Error Code C-21
Oven temperature control failure causing excessive heating
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: C-21
What This Means
Defective temperature sensor; Malfunctioning relay; PCB failure
What actually causes this:
Temperature sensor reading is wrong or the heating relay is stuck on, causing runaway temperature
First Thing to Check
Measure the sensor resistance with a multimeter at room temperature
Parts Involved
How to Fix
- 1
Disconnect power and open back cover
- 2
Disconnect sensor harness from control
- 3
Measure sensor resistance (should be 1080 ohms at room temperature)
- 4
Check resistance points 1, 2, 3 on main PCB
- 5
Inspect PCB for damaged components
This Error Applies To
Samsung DOB30P977D Series Ovens & Ranges (2020) (2020–present)
Related Error Codes
Temperature probe sensor short circuit detected
Steam temperature sensor open circuit detected
Drain pump failure or water sensor malfunction in steam system
Main and sub control board communication failure
A control button is stuck in pressed position
Cooling fan motor failure
PCB internal temperature sensor open circuit
Steam temperature sensor short circuit