Samsung Ovens & Ranges2017–present

Error Code C-21

Temperature exceeds safe operating limits

Critical

Stop using immediately - risk of damage or safety issue

Also displayed as: C-21

What This Means

Defective oven sensor providing false high reading; Shorted sensor wire or connector; Defective broil, bake, or convection heater; Stuck relay on Main PCB; Disconnected wire harness on Main PCB

What actually causes this:

Sensor failure reporting false high temperature, stuck heating relay, or over-firing heating elements

First Thing to Check

Disconnect sensor and measure resistance; if normal, check relay operation

Parts Involved

Oven sensorHeating elementsRelaysWire harnessMain PCB

How to Fix

  1. 1

    Disconnect power and disconnect sensor harness from sensor

  2. 2

    Measure sensor resistance (should be 1080Ω at room temperature)

  3. 3

    Check resistance of broil, bake and convection heaters

  4. 4

    Check DLB, broil, bake and convection relay operation on Main PCB

  5. 5

    Check resistance of oven sensor connector on Main PCB (should be 2850Ω)

  6. 6

    Unit beeps 10 times if temperature exceeds specified limit during operation

This Error Applies To

Samsung DOC30M977D Series Ovens & Ranges (2017) (2017–present)

Service manual exact match: NQ70M7770DGService manual exact match: DOC30M977DS

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