Samsung Air Conditioner Error Code P404

P404 indicates that the low pressure switch has detected refrigerant suction pressure below 1.2 kg/cm²G, which is the minimum safe operating pressure for the compressor. When this threshold is crossed, the unit shuts down to prevent compressor damage. If the condition is detected a second time, the system enters a full lockout state and will not restart without manual intervention.

No. The P404 error means the system has already shut itself off to protect the compressor. Attempting to bypass or ignore this fault and force operation with low refrigerant pressure can cause the compressor to run unlubricated, leading to permanent compressor failure. Leave the unit off until the underlying cause is diagnosed and corrected.

Repair costs vary widely depending on the cause. Confirming open service valves costs nothing, while replacing a faulty low pressure switch typically runs in the range of $100 to $250 including labor. A refrigerant leak repair combined with recharging the system can range from $200 to $600 or more depending on leak location and refrigerant type. Compressor replacement, if damage has already occurred, can cost $800 to $2,000 or higher.

Some steps can be checked without special tools, including confirming that both service valves are fully open and inspecting the evaporator coil for ice or heavy fouling. However, diagnosing a refrigerant leak, testing the low pressure switch, or recharging the system requires EPA certification and professional equipment. Most P404 repairs beyond valve checks should be handled by a licensed HVAC technician.

A reset may temporarily clear the fault display, but the error will return if the underlying pressure problem has not been resolved. After two detections of the low pressure condition, the system enters a locked shutdown state that will not clear until the root cause is addressed. Repeated resets without fixing the problem risk compressor damage.