Error Code 4
Freezer defrost sensor is faulty
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: 4C
What This Means
Connector not seated at Main PCB CN30 pins 1 and 4; Wire harness damaged or disconnected; Defrost thermistor defective; Main PCB defective
What actually causes this:
Defrost sensor connector loosened or sensor element failed
First Thing to Check
Look for excessive frost buildup on the freezer evaporator coils
Parts Involved
How to Fix
- 1
1. Inspect CN30 connector pins 1 and 4
- 2
2. Measure voltage between CN30 pins 1 and 4 — normal range 4.5V to 1.0V
- 3
3. Reseat connector firmly
- 4
4. Power on and monitor for error clearance
- 5
5. If voltage out of range, replace defrost sensor
This Error Applies To
Samsung RF22N9781 Series Refrigerators (2018) (2018–present)
Related Error Codes
Freezer temperature sensor malfunction
Room temperature sensor not working
Ice maker temperature sensor failure
Fridge temperature sensor is not responding
Convertible zone temperature sensor failure
Ice storage area temperature sensor malfunction
Convertible zone defrost sensor malfunction
Internal humidity sensor not responding