KitchenAid Over-the-Range Microwave Code F4E4: Humidity thermistor or its wiring

What F4E4 means

KitchenAid over-the-range microwave hood combinations such as the KMHC319ESS or KHMS155LSS show F4E4 when the humidity thermistor, or the wiring tied to it, may have a problem. That sensor supports automatic sensor-cook programs. A poor reading puts F4E4 on the display, and cooking that depends on it may stop or refuse to start. Sensor programs such as reheat or potato are the ones most likely to stop first.

Common causes of F4E4

Humidity thermistor sending an unusable signal
Wiring to the humidity thermistor that is loose or damaged

✓ One safe check you can try

1. Press Cancel, then open the door and let steam leave the cavity for a few minutes. 2. Wipe condensation from the interior. 3. Disconnect power for a minute, via the plug or the breaker, and restore it. 4. Start a timed cycle with a cup of water. If F4E4 returns, call for service.

! Why to stop there

The sensor sits inside the body of the unit mounted above your range.
Without a meter, a thermistor problem and a wiring problem look the same.
You get a written price first, and a 30-day workmanship warranty follows the repair.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Microwave codes

Probe or Insert ProbeKitchenAid Combination Microwave Message "Probe" or "Insert Probe": Seat the meat probe in its jack PUSH or PSHKitchenAid Built-In Microwave Message PUSH or PSH: The oven is waiting for Start Registration ErrorKitchenAid Over-the-Range Microwave Message "Registration Error": Check the home network and try again Sabbath, Sab, 5Ab, or 5A6KitchenAid Built-In Microwave Display Sabbath, Sab, 5Ab or 5A6: Sabbath Mode is on SEKitchenAid Over-the-Range Microwave Code SE: Keypad or user interface problem F6 EAKitchenAid Built-In Microwave Code F6 EA: Interface control sensed over-temperature Feature Not AvailableKitchenAid Built-In Microwave Message "Feature Not Available": Try again or disable power as the display directs F6E0KitchenAid Over-the-Range Microwave Code F6E0: Main appliance control board

F4E4F4E4 questions

Is F4E4 caused by steam from the range below?

The listed cause is the thermistor or wiring, not the range. Still, wiping the cavity dry and resetting power is a harmless first try before booking.

Can I use plain timed cooking?

Often you can, since only sensor-based programs rely on the humidity reading. If the microwave refuses everything while F4E4 shows, it needs repair. Wiping the cavity dry after steamy cooking also helps keep readings clean.

Is this the same as F4 E4 on a combination oven?

The wording is close but the units differ. On combination wall ovens it refers to the upper cavity humidity sensor and the appliance manager; here it is the thermistor circuit.