KitchenAid Combination Oven Code F4 E0: microwave inverter or its wiring

What F4 E0 means

On KitchenAid combination microwave and wall ovens such as the KOCE500ESS or KOCE900HSS, F4 E0 concerns the upper microwave cavity. The microwave inverter, or the wiring connected to it, may have a problem. The code appears on the display, and the microwave side may not heat food. The lower oven is a separate cooking space, so judge it on its own, and stop using any part of the oven that also shows a code.

Common causes of F4 E0

Microwave inverter that is failing
Wiring or connector problem to the inverter

✓ One safe check you can try

1. Press Cancel and stop any microwave cycle. 2. Remove food, then switch the oven breaker off for one minute and back on. 3. Try a short microwave run with a cup of water only. 4. If F4 E0 returns, stop using the microwave and call us. Never open the cabinet or the oven body.

! Why to stop there

The inverter works with very high voltage, even after the power is off.
The cause could be the inverter or its wiring, and a technician must measure to know.
You see a written quote before work, and our repair has 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.

→Same appliance

Other Wall Oven codes

Locked, Lock or LocKitchenAid Wall Oven Message "Locked": the lock feature is on PF / PF id=27 / PF id=30KitchenAid Oven Display PF, PF id=27 and PF id=30: Power failure message Please Remove and Empty ContainerKitchenAid Steam Oven Prompt Please Remove and Empty Container: End of the drain cycle Press Cancel to ResetKitchenAid Wall Oven Message "Press Cancel to Reset": clear the error, then restart Probe or Insert ProbeKitchenAid Wall Oven Code Probe or Insert Probe: Meat probe input missing PUSH or PSHKitchenAid Wall Oven Message PUSH or PSH: Press start to begin Registration ErrorKitchenAid Wi-Fi Wall Oven Message Registration Error: Check internet connection Sabbath ModeKitchenAid Wall Oven Sabbath Mode: Bake-Only operation explained

F4 E0F4 E0 questions

Does F4 E0 affect the lower oven?

The code names the microwave inverter in the upper microwave cavity. The lower oven is a separate cooking cavity, but the control is shared, so use it only if it behaves normally, and stop if more codes appear.

What is an inverter?

It supplies the microwave power in these combination units. When it, or its wiring, has a problem, the microwave cavity may not heat or may stop in the middle of a run.

Why is this rated as high?

Microwave power parts hold dangerous voltage. Because of that, we do not suggest any hands-on checks beyond a breaker reset and a short water test, and we ask owners to stop there.