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Error code reference

Samsung Air Conditioner Error Code P403

COND DOWN due to SUMP control

Samsung codesSamsung air conditioner codes

COND DOWN due to SUMP control – condensate temperature reaches 95°C; system down on 6th detection.

First step from the service manual

Check for obstacles at the air inlet/outlet of outdoor unit.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What P403 means on a Samsung air conditioner

The P403 error code on a Samsung air conditioner indicates a COND DOWN (condenser shutdown) condition triggered by SUMP control logic. Specifically, the system detects that the condensate temperature has reached or exceeded 95 degrees Celsius. This threshold is monitored continuously, and the protection logic counts each detection event. On the sixth detection, the system initiates a full shutdown to prevent heat-related damage to the compressor, refrigerant components, and associated electronics in the outdoor unit.

The SUMP control function monitors the sump or base area of the outdoor unit where condensate and liquid refrigerant can accumulate. When temperatures in this zone climb to 95C, it typically indicates that heat is not being dissipated effectively from the outdoor unit. This can result from restricted airflow at the air inlet or outlet of the outdoor unit, a dirty or blocked condenser coil, a malfunctioning condenser fan motor, or high ambient temperatures combined with poor installation clearances. The six-strike detection pattern is intentional, designed to distinguish between temporary spikes and a persistent overheating condition before forcing shutdown.

Diagnosing P403 starts with a physical inspection of the outdoor unit. Technicians should confirm that no debris, vegetation, fencing, or other obstacles are blocking the air inlet or outlet. Adequate clearance on all sides is required for proper airflow through the condenser coil. If airflow paths are clear, the next steps involve inspecting the condenser coil for fouling, checking condenser fan operation and motor current draw, and verifying that refrigerant charge and system pressures are within specification.

Source: manufacturer service documentation.

Common causes of P403

  1. 01

    Blocked air inlet or outlet on outdoor unit

    Wiring / connection

    Debris, vegetation, fencing, or other objects placed too close to the outdoor unit restrict airflow through the condenser coil, causing heat to build up rapidly. Inspect all four sides of the unit and confirm adequate clearance according to installation specifications.

  2. 02

    Dirty or fouled condenser coil

    Wiring / connection

    Accumulated dirt, dust, cottonwood seeds, or other debris clogging the condenser coil fins reduces heat transfer efficiency and drives sump temperatures up. The coil surface should be inspected and cleaned using appropriate coil cleaner and low-pressure rinsing.

  3. 03

    Condenser fan motor failure or reduced airflow

    Part replacement

    A condenser fan motor that is running slowly, intermittently, or not at all will fail to pull sufficient air across the coil, causing the sump area to overheat. Check fan blade rotation, listen for abnormal motor noise, and measure motor current draw against rated specifications.

  4. 04

    Incorrect refrigerant charge

    Part replacement

    An overcharged or undercharged refrigerant system can cause abnormal operating pressures and temperatures throughout the outdoor unit, including elevated sump temperatures. This requires pressure gauge testing and should only be performed by a certified refrigerant technician.

  5. 05

    Poor installation location with excessive ambient heat

    Wiring / connection

    Units installed in enclosed spaces, south-facing alcoves, or locations with high radiant heat exposure may repeatedly trigger this fault even without a component failure. Reviewing installation clearances and sun exposure patterns can confirm this as a contributing factor.

See the test procedure for each cause

Frequently asked questions about P403

What does P403 mean on a Samsung air conditioner?
P403 is a COND DOWN protection fault triggered when the condensate or sump temperature in the outdoor unit reaches 95 degrees Celsius. The system monitors this condition and shuts the unit down completely on the sixth detection event. It is a built-in safety mechanism designed to protect the compressor and refrigerant circuit from heat damage. The most common trigger is restricted airflow around the outdoor unit.
Can I fix P403 myself or do I need a technician?
Some causes of P403 can be addressed without professional help, including clearing obstacles from around the outdoor unit, cleaning visible debris from the condenser coil exterior, and ensuring the unit has adequate clearance on all sides. However, if the airflow paths are clear and the error persists, a technician will be needed to test the condenser fan motor, check refrigerant pressures, and inspect the temperature sensing circuit.
Will resetting the unit clear the P403 error?
Resetting the unit may temporarily clear the error and allow the system to restart, but the fault will return if the underlying cause is not corrected. The protection logic requires six detection events at 95C before forcing shutdown, so a reset only restarts that count. If the root cause is not resolved, the unit will reach its shutdown threshold again and display P403.
Is it safe to keep using my air conditioner when P403 appears?
Operating the system repeatedly through P403 shutdowns without addressing the cause is not advisable. Sustained high sump temperatures can stress the compressor and refrigerant system components, potentially leading to more costly failures. The six-detection shutdown is a protective limit, and repeatedly forcing restarts without diagnosis risks damaging components that would otherwise remain serviceable.
How much does it cost to repair a P403 error on a Samsung air conditioner?
Repair costs depend heavily on the root cause. If the fix is simply clearing debris or cleaning the condenser coil, costs may range from nothing to a modest service call fee of around 75 to 150 dollars. If the condenser fan motor needs replacement, parts and labor typically range from 200 to 450 dollars. Refrigerant-related repairs or component-level electrical diagnosis can push costs higher depending on the scope of work required.

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