Samsung Air Conditioner Error Code E558

E558 indicates a persistent Electronic Expansion Valve open error that has been detected for the second time. The EEV, which controls refrigerant flow into the indoor unit, is stuck open and cannot be commanded closed by the indoor PCB. This allows refrigerant to continue entering a stopped indoor unit, which can cause coil icing and system pressure imbalances. The unit shuts down to prevent further damage until the fault is resolved.

No, you should not continue operating the unit with E558 active. An EEV stuck open allows uncontrolled refrigerant flow into a stopped indoor unit, which can cause ice accumulation on the evaporator coil and create abnormal pressure conditions throughout the refrigerant circuit. Continued operation in this state risks compressor damage and can worsen what might otherwise be a minor wiring or valve fault.

Repair costs depend on which component has failed. If the issue is simply a loose wiring harness connection, a service call to diagnose and correct it might cost between $75 and $150. Replacing an EEV coil assembly typically ranges from $100 to $250 including parts and labor. If the valve body itself or the indoor PCB requires replacement, costs can range from $200 to $600 or more depending on the unit model and local labor rates.

The first diagnostic step, checking whether the EEV wiring harness is properly connected to the indoor PCB, is something a knowledgeable DIYer can perform safely with the unit powered off. However, if the wiring checks out and the fault points to a failed EEV coil, a stuck valve body, or a damaged PCB, those repairs involve refrigerant circuit components and should be handled by a certified HVAC technician. Working on the refrigerant side of the system requires proper certification and equipment.

A power reset is unlikely to permanently clear E558 because it is classified as a second-detection fault, meaning the system has already encountered and logged this condition more than once. While a reset may temporarily clear the code, it will return quickly if the underlying cause, such as a loose EEV connector, failed coil, or stuck valve, has not been corrected. The root cause must be repaired for the fault to be resolved.