Error Code C-21
Oven heating over — oven temperature has risen excessively, triggered at 650 F (343 C) in any cooking function except self-clean
Moderate
Address soon - your appliance may not work properly
What This Means
Failed oven temperature sensor; Shorted heater relay on Main PCB (broil, bake, or convection relay); Disconnected or damaged harness to Main PCB; Divider switch off with divider inserted
How to Fix
- 1
Disconnect power and open back cover
- 2
Measure oven sensor resistance: 1080 ohm at room temperature; reconnect or replace sensor if faulty
- 3
Check broil, bake, and convection heater resistances and relay operation (DLB, Bake relay, Broil relay — normal: infinite ohm when open)
- 4
Check harness connector CNS301 on Main PCB for full seating
- 5
Check divider switch harness at connector if divider is inserted
- 6
Repair or replace harness; replace Main PCB if relays or pattern are damaged
This Error Applies To
Samsung NX58K7850S Series Ovens & Ranges (2018) (2018–present)
Related Error Codes
Divider sensing information — Flex Duo divider insert or remove state mismatch
PCB sensor opened or shorted — oven sensor error at PCB side
Shorted key — keypad short circuit detected
Main-to-Sub communication error — continuous communication failure between Main PCB and Sub PCB
PCB ambient temperature high — safety error
Door locking information — door lock mechanism error
BLDC motor operation information — cooling fan motor or air intake motor error
Oven sensor opened (over 2950 ohm) or oven sensor shorted (under 930 ohm)