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Error code reference

KitchenAid Microwave Error Code F3T

Temperature sensor failure (oven temperature out of expected range).

KitchenAid codesKitchenAid microwave codes

Temperature sensor failure (oven temperature out of expected range).

First step from the service manual

Check that the oven temperature is not below 41°F (5°C) or above 140°F (60°C).

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What F3T means on a KitchenAid microwave

The F3T error code on a KitchenAid microwave indicates a temperature sensor failure, specifically that the oven cavity temperature has been detected outside the expected operating range. The sensor involved is a thermistor or thermocouple responsible for monitoring internal cavity temperature and reporting it to the control board. When the sensed temperature falls below 41°F (5°C) or rises above 140°F (60°C) during normal operation, the control board interprets this as an out-of-range condition and triggers the F3T fault to prevent unsafe or inaccurate cooking cycles.

The temperature sensor circuit feeds resistance or voltage data to the main control board continuously during operation. A failed or degraded sensor can report values that fall outside the board's accepted parameters even when the actual cavity temperature is normal. This can result from a broken sensor element, a wiring harness fault such as a loose connector or damaged wire, or a control board input circuit that is no longer reading the sensor correctly. Environmental conditions, such as operating the microwave in an extremely cold garage or a very hot ambient environment, can also push actual temperatures outside the acceptable window.

Before assuming a faulty sensor, the first diagnostic step is to verify that the ambient and cavity temperatures are within the acceptable range of 41°F to 140°F (5°C to 60°C). If the unit has been stored or operated in an extreme environment, allowing it to return to a normal temperature may clear the fault. If the error persists under normal conditions, further electrical diagnosis of the sensor, its wiring, and the control board is required.

Source: manufacturer service documentation.

Common causes of F3T

  1. 01

    Extreme ambient or cavity temperature

    Wiring / connection

    If the microwave has been stored or is operating in a space where temperatures are below 41°F (5°C) or above 140°F (60°C), the control board will trigger F3T as a valid out-of-range reading. Allow the unit to reach a normal room temperature and retry before performing further diagnosis.

  2. 02

    Faulty temperature sensor (thermistor)

    Part replacement

    A degraded or failed thermistor can report resistance values that correspond to temperatures outside the accepted range even when the cavity is at a normal temperature. The sensor should be tested for proper resistance values at a known ambient temperature.

  3. 03

    Loose or damaged sensor wiring connector

    Wiring / connection

    A disconnected, corroded, or pinched wire in the sensor harness can cause an open or short circuit that the control board reads as an out-of-range temperature signal. Inspect all connectors between the sensor and the control board for damage or poor seating.

  4. 04

    Broken sensor wire

    Part replacement

    Physical damage to the sensor wire, often caused by heat exposure or sharp cabinet edges, can interrupt the signal entirely and cause the control board to register an implausible temperature reading. A continuity test along the full length of the wire will identify this fault.

  5. 05

    Faulty main control board

    Part replacement

    If the sensor and all associated wiring test correctly, the input circuit on the main control board may have failed and is misreading the sensor signal. This is the least common cause and should only be considered after the sensor and wiring have been ruled out.

See the test procedure for each cause

Frequently asked questions about F3T

What does F3T mean on a KitchenAid microwave?
F3T indicates a temperature sensor failure, meaning the microwave's control board has detected an oven cavity temperature outside the accepted range of 41°F (5°C) to 140°F (60°C). This can be caused by a genuinely extreme ambient temperature, a failed thermistor, damaged wiring, or in rare cases a faulty control board. The unit will not operate normally until the fault is resolved.
Can I fix the F3T error myself?
Some causes of F3T are DIY-accessible. If the microwave was in a cold or hot environment, simply moving it to a room-temperature location and waiting may clear the code. Checking and reseating wiring connectors is also manageable for experienced DIYers. However, testing and replacing the thermistor or control board involves working near high-voltage components and is best handled by a qualified technician.
Is it safe to use my KitchenAid microwave while the F3T code is showing?
No, you should not continue using the microwave while F3T is active. The error indicates the temperature monitoring system is not functioning correctly, which means the unit cannot accurately regulate or safely monitor cooking conditions. Continued use without a functional temperature sensor could result in overheating or inaccurate cooking results.
Will resetting my KitchenAid microwave clear the F3T error?
A power reset, performed by unplugging the unit for one to two minutes and restoring power, may temporarily clear the code if the fault was caused by a transient condition such as a brief temperature extreme or a loose connection. However, if the underlying cause is a failed sensor or damaged wiring, the F3T code will return. A reset alone is not a repair.
How much does it cost to repair an F3T error on a KitchenAid microwave?
Repair costs vary depending on what component has failed. A replacement thermistor is generally an inexpensive part, with the total repair cost including labor typically ranging from $75 to $175. If the main control board is at fault, parts and labor costs can range from $150 to $350 or more. Getting a diagnostic estimate before authorizing repairs is advisable, particularly on older units.

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