Written by
Maren Coleman Appliance Care EditorPublished October 29, 2026
VERIFIED
Error codeF4E4
ApplianceMicrowave
The humidity thermistor message
On over-the-range Whirlpool microwaves, F4E4 refers to the Humidity Thermistor. The manual says the thermistor, or the wiring running to it, may have a fault.
Steps in order
Shut off power at the breaker and wait a full minute (unplugging works too).
Switch power back on.
Let the microwave stay on for one more minute and check whether F4E4 appears again.
Run the microwave to confirm normal operation.
Close relatives
Thermistor codes sit close together in the list. F4E1 belongs to the Cavity Temperature Thermistor, while F3T1 belongs to the User Interface Thermistor.
Microwave service in the San Francisco Bay Area
For Whirlpool microwave service in San Francisco, see Whirlpool microwave repair or phone (415) 687-4102. Bring up F4E4, the model number and what you already did with the breaker.
Model compatibility: Whirlpool reuses codes across series and model years, so F4E4 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
F4E4 means the Humidity Thermistor or its wiring may be at fault.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your Whirlpool appliance?
Book a specialist visit for a clear estimate and approval before any repair.
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