Samsung Air Conditioner Error Code E318

Error code E318 on a Samsung air conditioner indicates a low pressure sensor breakaway fault. This means the system has detected that the low-side pressure sensor has become disconnected, lost signal continuity, or is otherwise reading outside its expected range. The low pressure sensor monitors refrigerant pressure on the suction side of the refrigerant circuit, and its data is critical for the control board to manage compressor operation, refrigerant flow, and system protection. When the sensor signal breaks away from its expected parameters, the unit interprets this as a fault condition and halts normal operation to prevent compressor damage.

A breakaway condition can result from a physical disconnection of the sensor's wiring harness, a short or open circuit in the sensor signal wire, corrosion at the connector terminals, or outright sensor failure. In some cases, vibration over time can cause the connector to work loose from the sensor body or from the control board. The sensor itself is a pressure transducer that converts refrigerant pressure into a voltage or resistance signal, so any interruption in that signal path will trigger this code.

Diagnosing E318 requires checking the wiring harness between the low pressure sensor and the main control board for continuity, inspecting connectors for corrosion or looseness, and testing the sensor output signal. If the wiring checks out, the sensor itself may need to be replaced. In rare cases, the control board input circuit for the sensor signal can fail, requiring board-level diagnosis.