Samsung Air Conditioner Error Code P401

P401 indicates that the discharge temperature sensor detected a temperature above 135°C at the compressor outlet. Samsung's control logic triggers a full system shutdown on the second detection of this condition to prevent compressor damage. The fault points to either a genuine overtemperature condition in the refrigerant circuit or a faulty discharge sensor.

No. The system will shut itself down on the second overtemperature detection specifically to protect the compressor from heat-related damage. Attempting to reset the unit and continue running it without resolving the root cause risks permanent compressor failure, which is one of the most expensive repairs on any air conditioning system.

Repair costs vary widely depending on the cause. If the fix is simply opening a closed service valve or cleaning a dirty condenser coil, costs may be limited to a service call fee, typically in the range of $75 to $200. If the system needs refrigerant, a replacement filter-drier, or a new discharge sensor, costs can range from $150 to $600 or more. A compressor replacement, in a worst-case scenario where the component has already been damaged, can cost $800 to $2,500 or higher depending on system size.

The one check a non-technician can perform is confirming that both service valves on the outdoor unit are fully open. Beyond that, diagnosing low refrigerant charge, checking pressures, inspecting the expansion valve, or replacing the discharge sensor requires refrigeration tools and certifications. It is strongly recommended to call a qualified HVAC technician for further diagnosis.

A power reset may temporarily clear the fault and allow the system to restart, but if the underlying cause is still present, the P401 code will return and the system will shut down again on the second detection. Clearing the code without addressing the root cause does not fix the problem and increases the risk of compressor damage.