What F4 E3 Means
Wall Oven and Combination Wall Oven: this code belongs to the microwave half of a combination appliance - the cavity that has a microwave in it as well as an oven. F4 E3 carries the sentence that there may be a problem with the microwave exhaust air temperature sensor, or the associated wiring. That sensor measures the temperature of air leaving the microwave cavity, which is how the appliance knows whether it is shedding heat properly. A reading it cannot accept means it has lost a measurement it uses to protect itself, so it stops rather than run without it. KitchenAid adds a note to the pages in this family that is worth knowing: the error code may display in F# E# format or in E# F# format, so the same fault can appear with the two halves swapped.
Common Causes of F4 E3
- The exhaust air temperature sensor open, shorted or drifted out of range
- The wiring to that sensor damaged or disconnected
- Genuinely restricted exhaust airflow producing readings the control rejects
🔧 One Safe Check You Can Try
Let the cavity cool with the door closed before you do anything. An oven that has just been cooking holds enough heat to burn through a cloth, and a self-clean cycle leaves it far hotter than that. Before the reset, check the obvious external thing: that the vents on the appliance are not blocked by foil, a cloth, stored trays or a cabinet fitted too tightly, since restricted exhaust is what this sensor exists to notice. Then power the oven down by switching off its circuit breakers for one minute, power it back up, watch it for one minute to be sure the code does not return, and verify the oven operates.
⚠ Why You Shouldn't Go Further Than That
- A microwave stores energy in its high-voltage capacitor, and that charge does not drain when the power goes off, so the inside of the microwave half stays dangerous long after the breaker has been switched.
- The sensor named here is part of how the appliance decides whether it is overheating, so running it with that measurement in doubt removes a protection rather than an indicator.
- The sensor sits in the exhaust path inside the housing, reached only by taking the whole combination appliance out of the cabinet opening.
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.