Error Code 21C
Freezer evaporator fan not running or not sending feedback signal
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: 21C
What This Means
Feedback signal line contact error; Motor wire separation or open circuit; Defective BLDC fan motor; Frozen fan blades due to frost buildup
What actually causes this:
Fan motor seized from ice buildup on blades, or fan motor winding failed.
First Thing to Check
With power off, manually spin the freezer fan blade through the evaporator cover — if it is stiff or blocked by ice, defrost the freezer first.
Parts Involved
How to Fix
- 1
Run Forced Operation to confirm fan behavior
- 2
Check feedback signal between Main PCB CN20 pins 14 and 18; fan running correctly produces a specific frequency pulse
- 3
Check drive voltage between CN20 #16 and #18 (should be DC 7–12V when fan commanded on)
- 4
Check pulse signal at CN20 #14 (F-FAN feedback) for presence when motor spins
- 5
Verify door switches are closed (open door suppresses fan)
This Error Applies To
Samsung RF29CB9900 Series Refrigerators (2023) (2023–present)
Related Error Codes
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Internal I/O expander chip on Main PCB has lost communication
Ambient air temperature sensor reading invalid
Freezer defrost sensor reading out of valid range
Flex Crisper compartment sensor out of valid range
Fridge compartment defrost sensor reading out of valid range
Fridge evaporator fan not running or not sending feedback
FlexZone fan not running or not sending feedback signal