Samsung [C-20] fault codewhat it means and how to fix it

Samsung’s UK support page publishes this as the temperature sensor being open or short, and its action is four words long in effect: unplug the appliance and contact the service centre. There is no clean-it, no wait-and-retry and no reset on that page. Samsung’s own manual for the MC32D combination models is a little more generous: it describes C-20 as "temperature sensor is needed to check" and tells the owner to press Stop/Eco and operate again, and if it recurs to turn the microwave off for more than thirty seconds and try setting it again, before calling the customer care centre if it appears a third time. Read together, the two documents give you exactly one retry and then the phone.

The reason the support page skips even that is informative rather than unhelpful. An open or short circuit is not a marginal reading that might settle down; it is the sensor or its wiring being electrically broken, which does not recover. Why it matters more on a microwave than the same fault would elsewhere is worth spelling out. The cavity temperature sensor is what tells the appliance it is getting too hot, and Samsung use that reading for the code they annotate as fire sensed. A microwave that cannot read its cavity temperature has lost the input behind its own overheat protection, and continuing to use it means running an appliance whose thermal safety net is disconnected. That is why the sensible reading of Samsung’s terse instruction is that the unplugging is the point rather than a formality.

There is a second reason not to keep trying. On several Samsung models the sensor also drives automatic and sensor-based programmes, so an appliance in this state may behave oddly in ways that look like separate faults — programmes finishing early, or refusing to start — and chasing those individually wastes time when one broken circuit explains all of it. The repair itself is unremarkable: a sensor is an inexpensive part on ordinary low-voltage wiring, and the work is nothing like the high-voltage side of the appliance. The reason to have it done rather than done yourself is that reaching it means removing the outer cover.