is a loose connector or a failing PCB component, the error will return. A proper repair requires identifying and fixing the root cause of the communication failure.
Is it safe to keep using my GE refrigerator when Er CO is displayed?
An Er CO error means the main control board and display are not communicating properly, which can affect the refrigerator's ability to regulate temperature correctly. It is advisable to check food temperatures and address the error promptly rather than relying on the unit to maintain safe storage conditions while the fault is active.
How much does it cost to repair an Er CO error on a GE refrigerator?
If the fix is simply reseating a loose connector, there may be little to no parts cost, though a service call fee typically ranges from $75 to $150. If a display PCB or main PCB replacement is needed, parts alone can range from $100 to $350 or more depending on the model, with total repair costs including labor often falling between $200 and $500.

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