Samsung Air Conditioner Error Code 271

Samsung air conditioner error code 271 indicates a fault in the SUMP temperature digital sensor circuit. The SUMP temperature sensor monitors the temperature of the sump area, which is a critical measurement point in certain refrigerant or condensate systems. The control PCB reads the sensor's output voltage continuously, and when that voltage rises above 4.95V or drops below 0.5V, the system interprets this as an open or short circuit condition respectively. A reading above 4.95V corresponds to a temperature below -30C, while a reading below 0.5V corresponds to a temperature above 151C, both of which fall outside the physically plausible operating range and signal a sensor or wiring fault rather than an actual temperature condition.

The error originates in the sensor signal circuit between the SUMP temperature sensor and the main PCB. An open circuit, such as a disconnected wire or a broken sensor element, will cause the voltage to float high toward the supply rail, triggering the over-voltage threshold. A short circuit, where the signal line contacts ground or another conductor, collapses the voltage toward zero and triggers the under-voltage threshold. Connector corrosion, damaged wiring harnesses, and failed sensor elements are the most frequent causes of these out-of-range voltage conditions.

Diagnosis should begin at the physical connection between the SUMP temperature sensor and the PCB. Inspect the connector pins for corrosion, bent terminals, or incomplete seating. Verify that the power supply line to the sensor is intact and delivering the correct reference voltage. If wiring and connections check out, resistance testing of the sensor itself can confirm whether the sensor element has opened or shorted internally. A failed sensor will need replacement, while wiring faults can often be repaired without replacing the sensor.