F3H and F4E4 point to the humidity thermistor or its wiring.
Model compatibility: KitchenAid reuses codes across series and model years, so F3H / 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
Possible problem with the humidity thermistor or its wiring.
What F3H and F4E4 report
When a KitchenAid over-the-range microwave displays F3H or F4E4, the possible fault is the humidity thermistor or the wiring that connects it. The two support pages are worded identically.
What the page tells you, and what it skips
Given: the humidity thermistor or its wiring may be the problem.
Given: the first thing to try is a one-minute breaker reset.
Missing: which microwave feature relies on the humidity reading, how the unit acts with the code showing, and any inspection an owner could carry out.
The source offers only the reset and the service step.
How to run the reset
Switch the microwave’s breaker(s) off and wait one minute.
Switch them on again.
Remain close for a minute to see if F3H or F4E4 comes back.
Operate the microwave to make sure it works.
If the reset fails
The help page’s remaining path is service. Note which of the two codes you saw, although the article treats them as one fault, so either number is enough when booking. Add the model number and mention the reset you tried. Do not open the microwave to hunt for the part; that is general safety advice, not a request made by the support page.
Easily confused codes
F3H1: a separate entry that names the humidity sensor, not the thermistor.
Los Angeles owners can phone (310) 363-8964 to arrange KitchenAid microwave service. Read out the code on the display and the model number when you call.
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 KitchenAid appliance?
Book a specialist visit for a clear estimate and approval before any repair.
