What does Samsung C-20 Error Code - Causes & Fix mean?

C-20 means a sensor fault in your Samsung microwave. Reset by unplugging 30+ seconds. If it returns, check or replace the thermistor.

How do I fix Samsung C-20 Error Code - Causes & Fix?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with 20 active?

Generally no. Faults on Appliance units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for Samsung C-20 Error Code - Causes & Fix?

The most frequently replaced parts for Samsung C-20 Error Code - Causes & Fix are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is Samsung C-20 Error Code - Causes & Fix a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

Samsung C-20 Error Code - Causes & Fix

Samsung C-20 Error Code — What It Means

The C-20 code indicates a problem in the temperature sensor circuit. Samsung groups C-20, C-21, and C-22 as sensor malfunctions. The control board has detected an out-of-range signal from the oven cavity thermistor or an open or shorted sensor input. This fault will prevent the microwave from running normally until the sensor circuit is restored.

Jump to Fix

Common Causes

Failed temperature sensor The thermistor inside the oven cavity has opened, shorted, or drifted out of the expected resistance range.
Loose or corroded sensor connector The plug between the sensor harness and the control board has backed out, collected moisture, or developed oxidation.
Damaged sensor wiring The wire between the thermistor and the control board is pinched, broken, or melted.
Main control board input fault The PCB sensor input circuit has failed even though the thermistor and wiring test normal.

Step-by-Step Fix

Unplug the microwave and wait at least 30 seconds to clear the fault memory, then reconnect power and test whether the code returns.
Disconnect power again and remove the outer cabinet panels to access the control board and sensor wiring.
Locate the temperature sensor (a small bead thermistor with two wires, usually clipped or taped to the oven cavity wall or waveguide cover).
Inspect the sensor connector where it plugs into the control board or harness and reseat it firmly, checking for corrosion or bent pins.
Test the sensor with a multimeter set to ohms. A typical thermistor will show finite resistance (not open or shorted) and the reading should change smoothly when you warm the sensor bead between your fingers.
Replace the temperature sensor if it reads open circuit, short circuit, or does not change resistance with temperature, then reassemble and retest.
Replace the main control board if the sensor and all wiring test good but the C-20 code persists after a reset.

Parts Often Needed

Part	Notes
Samsung microwave temperature sensor / thermistor	Amazon \| Match your model number. The sensor is a two-wire bead or probe clipped to the cavity.
Main control board / PCB	Amazon \| Only if the sensor circuit tests normal and the code returns after reset.

When to Call a Pro

If you are uncomfortable working inside a microwave cabinet or using a multimeter to test resistance, call a technician. Microwaves store high voltage in the capacitor even when unplugged, so proper discharge and safety procedures are essential. If you have replaced the sensor and the code returns immediately, the control board input circuit is likely at fault and a professional can confirm the diagnosis and source the correct board for your model.