What F4 E3 Means
Built-In Microwave, including the microwave-oven combination: KitchenAid publishes for F4 E3 "There may be a problem with the Microwave Exhaust Air Temperature Sensor, or the associated wiring." The exhaust air sensor is how the appliance knows the air it is pushing out is at a sensible temperature. That is a protection measurement: it is the reading that would tell the control the cabinet is running hot. A fault against it means the appliance has lost that check.
Common Causes of F4 E3
- An exhaust air temperature sensor failed or out of range
- Sensor wiring damaged in the exhaust path
- A control channel no longer reading the sensor
🔧 One Safe Check You Can Try
Let the appliance cool and keep the door shut, then cut power at the breaker rather than reaching behind a built-in cabinet for a plug: power the unit down by switching off the circuit breakers for one minute, power it back up, watch the oven for one minute to see whether the code returns, and verify the oven operates.
⚠ Why You Shouldn't Go Further Than That
- Losing a thermal protection reading is not the same as losing a convenience, because the appliance can no longer tell you, or itself, that it is overheating.
- Everything in this appliance beyond the door and the control panel sits alongside a capacitor that stays charged after the plug is pulled, which is why the published owner procedure stops at the breaker.
- A part swapped without a measurement is a part that may well come out again, and the labour is charged either way.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.