Whirlpool Microwave F3T4 — What It Means & How to Fix It
F3T4 points to the magnetron temperature thermistor or its wiring; reset power for a minute, and leave any repair strictly to a technician.
What this code means
Whirlpool says F3T4 may mean a problem with the magnetron temperature thermistor or the associated wiring. The magnetron generates the microwaves and sits in the high-voltage section.
Whirlpool over-the-range microwaves.
Most likely causes
| Cause | How likely | DIY-fixable? |
|---|---|---|
| Magnetron thermistor fault | Common | No — technician job |
| Magnetron overheating from blocked airflow | Occasional | Partly — clear vents |
| Wiring fault | Occasional | No — technician job |
What you can try yourself
- Stop cooking and let the unit cool.
- Check vents and grease filters are not blocked.
- Reset power for one minute.
- Schedule service if it returns; never remove the cabinet.
When to call a technician
- Repeat code.
- No heating.
- Loud hum or burning smell.
Typical professional repair cost: About $150–$350.
Frequently asked questions
What does F3T4 mean?
A possible problem with the magnetron temperature thermistor or its wiring.
Can I check the magnetron?
No. The high-voltage section can hold a lethal charge even unplugged.
Could blocked filters cause it?
Whirlpool does not say; keeping airflow clear is good practice.
Sources checked
Error meanings can vary by model. This guide was checked against the documentation above; use the manual for the model number on your own appliance when it differs.
Related Whirlpool codes
- Whirlpool Microwave E03 E03 — or a plain F2 — means the keypad reported a problem to the control board; reset power for one minute and call for service if it comes back.
- Whirlpool Microwave SE SE means there is a problem with the keypad (user interface) or its wiring — clean and dry the panel, reset power for a minute, and call service if SE remains.
- Whirlpool Microwave E11 E11 and E12 point to the microwave's gas sensor — the sensor used for automatic cooking — or its wiring; reset power for a minute, and expect to need a technician if it returns.
- Whirlpool Microwave E13 E13 means the oven did not pre-heat correctly, with a possible problem in the appliance control board or its wiring; reset power for a minute and call service if it repeats.
More: all Whirlpool microwave codes · all Whirlpool codes · search by symptom