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Error code reference

Samsung Air Conditioner Error Code E555

Full leakage of refrigerant from outdoor unit.

Samsung codesSamsung air conditioner codes

Full leakage of refrigerant from outdoor unit.

First step from the service manual

Check compressor terminal resistance; check refrigerant pressure; check PWM valve operation.

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

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What E555 means on a Samsung air conditioner

Error code E555 on a Samsung air conditioner indicates a full refrigerant leakage condition originating from the outdoor unit. This is one of the more serious faults the system can detect, as it signals that refrigerant charge has dropped to a level where normal operation is no longer possible. The control board identifies this condition through a combination of monitored parameters, including compressor terminal resistance readings, refrigerant pressure data from the system's pressure sensors, and the behavior of the PWM (pulse-width modulation) valve in the refrigerant circuit.

When refrigerant is fully or substantially depleted, the compressor faces dramatically altered operating conditions. Running a compressor with little or no refrigerant causes inadequate lubrication and cooling of the compressor internals, which can lead to permanent mechanical damage if the system is not shut down promptly. The PWM valve, which regulates refrigerant flow rate electronically, will also behave abnormally when system pressure drops below expected thresholds, providing another diagnostic signal to the controller.

Diagnosing E555 requires checking compressor terminal resistance to rule out winding damage that may have already occurred, measuring system refrigerant pressure at both the high and low sides to confirm the loss of charge, and verifying PWM valve operation to ensure the valve itself is not causing a false reading or contributing to the leak condition. A physical inspection for leak points at fittings, coils, and line sets is also necessary before any recharge is performed.

Source: manufacturer service documentation.

Common causes of E555

  1. 01

    Refrigerant line or fitting leak

    Part replacement

    Leaks at flare fittings, solder joints, or along the copper line set are the most frequent cause of full refrigerant loss. Use a leak detector or UV dye to pinpoint the exact location before repairing and recharging.

  2. 02

    Outdoor unit coil damage or corrosion

    Part replacement

    Formicary corrosion or physical damage to the outdoor condenser coil can create pinhole leaks that gradually deplete the full refrigerant charge. Inspect the coil surface closely for discoloration, pitting, or oily residue.

  3. 03

    PWM valve failure or internal refrigerant bypass

    Part replacement

    A malfunctioning PWM valve can cause abnormal pressure readings that contribute to the E555 fault, or in some cases an internal valve failure can allow refrigerant to migrate in ways that accelerate loss. Verify valve operation as part of the diagnosis.

  4. 04

    Compressor internal leak or winding damage

    Part replacement

    If the compressor terminals show abnormal resistance readings, internal mechanical failure may have allowed refrigerant to escape into the compressor oil or atmosphere. Measure terminal-to-terminal and terminal-to-ground resistance to assess winding integrity.

  5. 05

    Pressure sensor fault giving false reading

    Part replacement

    A failed pressure transducer could report abnormally low pressure to the control board, triggering E555 even if refrigerant charge is intact. Cross-check sensor output against manifold gauge readings to confirm whether the pressure loss is real.

See the test procedure for each cause

Frequently asked questions about E555

What does E555 mean on a Samsung air conditioner?
E555 indicates a full refrigerant leakage condition detected at the outdoor unit. The system has determined, based on compressor terminal resistance, refrigerant pressure readings, and PWM valve behavior, that the refrigerant charge is critically low or fully depleted. This is a serious fault that requires professional diagnosis and repair before the system can operate safely again.
Can I fix E555 on my Samsung air conditioner myself?
This repair is not a DIY task for most homeowners. Handling refrigerant requires EPA Section 608 certification in the United States, and the diagnostic steps involve measuring compressor terminal resistance, checking system pressures with manifold gauges, and verifying PWM valve operation. A licensed HVAC technician must locate and repair the leak, then recharge the system with the correct refrigerant type and quantity.
Is it safe to keep running my Samsung air conditioner with an E555 error?
No, you should not continue operating the unit with this error active. Running the compressor without adequate refrigerant removes the lubrication and cooling that refrigerant provides to the compressor internals, which can cause permanent and costly compressor failure. Turn the system off until the leak is repaired and the system is properly recharged.
How much does it cost to repair an E555 error on a Samsung air conditioner?
Repair costs vary widely depending on where the leak is located and how much damage has occurred. A simple fitting repair and recharge may cost in the range of $200 to $600, while coil replacement or compressor replacement can run from $800 to over $2,000 including labor and refrigerant. Getting a diagnostic inspection first will give you a clearer picture of the scope of the repair.
Will resetting my Samsung air conditioner clear the E555 error?
A power reset may temporarily clear the fault code from the display, but it will not resolve the underlying refrigerant loss that triggered E555. If the refrigerant is truly depleted, the system will either fail to operate correctly or the error will return quickly. The root cause, including the leak source and any damaged components, must be identified and repaired before the system will function normally.

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