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Error code reference

Samsung Air Conditioner Error Code E557

Indoor unit EEV close error (2nd detection)

Samsung codesSamsung air conditioner codes

Indoor unit EEV close error (2nd detection) - persistent electronic expansion valve close failure.

First step from the service manual

Check whether the EEV wire is connected to the indoor unit PCB correctly.

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

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What E557 means on a Samsung air conditioner

Error code E557 on a Samsung air conditioner indicates a persistent electronic expansion valve (EEV) close failure, specifically flagged as a second detection event. The EEV is a motorized valve in the indoor unit that controls refrigerant flow into the evaporator coil by opening and closing in precise increments. When the control system commands the valve to close and the valve fails to respond or confirm closure, the unit logs an initial error. If the condition persists or recurs, the system escalates to E557, signaling that the close failure is not an isolated glitch but a repeating fault requiring attention.

The EEV relies on a stepper motor driven by pulse signals from the indoor unit PCB. If the wiring harness between the PCB and the EEV is loose, damaged, or improperly connected, the motor will not receive the signals needed to drive the valve to the closed position. Beyond wiring issues, the valve itself can fail mechanically due to a seized or worn stepper motor, a stuck valve needle, or internal contamination from debris or moisture in the refrigerant circuit. In some cases, the PCB output driver responsible for sending pulses to the EEV may be faulty, causing the valve to receive no signal even when connections are intact.

Because this is a second-detection error, the system has already attempted to recover from an initial EEV close fault and has determined that the problem is ongoing. This means intermittent causes such as a momentarily loose connector are less likely, and a more definitive component or wiring fault is the probable source. Diagnosis should start at the wiring harness connection on the indoor PCB and work systematically toward the valve itself.

Source: manufacturer service documentation.

Common causes of E557

  1. 01

    Loose or disconnected EEV wiring harness

    Wiring / connection

    The wire connector between the EEV and the indoor unit PCB may be loose, unplugged, or improperly seated. This is the first thing to check, as it is the most common cause and requires no parts to correct if the connector is simply reseated.

  2. 02

    Damaged or broken EEV wiring

    Part replacement

    The wiring harness leading to the EEV can develop breaks, shorts, or chafing damage, especially if routed near sharp edges or moving components. Inspect the full length of the wire for visible damage and test continuity.

  3. 03

    Failed EEV stepper motor

    Part replacement

    The stepper motor inside the expansion valve can seize or burn out, preventing the valve from responding to close commands from the PCB. A failed motor typically requires replacement of the EEV assembly.

  4. 04

    Mechanically stuck or contaminated valve

    Part replacement

    Debris, moisture, or refrigerant oil contamination inside the refrigerant circuit can cause the valve needle to stick in an open position. This condition may also point to broader refrigerant circuit contamination issues.

  5. 05

    Faulty indoor unit PCB

    Part replacement

    If the PCB output driver circuit responsible for sending pulse signals to the EEV has failed, the valve will not receive close commands regardless of wiring integrity. This is typically diagnosed after wiring and the valve itself have been ruled out.

See the test procedure for each cause

Frequently asked questions about E557

What does E557 mean on a Samsung air conditioner?
E557 indicates a persistent electronic expansion valve (EEV) close error that has been detected for the second time. The EEV is a motorized valve inside the indoor unit that regulates refrigerant flow, and this code means the system has commanded the valve to close but the valve has failed to do so on repeated attempts. The unit flags this as a second-detection event to distinguish it from a one-time glitch.
Can I fix E557 on my Samsung air conditioner myself?
The first diagnostic step, checking that the EEV wiring harness is properly connected to the indoor PCB, is something a technically confident homeowner may be able to perform after safely disconnecting power. However, if the wiring is intact, further diagnosis involves testing the EEV motor, refrigerant circuit components, and the PCB, all of which typically require a qualified HVAC technician with the proper tools and refrigerant handling certification.
Is it safe to run my Samsung air conditioner with an E557 error?
Running the unit with E557 active is not recommended. A stuck-open EEV can allow uncontrolled refrigerant flow into the evaporator, which may cause the coil to freeze over or lead to liquid refrigerant entering the compressor, potentially causing serious compressor damage. It is best to turn the unit off until the fault is diagnosed and corrected.
Will resetting the air conditioner clear the E557 error?
A power reset may temporarily clear the error display, but because E557 is specifically a second-detection fault, the underlying problem has already persisted through at least one recovery attempt. If the wiring or component fault is not repaired, the code will return once the system restarts and attempts to operate the EEV again.
How much does it cost to repair an E557 error on a Samsung air conditioner?
Repair costs depend on the root cause. If only a loose wiring connector needs to be reseated, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the EEV assembly requires replacement, parts and labor combined can range from $200 to $600 or more depending on the unit model and local labor rates. PCB replacement is generally at the higher end of that range.

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