KitchenAid Combination Microwave Code F4 E2: Upper cavity thermistor circuit not reading

What F4 E2 means

A KitchenAid combination microwave-wall oven, for example the KOCE900HSS, shows F4 E2 when the upper cavity reports a problem with its sensor or thermistor, with the microwave appliance manager, or with their wiring. The code sits next to F4 E1 in the same family. Owners typically see it flash on the display, and the microwave side declines to start a cycle.

Common causes of F4 E2

Cavity thermistor or sensor sending an unreadable signal
Appliance manager for the microwave half that cannot interpret the reading
Wiring or connector between the sensor and the manager that has worked loose

✓ One safe check you can try

1. Press Cancel and look at the display again. 2. Turn the oven's breaker off, wait about a minute, and switch it back on. 3. Check that the door closes squarely and the cavity has no spills near the walls. 4. If F4 E2 appears again when you try a short cycle, leave the microwave side off and call us.

! Why to stop there

Telling a failing sensor from a weak manager needs test equipment and a known-good reference.
The microwave circuit stores dangerous voltage even when the oven is idle, so panels stay closed.
Guessing at parts is how a simple repair turns into two visits; we diagnose first and quote before working.

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 F4E1KitchenAid Over-the-Range Microwave Code F4E1: Cavity thermistor circuit F9QKitchenAid Over-the-Range Microwave Code F9Q: Reset power and watch for a minute F4E4KitchenAid Over-the-Range Microwave Code F4E4: Humidity thermistor or its wiring

F4 E2F4 E2 questions

What does the E2 in F4 E2 add?

The second part separates it from E1 in the same F4 group. Both point at the microwave cavity sensor circuit, so a technician reads the one on your display and tests the matching path.

Can I still bake in the lower oven?

Often yes, because the code names the upper microwave cavity. Keep an eye on the display, and if other messages join it, stop and call us instead of running both.

Does the repair carry a warranty?

Yes. Our work comes with a 30-day workmanship warranty, and you get the written price before we begin any repair on your combination oven. It also protects you from surprises on the invoice.