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Error code reference

KitchenAid Microwave Error Code E1

Temperature sensor opened (when displayed on upper/left side) or temperature sensor shorted (context…

KitchenAid codesKitchenAid microwave codes

Temperature sensor opened (when displayed on upper/left side) or temperature sensor shorted (context dependent).

First step from the service manual

Check sensor connection, then measure sensor resistance (1080 ohms at 70°F, add 2 ohms per degree). If resistance is not valid, replace sensor. If sensor resistance and connections are good, oven cavity temperature may have exceeded safe level — check for welded-closed relays on the control.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E1 means on a KitchenAid microwave

The E1 error on a KitchenAid microwave indicates the control board has detected a fault with the temperature sensor circuit. When displayed on the upper or left side of the display, E1 specifically points to an open temperature sensor, meaning the circuit is broken and no signal is reaching the control. In some configurations, E1 can also indicate a shorted sensor, where resistance has dropped to an abnormal level. The temperature sensor is a thermistor that should read approximately 1080 ohms at 70°F, increasing roughly 2 ohms per degree Fahrenheit. When the control board reads a resistance value outside the expected range, or receives no signal at all, it throws E1 and halts operation.

For homeowners, the temperature sensor is a small component inside the oven cavity that monitors heat levels during cooking. When it fails or its wiring comes loose, the microwave cannot safely track internal temperatures and shuts down to protect itself and your kitchen.

If the sensor checks out electrically, the cavity may have overheated due to a relay on the control board welding itself in the closed position, keeping the magnetron running longer than intended. This makes the relay a serious secondary suspect when sensor resistance and connections both test good.

Source: manufacturer service documentation.

Common causes of E1

  1. 01

    Failed temperature sensor (thermistor)

    Part replacement

    The thermistor has drifted out of spec, gone open, or shorted internally. When measured, resistance will fall outside the expected range based on the 1080-ohm baseline at 70°F, causing the control to log E1.

  2. 02

    Loose or damaged sensor wiring connection

    Wiring / connection

    The connector between the temperature sensor and the control board has come loose, corroded, or developed a break in the wire. This creates an open circuit that the control board reads as a failed sensor even if the thermistor itself is functional.

  3. 03

    Welded-closed relay on the control board

    Part replacement

    A relay on the control board has welded shut, causing the magnetron to run continuously and drive oven cavity temperature beyond safe limits. The temperature sensor trips E1 as a result of the overtemperature condition rather than a sensor failure itself.

  4. 04

    Defective control board

    Part replacement

    If the sensor resistance measures correctly and all wiring connections are secure, the control board itself may be misreading the sensor signal due to a failed input circuit on the board.

See the test procedure for each cause

Frequently asked questions about E1

What does E1 mean on a KitchenAid microwave?
E1 means the control board has detected a problem with the temperature sensor circuit. Depending on where the code appears on the display, it indicates either an open temperature sensor (broken circuit) or a shorted one. The sensor should measure around 1080 ohms at 70°F, and the control flags E1 when the reading falls outside the expected range.
How do I fix E1 on a KitchenAid microwave?
Start by unplugging the microwave and inspecting the wiring connector at the temperature sensor for looseness or corrosion. Then measure the sensor's resistance with a multimeter. At 70°F it should read approximately 1080 ohms, adding about 2 ohms per degree above that. If resistance is out of range, replace the sensor. If the sensor and wiring both check out, inspect the control board for a relay that may have welded closed, as this can cause overtemperature conditions that trigger E1.
Is it safe to use my KitchenAid microwave when E1 is displayed?
No. The microwave has stopped normal operation because it cannot reliably monitor internal temperature. Running it in this state risks overheating, especially if a welded relay is the underlying cause. Do not bypass or ignore the error until the fault is diagnosed and repaired.
How much does it cost to fix E1 on a KitchenAid microwave?
If only the temperature sensor needs replacing, the part typically costs between $20 and $60 depending on the model, and the repair is manageable for a careful DIYer comfortable working with appliances after unplugging them. If the control board needs replacement due to a welded relay or failed input circuit, the part alone can run $100 to $250 or more, making professional diagnosis worthwhile before purchasing the board.
Can a loose wire cause E1 on a KitchenAid microwave?
Yes. A disconnected or corroded connector at the temperature sensor creates an open circuit that the control board interprets as a failed sensor, triggering E1 even when the thermistor itself is in good condition. Always check the sensor wiring connection before purchasing a replacement part.

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