C-20 belongs to the same temperature-sensor failure group as C-21 and C-22 on Samsung wall ovens, but it typically points to the low end of the sensor’s reporting range — the control board is seeing a resistance value that reads as colder than physically possible, which usually means an open circuit rather than a drifting calibration.
What an open sensor circuit looks like
Samsung ovens measure cavity temperature with an RTD probe wired back to the main control board. When that circuit breaks entirely, the board cannot get a valid reading at all and defaults to the C-20 problem rather than guessing. Likely sources include:
- A sensor wire that has fully separated at a connector or splice
- A sensor probe with an internal open circuit from age or heat cycling
- A damaged wiring harness near the back of the cavity where heat exposure is highest
- A control board input that has failed and no longer registers any signal
What to try, and what to leave to a technician
Power the oven down at the breaker for about a minute before doing anything else, then restart it and attempt a normal bake to see whether C-20 clears or returns right away. Because this code most often means a broken connection rather than a soft failure, a power cycle rarely resolves it on its own, but it rules out a control board that simply needs to reboot.
The sensor and its wiring are located behind interior cavity panels and, on most models, require partial disassembly of the oven’s rear to reach safely. Testing continuity on the sensor circuit with a multimeter is the reliable way to confirm whether the probe or the harness is the broken link, and that test is best performed by someone familiar with the oven’s wiring diagram to avoid damaging insulation or other components.
Our oven repair service handles Samsung sensor and wiring diagnostics. See samsung.com/us/support for manufacturer documentation.
Independent resource — not affiliated with Samsung Electronics.
