Samsung Air Conditioner Error Code Ax

The Ax error code indicates that the evaporator inlet temperature sensor on the xth indoor unit has become disconnected or has broken away from its mounting position. The x in the code represents the address of the specific indoor unit where the fault was detected. This sensor monitors incoming refrigerant temperature at the indoor coil, and the system cannot operate normally without a valid reading from it.

It is not recommended to continue running the system with this error active. Without a functioning EVAP IN sensor, the indoor unit cannot accurately regulate the refrigerant cycle, which can lead to frost buildup on the evaporator coil or other operational issues. The system may restrict or disable the affected unit to protect itself until the fault is resolved.

If the fix is simply reseating a dislodged sensor, the cost is primarily a service call fee, typically in the range of $75 to $150 depending on your area. If the sensor wire is damaged or the thermistor has failed and needs replacement, total repair costs including parts and labor generally range from $100 to $250. Costs can be higher for multi-unit systems where accessing the specific indoor unit requires additional work.

Start by identifying the indoor unit with the address number matching x in the error code. Open the indoor unit's front panel and locate the EVAP IN sensor, which is clipped against the evaporator coil near the refrigerant inlet. Firmly reseat the sensor in its mounting clip and check that its wiring connector is fully plugged in. If the sensor lead or the sensor itself appears damaged, the component will need to be replaced before the error will clear.

A simple reset will not permanently clear the Ax error if the underlying cause has not been corrected. The code will return as soon as the system powers up and attempts to read the disconnected or missing sensor. The sensor must be physically reseated or replaced, and the wiring connection verified, before the error will stay cleared.