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Error code reference

Whirlpool Freezer Error Code 01

RC Thermistor diagnostic step

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RC Thermistor diagnostic step - displays temperature in °F/°C; shows 'OP' for open circuit or 'SH' for short circuit.

First step from the service manual

Check wires and connectors. Disconnect power or unplug product. Check resistance given in the diagram on page 1.

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

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What 01 means on a Whirlpool freezer

Error code 01 on a Whirlpool freezer is a diagnostic display for the RC (refrigerant circuit) thermistor. When this code is active, the control board reads and displays the current temperature sensed by the thermistor in either Fahrenheit or Celsius. If the thermistor circuit has failed, the display will show 'OP' to indicate an open circuit condition or 'SH' to indicate a short circuit condition. This is a diagnostic mode rather than a fault lockout, meaning the freezer may still attempt to operate while this code is present.

The RC thermistor is a negative temperature coefficient (NTC) sensor, meaning its electrical resistance decreases as temperature rises. The control board uses this resistance value to determine the refrigerant or compartment temperature and make defrost and compressor cycling decisions. An open circuit typically results from a broken wire, corroded connector, or a failed thermistor with resistance reading above the expected range. A short circuit occurs when the resistance drops far below the expected range, often due to a damaged sensor or wiring insulation failure.

The first diagnostic step involves a visual inspection of all wiring harnesses and connector terminals associated with the thermistor, followed by disconnecting power to the unit before performing any resistance testing. The correct resistance value for a healthy thermistor at a given temperature is specified in the wiring diagram included with the product documentation. Comparing the measured resistance to the specified value at the current ambient temperature will confirm whether the thermistor itself has failed or whether a wiring fault is responsible.

Source: manufacturer service documentation.

Common causes of 01

  1. 01

    Faulty RC thermistor

    Part replacement

    The thermistor itself has failed, causing resistance to fall outside the expected range and triggering an 'OP' or 'SH' reading. Resistance testing at the sensor terminals will confirm this if the values do not match the temperature-resistance chart in the wiring diagram.

  2. 02

    Loose or corroded connector

    Wiring / connection

    Connectors in the thermistor wiring harness can loosen or corrode over time, creating an intermittent or complete open circuit. Inspect all connector terminals for oxidation, bent pins, or poor seating.

  3. 03

    Damaged wiring harness

    Part replacement

    Wires leading to the thermistor can be pinched, cut, or have degraded insulation, causing either an open or short circuit condition. A visual inspection along the full length of the harness will often reveal the damage.

  4. 04

    Moisture or ice intrusion at the sensor

    Wiring / connection

    Ice buildup around the thermistor or moisture entering a connector can alter resistance readings or cause a short circuit. Check the sensor mounting location for excessive frost or water accumulation.

  5. 05

    Control board communication fault

    Part replacement

    In rare cases, the control board itself may misread a healthy thermistor signal due to an internal fault on the sensor input circuit. This should only be considered after confirming the thermistor and wiring test within spec.

See the test procedure for each cause

Frequently asked questions about 01

What does 01 mean on a Whirlpool freezer?
Error code 01 on a Whirlpool freezer activates the RC thermistor diagnostic display, showing the current temperature reading from that sensor in Fahrenheit or Celsius. If the sensor circuit has an open circuit, the display will show 'OP', and if there is a short circuit, it will show 'SH'. This code points to a problem with the temperature sensor or its associated wiring. Diagnosing it requires checking connectors and testing thermistor resistance with power disconnected.
Can I fix error code 01 on my Whirlpool freezer myself?
A knowledgeable DIYer can perform the initial diagnostic steps, including inspecting the wiring harness and connectors for visible damage or corrosion. If resistance testing with a multimeter confirms the thermistor is out of spec, replacing the sensor is a straightforward repair on most models. However, if the wiring or control board is involved, professional service is recommended to avoid further damage.
Is it safe to keep using my Whirlpool freezer when error code 01 is displayed?
If the display shows an 'OP' or 'SH' condition, the control board is not receiving accurate temperature data, which means the freezer may not maintain safe storage temperatures. It is best to address the fault promptly and check that food is being stored at the correct temperature using an independent thermometer in the meantime. Continued use with a faulty thermistor risks food spoilage.
Will resetting my Whirlpool freezer clear the 01 error code?
Unplugging the freezer and restoring power may temporarily clear the display, but if the underlying wiring fault or thermistor failure is still present, the code or abnormal reading will return. A reset does not repair a failed sensor or damaged connector. The root cause must be diagnosed and corrected for the code to clear permanently.
How much does it cost to repair error code 01 on a Whirlpool freezer?
If only a thermistor replacement is needed, parts typically range from around $15 to $60 depending on the specific model, with labor costs adding $75 to $150 or more if a technician performs the repair. If the issue is a wiring harness or control board, costs can be higher, potentially ranging from $150 to $400 or more for parts and labor combined. Getting a diagnostic service call will help confirm exactly which component needs to be replaced before committing to a repair.

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