KitchenAid Over-the-Range Microwave Code F3C: cavity temperature thermistor

What F3C means

KitchenAid over-the-range microwave hood combinations such as the KMHS120ESS and KMLS311HSS show F3C when there may be a problem with the cavity temperature thermistor, or the wiring to it. The thermistor measures how hot the cooking cavity gets. If its reading is unusable, the microwave may stop heating or refuse to start, and the display shows F3C.

Common causes of F3C

Cavity thermistor failed or out of range
Thermistor wiring loose
Control not reading the thermistor

✓ One safe check you can try

1. Cancel and let the cavity cool with the door open. 2. Wipe away any moisture and food residue. 3. Pull the plug for sixty seconds. 4. Reconnect and run a short test with a cup of water. 5. If F3C returns, call us.

! Why to stop there

Thermistors are small parts inside the cabinet that need testing in place
Guessing between thermistor and board adds expense
We give the price in writing and 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 E8KitchenAid Combination Microwave Code F4 E8: Inverter or its wiring flagged F9KitchenAid Over-the-Range Microwave Code F9: Two boards and their wiring are suspect ":" or "." in displayKitchenAid Built-In Microwave Display ":" or ".": The clock needs setting

F3CF3C questions

What is a thermistor?

A temperature-sensitive resistor. Its resistance changes with heat, and the control uses that to know the cavity temperature.

Why does F3C appear after a long cook?

Heat can expose a weak thermistor or connection. If it appears only after long use, tell us.

Is it safe to keep using the oven?

We would wait. Without the cavity reading, the control cannot protect against overheating.