Error Code 1
Freezer temperature sensor is open, shorted, or disconnected
Critical
Stop using immediately - risk of damage or safety issue
Also displayed as: F and R LEDs blink (item 1)
What This Means
Disconnected or loose sensor connector at CN51; Open or shorted thermistor element; Damaged wiring harness to freezer sensor; Failed MAIN PCB sensor input circuit
What actually causes this:
The thermistor in the freezer has failed or its wiring has come loose, so the control board cannot read the freezer temperature
First Thing to Check
Open the freezer and look for the sensor connector near the evaporator cover — make sure it is firmly plugged in
Parts Involved
How to Fix
- 1
Check voltage at MAIN PCB CN51 pin 9 to pin 11; should be 4.5V to 1.0V
- 2
Verify CN51 connector is fully seated
- 3
Measure resistance of freezer sensor and compare to temperature table (DATA1)
- 4
If sensor resistance is out of range, replace sensor; if voltage is wrong with good sensor, check harness and PCB
This Error Applies To
Samsung RF18A5101 Series Refrigerators (2021) (2021–present)
Related Error Codes
Fridge compartment defrost sensor is faulty or disconnected
Fridge temperature sensor is open, shorted, or disconnected
Ice maker temperature sensor in freezer is faulty or disconnected
Freezer defrost heater or its protection device has failed
Freezer defrost sensor is faulty or its protective bimetal/fuse has opened
Humidity sensor is faulty or disconnected
Fridge compartment defrost heater or protection device has failed
External ambient temperature sensor is open, shorted, or disconnected