JennAir Combination Wall Oven Code F4 E9: inverter and magnetron heat protection

What F4 E9 means

On JennAir combination wall ovens with a microwave, F4 E9 means there may be a problem with the microwave inverter or its wiring. On the older JMW2430D platform, the code is described as inverter and magnetron over-temperature, with the cooling fan, inverter and magnetron all in play. The display shows F4 E9 and the microwave stops. The microwave stops until it has cooled, and may stop again soon after.

Common causes of F4 E9

Cooling fan failing to cool the inverter and magnetron
Microwave inverter running too hot
Magnetron overheating and tripping the protection

✓ One safe check you can try

1. Press Cancel and wait at least half an hour for the microwave to cool. 2. Make sure nothing blocks the vents around the oven. 3. Reset power by turning the breaker off and on after a one-minute wait, giving the magnetron heat a second try. 4. Run a twenty-second water test. 5. If F4 E9 comes back, stop using the oven and call us about the magnetron heat.

! Why to stop there

Two costly parts are involved, so we test before we order either.
The fan is a cheaper part, and it is the first thing we check.
High-voltage parts inside the microwave must be handled by a technician.

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 Wall Oven codes

FC E9JennAir Wall Oven Code FC E9: Wi-Fi power module wiring Feature Not AvailableJennAir Wall Oven Message "Feature Not Available": Follow the Prompt on the Display Flashing Time, Clock, 12:00, Power Loss or Enter TimeJennAir Wall Oven Display Flashing Time or 12:00: Set the clock after power loss Locked, Lock or LocJennAir Wall Oven Display Locked, Lock or Loc: Controls and door are locked Press Cancel to ResetJennAir Wall Oven Message "Press Cancel to Reset": Clear and power cycle Probe or Insert ProbeJennAir Wall Oven Display Probe or Insert Probe: Meat probe needed PUSH or PSHJennAir Wall Oven Display PUSH or PSH: Press start Sabbath, Sab, 5Ab, or 5A7JennAir Wall Oven Display Sabbath, Sab, 5Ab or 5A7: Sabbath mode is on

F4 E9F4 E9 questions

How is F4 E9 different from F4 E8?

Both involve the inverter. On the older JMW2430D platform E9 adds the magnetron to the heat concern, so the checks include that part as well.

What is the likely repair?

It depends on the test. A cooling fan is the simplest, an inverter is next and the magnetron is the most expensive. We quote in writing before replacing anything.

Is the repair covered by warranty?

The work we do is covered by our 30-day workmanship warranty. We explain how it applies when we give you the price. The quote lists each part we test and replace, with a 30-day warranty on the work.