Samsung Oven Error Code C-21

C-21 on a Samsung oven means the oven temperature has exceeded safe operating limits, triggering a thermal protection shutdown. The control board monitors the oven temperature sensor and activates this code when readings indicate overheating. The issue can be caused by a defective temperature sensor, a stuck heating relay, or a faulty control board. The oven should not be used again until the underlying cause is identified and corrected.

No, you should not operate the oven while C-21 is active. This code indicates that the oven temperature has gone beyond safe limits, and continuing to use it could cause further component damage or create a fire hazard. Disconnect power to the oven and leave it off until the fault is diagnosed and repaired.

Repair costs depend on the failed component. An oven temperature sensor is typically the least expensive fix, with parts generally ranging from $20 to $60 and labor adding $75 to $150 if a technician is involved. A control board replacement is more costly, with parts commonly ranging from $100 to $300 or more depending on the model, plus labor. Getting a diagnostic inspection first helps avoid replacing components unnecessarily.

A knowledgeable DIYer can perform the initial sensor resistance test by disconnecting power, opening the back panel, and measuring the sensor harness resistance with a multimeter. If the reading deviates from the expected 1080 ohms at room temperature, replacing the oven temperature sensor is a straightforward repair. If the sensor tests correctly, the problem likely lies with the control board or wiring, which can be more complex to address safely.

Disconnecting power briefly may clear the code temporarily, but if the underlying component fault remains, C-21 will return as soon as the oven attempts to heat again. A reset does not repair a defective sensor, damaged wiring, or a faulty control board. Clearing the code without fixing the root cause is not a safe long-term solution.