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Error code reference

Maytag Microwave Error Code F3

Thermistor short circuit detected after cooking.

Maytag codesMaytag microwave codes

Thermistor short circuit detected after cooking.

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What F3 means on a Maytag microwave

The F3 error code on a Maytag microwave indicates that the control board has detected a short circuit condition in the thermistor circuit after a cooking cycle has completed. The thermistor is a temperature-sensing resistor whose electrical resistance changes in a predictable way as temperature rises and falls. Under normal operating conditions, the thermistor provides the control board with continuous resistance readings that correspond to the internal cavity temperature. When the control detects a resistance value that falls below the expected minimum threshold, it interprets this as a short circuit and triggers the F3 fault.

A thermistor short circuit means the component's resistance has dropped to near zero ohms, which is outside the valid operating range. This condition is specifically flagged after cooking, meaning the fault is triggered when the control board performs a post-cycle temperature check. This timing is significant because it rules out certain transient electrical issues and points more directly to a degraded or failed thermistor, a wiring harness problem, or a damaged control board input circuit.

Common contributors to this fault include a failed thermistor that has developed an internal short, damaged wiring between the thermistor and the control board such as pinched or melted insulation causing two conductors to contact each other, or corrosion at the thermistor connector terminals. In some cases, moisture intrusion into the cavity or the component mounting area can create a conductive path that mimics a short circuit. Diagnosing the fault requires isolating the thermistor from the wiring harness and measuring its resistance directly with a multimeter to determine whether the component itself or the surrounding wiring is at fault.

Source: manufacturer service documentation.

Common causes of F3

  1. 01

    Failed thermistor

    Part replacement

    The thermistor itself has developed an internal short circuit, causing its resistance to drop to near zero. Disconnecting the thermistor and measuring its resistance with a multimeter will confirm this if the reading is close to zero ohms rather than a value appropriate for the ambient temperature.

  2. 02

    Damaged wiring harness

    Part replacement

    Wires connecting the thermistor to the control board may have pinched, melted, or frayed insulation that allows two conductors to contact each other, creating a short. Visually inspect the wiring harness for signs of heat damage, pinch points, or bare copper conductors touching adjacent wires.

  3. 03

    Corroded or contaminated connector terminals

    Wiring / connection

    Moisture or food residue can enter the thermistor connector and create a conductive bridge between terminals, producing a false short circuit reading. Inspecting the connector for discoloration, corrosion, or visible contamination can identify this issue.

  4. 04

    Moisture intrusion near the thermistor mounting point

    Wiring / connection

    Liquid that has entered the microwave cavity or the area where the thermistor is mounted can create a conductive path that the control board reads as a short. Look for water staining or residue around the thermistor and its mounting location.

  5. 05

    Faulty control board thermistor input circuit

    Part replacement

    If the thermistor and all associated wiring test within normal ranges, the fault may originate in the control board's input circuit that reads thermistor resistance. A damaged or failed control board will require replacement to resolve the F3 code.

See the test procedure for each cause

Frequently asked questions about F3

What does F3 mean on a Maytag microwave?
The F3 code on a Maytag microwave means the control board has detected a short circuit in the thermistor, which is the component that monitors internal cooking cavity temperature. The fault is triggered after a cooking cycle when the control checks the thermistor's resistance reading. This indicates the thermistor, its wiring, or the control board input circuit requires inspection and likely repair before the appliance should be used again.
Can I fix the F3 error code on my Maytag microwave myself?
A technically experienced DIYer may be able to diagnose and resolve the F3 code by testing the thermistor resistance with a multimeter and inspecting the wiring harness for damage or corrosion. Replacing a thermistor is generally straightforward if the component is accessible and a compatible replacement part is available. However, microwave repair involves capacitors that can store lethal voltage even when the unit is unplugged, so internal work should only be performed by those familiar with high-voltage appliance safety procedures.
Is it safe to use my Maytag microwave when the F3 code is showing?
Continued use of the microwave while the F3 code is active is not recommended. The thermistor is a safety-related component that helps the control board monitor temperature and prevent overheating. Operating the appliance without a functioning thermistor circuit means the microwave cannot properly detect abnormal temperature conditions during cooking.
How much does it cost to repair a Maytag microwave F3 error?
Repair costs depend on which component has failed. Thermistor replacement parts typically range from around $10 to $40, while a new control board can range from $80 to $200 or more depending on the model. If you hire a professional appliance technician, expect to add labor costs of roughly $75 to $150 on top of parts, though total costs vary by region and service provider.
Will resetting my Maytag microwave clear the F3 error code?
Unplugging the microwave for a few minutes and restoring power may temporarily clear the F3 code, but the fault will return if the underlying problem with the thermistor or its wiring has not been corrected. Because the fault is detected after cooking, it will typically reappear the next time you run a cooking cycle. A reset alone is not a repair and the root cause should be diagnosed and addressed.

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