Kenmore Microwave Error F3

⚡ Quick Answer: The Kenmore microwave F3 error indicates a malfunctioning temperature sensor, often leading to erratic display behavior or failure to heat. This issue... ⚠️ Difficulty Varies

What Does Error F3 Mean?

The Kenmore microwave F3 error indicates a malfunctioning temperature sensor, often leading to erratic display behavior or failure to heat. This issue typically arises from a short or abnormal reading in the thermistor, where the sensor fails to detect temperature changes as expected during cooking. Common causes include a faulty temperature sensor or loose wiring connections, which can affect the microwave's performance. Regular maintenance and troubleshooting can help identify the issue before seeking professional repair.

Common Symptoms:

  • Error F3 appears on display when cooking or shortly after starting
  • Microwave may stop heating correctly when the error appears

Possible Causes

  • Thermistor/Temperature Sensor Short or Faulty (medium)
  • Loose or Damaged Sensor Wiring or Connector (medium)

How to Fix Error F3

DIY Fix Basic Troubleshooting Before Service

  1. Unplug the microwave from power and wait 5–10 minutes, then plug back in to reset the control
  2. Ensure the inside of the microwave is dry and clean (no moisture on sensor or wiring)
  3. Observe whether the error returns under same conditions

Technician Only Inspect and Replace Temperature Sensor and Wiring

  1. Disconnect power and access the internal components per model service manual
  2. Locate the temperature sensor/thermistor and inspect its wiring harness and connectors for damage or shorts
  3. Measure the sensor resistance with a multimeter to confirm if it is outside specification
  4. Replace the temperature sensor and any damaged wiring, then retest operation

Parts needed: Temperature sensor/thermistor, Wiring harness and connectors

🛑 When to Call a Pro:
  • If error F3 persists after basic reset and visual inspection
  • If you are not comfortable opening the microwave due to high-voltage risks

Next step

Choose the next step for F3

Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.

Based on diagnostic data

Most relevant component to inspect

Temperature Sensor

Monitors the internal temperature to ensure correct operation and prevent overheating.

Typical part-only price
$15 - $35
DIY difficulty
Easy
Estimated time
15-30 mins
Where can I find the model number?

Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.

Find a part that fits my model

Verify the complete model and part number on the retailer's compatibility page before ordering.

Other parts options

Check related components first; use model search as a fallback.

Possible related component

Thermistor

Measures precise temperature changes and sends resistance feedback to the control board.

$15 - $35 · Easy · 15-30 mins

Check fit & price
Possible related component

Wiring Harness

Connects controls, sensors, motors, and other electrical components inside the appliance.

$20 - $120 · Medium · 30-90 mins

Check fit & price
Model number required

Model-compatible Microwave parts

Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.

Find a part that fits my model

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Technical Specifications

wattage 1000W
component Temperature Sensor
resistance 1-5 ohms
part_number WB21X10120
voltage_rating 120V AC

Common Questions

What does F3 error mean on kenmore microwave?

F3 error indicates a malfunctioning temperature sensor, often causing heating issues.

Can I fix kenmore microwave F3 error myself?

Yes, you can try resetting the microwave and checking for loose connections.

How much does it cost to fix F3 error?

Repair costs are medium, covering parts and labor for the temperature sensor.

When should I call a technician for F3?

Call a technician if the error persists after a reset or if you are uncomfortable with repairs.

Data last verified: 2026-07-25

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