Error code
F-DEF-SENSOR
Meaning
The defrost system cannot measure its temperature
Moderate
What to do
Why this happens
Potential causes include an open or slipped-out connector, wire damage such as cuts or shorts, abnormal sensor temperatures exceeding +65°C or dropping below -50°C, or a defective sensor.
How to fix it
This one needs a professional technician
SourceSamsung service manual