Editorial & technical review
- Written by ApplianceWorth Editorial Team
- Technically reviewed by Victor — appliance technician
- Last reviewed 2026-07-01
- Applies to Samsung microwaves
- Confidence medium
- Also displayed as C20, C21, C22, E21
- Sources Manufacturer service documentation and field-repair experience · Methodology · Report a correction
What this code means
The microwave or convection section detected an open, shorted or abnormal temperature-sensor circuit.
Most likely causes
- A failed cavity or convection temperature sensor
- A loose or heat-damaged sensor connector
- A control-board input fault
- Overheating caused by restricted ventilation
Safe checks for the owner
- Unplug the microwave and let it cool.
- Check that external vents are not blocked and the installation has required clearances.
- Do not remove the cabinet or test internal components.
Estimated U.S. repair cost
$280–$580, depending on model, access, parts availability and local labor.