Error code · Microwave

Samsung Microwave Code E-21: Temperature Sensor Open

Medium · inspection needed

Code: E-21
Appliance: Microwave
Brand: Samsung
Warranty: 30-day workmanship

What E-21 means

Samsung US microwaves with grill or convection modes show E-21 when the temperature sensor circuit reads open. The temperature sensor tells the control how hot the oven cavity is, and open means that circuit is not completing, so the control gets no usable reading. The result is a code on the display and heating modes that stay off, while the cooking itself may still be possible in a basic microwave mode.

Common causes of E-21

The temperature sensor circuit reading as open
A loose or damaged wire or connector at the sensor
Moisture near the sensor connection

✓ One safe check you can try

1. Switch the breaker off or pull the plug. 2. If moisture got in, let the oven dry out before powering it up. 3. Dry already? Wait 60 seconds before you restore power. 4. Try a short microwave cycle with a cup of water. 5. Request service when E-21 returns.

! Why to stop there

Without a temperature reading the control will not heat, so we cannot tell sensor from wiring from the control until we test.
A break that comes and goes can pass a quick check, so we test under heat.
The price is in writing before work begins.

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 Microwave codes

E-82Samsung Microwave Code E-82: Control Link Shorted E-83Samsung Microwave Code E-83: Control Link Unreliable E-X1Samsung Microwave Code E-X1: Extra Input Open E-X2Samsung Microwave Code E-X2: Extra Short Error -SE-Samsung Microwave Code -SE-: Key Short Error TESamsung Microwave Code TE: Touch Panel Communication E-52Samsung Microwave Code E-52: Memory Circuit Shorted E-53Samsung Microwave Code E-53: Memory Read or Write Failed

E-21E-21 questions

Is E-21 about microwave cooking?

The temperature sensor mostly matters for grill and convection modes. Plain microwave cooking may still run, but treat that as a stopgap, not as a sign the code is harmless.

What does open mean here?

The control sees a break in the sensor circuit instead of a normal temperature signal. It does not name the broken spot, so we trace the wire and the sensor itself.

Can I wait on this repair?

You can, if you avoid the heating modes. But a control without temperature feedback cannot guard against overheating, so do not force those modes to run.

Book a visit

Still seeing E-21?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 561-5298