Error code
C-20
Meaning
Oven sensor opened
Moderate
What to do
Why this happens
The issue may stem from oven sensor resistance exceeding 20 ohms at room temperature, a disconnected or damaged sensor harness, damage to terminals or wires on the harness, or problems with the oven sensor connector on the main PCB.
SourceSamsung service manual - 30" Freestanding Self-Cleaning Electric Range