Samsung Air Conditioner Error Code P408

P408 is a low pressure sensor protection fault. It activates when suction-side refrigerant pressure falls below 3 kg/cm²G during cooling or below 0.5 kg/cm²G during heating. The unit shuts down to protect the compressor from running under abnormally low refrigerant pressure conditions.

No. The unit should not be forced to run while P408 is active. Operating a compressor under low suction pressure reduces lubrication, causes overheating of compressor internals, and can result in permanent compressor failure. Leave the unit off until the root cause has been diagnosed and corrected.

A power reset may temporarily clear the code and allow the unit to restart, but if the underlying cause has not been fixed, the low pressure condition will return and P408 will reactivate. Repeatedly resetting the unit without repairing the fault risks compressor damage. A reset is only appropriate as part of a diagnostic process after the fault has been identified and corrected.

Some steps, like cleaning a dirty air filter or checking that the indoor fan is spinning freely, can be done without special tools. However, diagnosing and correcting refrigerant charge or repairing an EEV requires EPA certification and refrigerant handling equipment. If the fault is related to refrigerant levels or valve components, a licensed HVAC technician is required.

Repair costs vary widely depending on the cause. A refrigerant leak repair and recharge typically runs anywhere from $200 to $600 or more depending on refrigerant type and leak location. An EEV replacement can range from $150 to $400 in parts and labor. A failed indoor fan motor repair generally falls between $100 and $350.