E403, Freeze Control Error, is usually thrown when the system believes liquid flood back is occurring. Blocked filters are the number one cause of this error but, other air flow related issues, such as blocked or broken fan blades or dirty evaporator coils can also cause the error to occur. Out of range evaporator in/out sensors can also be a cause of this error. Evaporator sensors on Samsung units read 10 Kohm at 25 degrees Celsius. An EEV (electronic expansion valve) that has failed in the fully open positions could also cause an E403 error