E21 is an open and E22 a short in the thermal sensor circuit; sensor, control board or wiring may be to blame.
Model compatibility: KitchenAid reuses codes across series and model years, so E21 / E22 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
The thermal sensor circuit reported an open (E21) or a short (E22) to the control board.
Both E21 and E22 concern the thermal sensor circuit of a KitchenAid over-the-range microwave. The manufacturer lists three possibilities for each: the thermal sensor, the appliance control board and the wiring between parts.
E21: the circuit reported an open to the control board.
E22: the circuit reported a short to the control board.
Open versus short
As a general description, an open circuit is a break in the path where current should flow, and a short circuit lets current take a route it was not meant to take. In both cases the control receives a reading it cannot use. This is why the sensor, the board that reads it and the wiring in between show up in each entry.
Reset listed by KitchenAid
Turn off the breaker(s) for the microwave. Wait a full minute.
Turn the breaker(s) on.
Stay with the microwave for a minute to confirm the code does not return.
Check operation.
Beyond the reset
No other owner step is given for either code; the pages direct you to call or schedule service. The possible causes include a control board and wiring inside the cabinet, so leave that to a technician, and keep the cabinet closed because of the high-voltage parts.
Remember which code appeared
The source keeps the two codes apart, since one is an open and the other a short. Note whether you saw E21 or E22.
Nearby codes
E24: an overheat condition, and the thermal sensor is one possible cause
E23: pre-heat temperature not reached within thirty minutes
E61, E62 and E63: the oven sensor circuit reporting open or shorted
Thermal sensor repair in Los Angeles
If the breaker reset does not clear E21 or E22, KitchenAid microwave repair in Los Angeles can be arranged on (310) 363-8964. Give the code and the model number.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your KitchenAid appliance?
Book a specialist visit for a clear estimate and approval before any repair.
