KitchenAid Combination Microwave Code F4 E4: Humidity sensor signal missing from the cavity

What F4 E4 means

With KitchenAid combination microwave-wall ovens such as the KOCE507ESS, F4 E4 means the upper cavity's humidity sensor, the microwave appliance manager, or the wiring between them may have a problem. The humidity sensor feeds sensor-cook style programs, so you may notice the code when you start one of them. The display shows F4 E4 and the microwave half halts. Expect the cycle to end almost as soon as it begins.

Common causes of F4 E4

Humidity sensor in the microwave cavity giving an unusable reading
Microwave appliance manager that does not receive the sensor signal
Wiring between sensor and manager that is loose or damaged

✓ One safe check you can try

1. Press Cancel and try a plain timed cook with a cup of water. 2. Wipe steam and splatter from the cavity and let the door stand open for ten minutes. 3. Reset power at the breaker for about a minute. 4. If F4 E4 appears again, stop using sensor programs and book a technician.

! Why to stop there

A humidity sensor is a small, sensitive part and the manager beside it is easy to confuse with it without testing.
Built-in combination units hide their wiring behind panels that hold live voltage.
We give you a written price before we replace anything, and the repair carries a 30-day workmanship warranty.

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.

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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 F4 E3KitchenAid Combination Microwave Code F4 E3: Exhaust air temperature sensor F7 E9KitchenAid Over-the-Range Microwave Code F7 E9: Is the upper vent door blocked? Flashing Time, Clock, 12:00, Power Loss or Enter TimeKitchenAid Built-In Microwave Messages Time, 12:00 and Power Loss: Set the clock after an outage

F4 E4F4 E4 questions

Does F4 E4 only appear with sensor cooking?

Often it shows when a program that relies on the humidity reading is started, but the control can also raise it on its own. Either way, the sensor circuit needs a check.

Can steam from earlier cooking cause it?

The listed causes are the sensor, the manager and the wiring. Wiping the cavity and letting it dry is still a sensible first step before you call.

Will timed cooking still work?

On some units yes, but if the display keeps the code and the microwave refuses to start, treat the microwave half as out of service until it is repaired.