Error code
EXT - SENSOR
Meaning
The external temperature sensor isn't sending correct readings
Moderate
What to do
Why this happens
Possible causes include an open or disconnected connector, wire damage such as cuts or shorts, a defective temperature sensor with out-of-range readings, damaged sensor wires, or an improperly seated MAIN PCB connector CN31.
How to fix it
This one needs a professional technician
SourceSamsung service manual