Samsung Air Conditioner Error Code tu

The tu error code on a Samsung air conditioner indicates a fault with the indoor unit room temperature sensor, specifically an open circuit or short circuit condition. This sensor is a negative temperature coefficient (NTC) thermistor that continuously monitors the ambient air temperature inside the room and sends resistance-based signals to the indoor unit control board. When the board detects that the sensor's resistance has fallen outside the expected operating range, either dropping near zero (short) or rising to an open circuit state, it triggers the tu fault and typically halts normal cooling or heating operation.

An open circuit fault means the thermistor or its wiring has lost continuity, preventing any signal from reaching the control board. A short circuit fault means the sensor or wiring has collapsed to near-zero resistance, sending an invalid temperature reading. Both conditions cause the control board to lose the ability to regulate the system accurately. Common triggers include physical damage to the sensor harness, corrosion at the connector pins, moisture intrusion into the sensor housing, or outright thermistor failure due to age and thermal cycling.

Diagnosing the tu code requires inspecting the room temperature sensor and its wiring harness visually for damage, then using a multimeter to measure the thermistor's resistance at a known ambient temperature and comparing the reading against the expected NTC curve for that sensor. If the resistance reads open line (OL) or near zero ohms, the sensor itself has failed and requires replacement. Connector corrosion can sometimes be cleaned to restore proper contact, but a failed thermistor must be replaced to clear the fault.