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Error code reference

Kenmore Refrigerator Error Code Er FS

Abnormal Freezer Sensor

Kenmore codesKenmore refrigerator codes

Abnormal Freezer Sensor - cut or short circuit wire detected on freezer temperature sensor.

First step from the service manual

Check for a loose connection in CON6 on main PCB.

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

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What Er FS means on a Kenmore refrigerator

Er FS indicates the control board has detected a fault in the freezer temperature sensor circuit. The board continuously monitors resistance values from the freezer sensor to track compartment temperature. When it reads a resistance value consistent with a short circuit or an open circuit caused by a disconnected wire, it throws Er FS and loses the ability to accurately regulate freezer temperature. The Blue/White to Blue/White wiring pair that connects the sensor to the board is the first electrical path to inspect.

For homeowners, this means the refrigerator's brain has lost contact with the thermometer inside the freezer compartment. Without that temperature reading, the appliance cannot reliably control the cooling cycle for the freezer. You may notice the freezer running constantly, not cooling at all, or behaving erratically depending on how the control board responds to a missing sensor signal.

The root cause is almost always either a wiring problem or a failed sensor. A loose connector at the sensor or at the control board can mimic a broken sensor, so checking connections before replacing parts is essential. If connections are secure, measuring resistance across the Blue/White wires with a multimeter will tell you whether the sensor itself has failed or whether the wiring between the sensor and the board is damaged.

Source: manufacturer service documentation.

Common causes of Er FS

  1. 01

    Loose or disconnected freezer sensor connector

    Wiring / connection

    The Blue/White wire connector at the freezer sensor or at the control board can work loose over time from vibration or during previous service, breaking the circuit and triggering Er FS. Reseating the connector fully often resolves the error without any parts replacement.

  2. 02

    Failed freezer temperature sensor

    Part replacement

    The freezer sensor itself can fail internally, either shorting or opening the circuit entirely. When this happens, resistance measured across the Blue/White wires will fall outside the normal range for the compartment temperature, confirming the sensor needs to be replaced.

  3. 03

    Damaged Blue/White wiring harness

    Part replacement

    The wire run between the freezer sensor and the control board can develop a short or break due to chafing against sharp metal edges, pinching from components, or freezing and cracking in cold sections of the cabinet. A damaged harness will produce incorrect resistance readings even if the sensor itself is functional.

  4. 04

    Faulty main control board

    Part replacement

    If the sensor and all wiring check out within spec, the control board's sensor input circuit may have failed and is misreading a good signal. This is the least common cause but should be considered after the sensor and wiring have been confirmed good with a multimeter.

See the test procedure for each cause

Frequently asked questions about Er FS

What does Er FS mean on a Kenmore refrigerator?
Er FS means the control board detected a short or disconnection in the freezer temperature sensor circuit. The board can no longer get a valid temperature reading from the freezer sensor, so it throws this code to alert you to the fault. The issue is somewhere along the Blue/White to Blue/White sensor wiring or in the sensor itself.
How do I fix Er FS on a Kenmore refrigerator?
Start by unplugging the refrigerator and locating the freezer sensor connector on the Blue/White wires. Disconnect and firmly reseat it, then restore power to see if the code clears. If it returns, use a multimeter to measure resistance across the Blue/White wires at the sensor connector. A working sensor will show a resistance value consistent with the ambient freezer temperature, typically several thousand ohms near 0 degrees F. A reading of zero ohms indicates a short; an open line with no continuity indicates a broken wire or failed sensor, either of which requires part replacement.
Is it safe to keep using my Kenmore refrigerator when it shows Er FS?
Continued use carries real risk to frozen food. With the freezer sensor circuit open or shorted, the control board cannot accurately monitor freezer temperature, meaning the compressor may underrun or overrun. Food in the freezer may not stay at a safe temperature. Running the unit briefly while you source parts is generally acceptable, but monitor internal temperatures with a standalone thermometer and do not leave the unit unattended for extended periods with perishable food inside.
How much does it cost to repair Er FS on a Kenmore refrigerator?
A replacement freezer temperature sensor typically costs between $15 and $40 for parts. If you are comfortable using a multimeter and accessing the sensor location inside the freezer compartment, this is a DIY-level repair for most people. A service call from a technician will add $80 to $150 or more in labor depending on your area. Replacing the control board, if that turns out to be the cause, costs significantly more in parts, often $100 to $250, making the sensor and wiring the much more cost-effective diagnosis to rule out first.
How do I test the freezer sensor when I see Er FS?
Unplug the refrigerator, then locate the Blue/White wire connector for the freezer sensor. Disconnect it and set a multimeter to the ohms setting. Place the probes on the two sensor terminals and read the resistance. The exact expected value depends on the current temperature inside the freezer, but a functioning NTC thermistor sensor will show a measurable resistance in the thousands of ohms at freezer temperatures. A reading of zero ohms or OL (open loop) confirms a failed sensor or broken wire, and the faulty component should be replaced before running the refrigerator again.

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