Samsung Air Conditioner Error Code Ux

The Ux error code on a Samsung air conditioner indicates an EEPROM option error on an indoor unit, where the "x" in the code represents the specific indoor unit's address in a multi-zone system, ranging from 0 through F in hexadecimal notation. The EEPROM (Electrically Erasable Programmable Read-Only Memory) is a small non-volatile memory chip located on the indoor unit's main control board. This chip stores critical configuration data including unit address assignments, capacity settings, regional option codes, and system pairing information. When the indoor unit's main PCB cannot properly read, write, or verify the data stored in this chip, the Ux fault is triggered.

This error is most commonly associated with corruption of the stored configuration data, a failed or partially failed EEPROM chip, or a main control board that has suffered damage from power surge events or moisture intrusion. In multi-split systems, each indoor unit is assigned a unique address (0 through F), and a mismatch or unreadable address configuration will produce this fault specific to that unit's identifier. The error can also appear after a power interruption during a firmware or configuration write cycle, which can leave the EEPROM in a partially written and unreadable state.

Diagnosis typically centers on the indoor unit's main control PCB, since the EEPROM is soldered directly onto that board and is rarely serviceable as a standalone component. Technicians should inspect the board for visible signs of damage such as burnt components, corrosion, or swollen capacitors. If the board appears physically intact, a power reset may restore function if the fault resulted from a transient data error, but persistent Ux codes generally require replacement of the indoor unit's main control board.