F3H and F4E4: KitchenAid flags the humidity thermistor and 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.
What this code means
Possible problem with the humidity thermistor or its wiring.
A F3H or F4E4 message on a KitchenAid over-the-range microwave reports a possible problem with the humidity thermistor or its wiring. KitchenAid wrote the two help entries with the same text.
At a glance
| Code | F3H / F4E4 |
|---|---|
| What it means | Possible problem with the humidity thermistor or its wiring. |
| What you can check | Turn the microwave breaker off and count to sixty, switch it on, and watch for a minute. Run the microwave briefly to verify operation. |
| When to call a technician | If the code is still on screen after the reset, book a service visit. Leave the cover on, and mention which code showed. |
Limits of the source
The articles state the suspect part and the one-minute breaker reset. They do not state what the microwave uses the humidity reading for, how it behaves with the code, or what an owner might inspect. That leaves only the reset and service.
Reset sequence
- Turn the circuit breaker(s) for the microwave off and count to sixty.
- Turn the breaker(s) on.
- Spend a minute with the microwave watching for F3H or F4E4.
- Run it briefly to verify operation.
Do not mix up these entries
The humidity sensor has its own code, F3H1. The thermistor for the cooking cavity is covered under F3C and F4E1.
Code still on screen
A failed reset leaves service as the help page’s last option. Since the support article treats F3H and F4E4 as the same fault, whichever one you saw will do for a booking. Mention the model number and the reset. Leave the cover on the microwave; this is general safety, not something KitchenAid asks.
Humidity thermistor service in KitchenAid metro areas
Customers in the Miami, New York, Houston, Los Angeles and San Diego metro areas can call (844) 919-2035 about a KitchenAid microwave showing this code. Have the displayed code and your model number at hand.
Source: KitchenAid Product Help, Over-the-Range Microwave Error Code
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.
Sources & references
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