Samsung Air Conditioner Error Code E271

The E271 error code on a Samsung air conditioner indicates a fault in the SUMP temperature digital sensor circuit. Specifically, the unit has detected a voltage reading that is either above 4.95V or below 0.5V on the sensor signal line. This out-of-range voltage tells the control board that the sensor circuit is in an open or short condition, meaning the sensor is either disconnected from the circuit entirely or has an internal short causing abnormal resistance. The fault detection is active only when the outdoor ambient temperature is above -10°C, which prevents false triggers from extreme cold where sensor behavior can shift naturally.

The SUMP temperature sensor monitors the temperature of the sump area in the outdoor unit, which is the lower section where refrigerant oil and liquid refrigerant can collect. Accurate sump temperature data is critical for proper compressor protection and system operation. When the sensor fails to report a valid signal, the unit halts normal operation to prevent potential compressor damage from running under unmonitored thermal conditions.

The most productive first step is to inspect the wiring harness and connector at the SUMP temperature sensor. Look for loose connector pins, corrosion on the terminals, damaged wiring insulation, or a completely disconnected power or signal line. If the connections appear intact, the sensor itself should be tested for correct resistance output at a known temperature. A failed sensor will typically read near zero ohms (short) or infinite resistance (open), both of which produce the out-of-range voltage the control board is detecting.