Samsung Air Conditioner Error Code 231

Error code 231 indicates a fault in the COND OUT main temperature sensor circuit. The control board has detected a signal voltage either above 4.9V (corresponding to below -50 degrees Celsius) or below 0.4V (corresponding to above 93 degrees Celsius), both of which fall outside the valid sensor range. This typically points to a wiring break, a bad connector, or a failed sensor rather than an actual extreme temperature condition.

Operating the unit with error 231 active is not recommended. The COND OUT sensor provides data the control system uses for capacity management and protection against overheating or refrigerant issues at the condenser. Without a valid signal from this sensor, the unit cannot properly protect the compressor and related components, which risks more serious and costly damage over time.

A power reset may temporarily clear the error display, but the code will return as soon as the control board reads the sensor signal again and detects it is still out of range. Because error 231 reflects an ongoing hardware fault in the sensor circuit, the underlying wiring, connector, or sensor issue must be physically corrected before the error will stay cleared.

Some causes of error 231 are within reach of a careful DIYer. You can inspect the sensor wiring for visible damage and check that all connectors in the COND OUT sensor circuit are fully seated and free of corrosion without special tools. If the wiring and connectors look good, testing the thermistor requires a multimeter to measure resistance. Replacing a sensor or diagnosing a PCB fault is best handled by a qualified technician, especially since the work involves the refrigerant-side components of the unit.

If the fix is simply reseating a loose connector, there may be no parts cost and only a service call fee, which typically runs in the range of $75 to $150 depending on your location. Replacing the COND OUT temperature sensor itself usually costs between $20 and $80 for the part, plus labor. If the fault has caused damage to the control PCB, board replacement can range from $150 to $400 or more depending on the model.