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Error code reference

Samsung Air Conditioner Error Code E171

Indoor unit EEV open error

Samsung codesSamsung air conditioner codes

Indoor unit EEV open error – refrigerant leaks to stopped indoor unit.

First step from the service manual

Check whether EEV wire is connected correctly to indoor unit PCB; check if EEV coil is inserted correctly.

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

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What E171 means on a Samsung air conditioner

The Samsung E171 error code indicates an Electronic Expansion Valve (EEV) open error on an indoor unit, specifically caused by refrigerant migrating into a stopped indoor unit through an EEV that is failing to close properly. The EEV is a precision flow-control component that regulates refrigerant entering the indoor unit's heat exchanger. When the unit stops operating, the EEV should close to prevent refrigerant from continuing to flow into that circuit. If the valve remains open or fails to reach its fully closed position, liquid refrigerant leaks into the stopped indoor unit, disrupting system pressure balance and causing operational faults.

The most common starting point for diagnosing E171 is verifying the physical connection between the EEV wiring harness and the indoor unit PCB, as well as confirming that the EEV coil is properly seated on the valve body. A loose or incorrectly inserted coil will prevent the PCB from driving the valve through its full range of motion, leaving it in a partially or fully open state. Wiring issues such as damaged connector pins, broken wires, or incorrect harness routing can similarly interrupt the control signals needed to actuate the valve.

Beyond wiring and coil seating, the EEV stepper motor itself may have failed, or the valve body may be mechanically stuck in the open position due to contamination or internal wear. The indoor PCB is also a candidate if it is not sending the correct pulse signals to the EEV driver circuit. Diagnosing the root cause requires methodically working through the wiring, coil, and valve assembly before condemning the PCB.

Source: manufacturer service documentation.

Common causes of E171

  1. 01

    EEV coil not seated correctly

    Wiring / connection

    If the EEV coil is not fully and correctly inserted onto the valve body, the magnetic field needed to actuate the stepper valve is too weak or misdirected, preventing the valve from closing. Visually inspect and reseat the coil to confirm proper installation.

  2. 02

    Loose or faulty EEV wiring connection to PCB

    Wiring / connection

    A disconnected, corroded, or damaged connector between the EEV harness and the indoor PCB breaks the control signal path, leaving the valve uncontrolled and defaulting to an open state. Inspect the connector for bent pins, moisture intrusion, or broken wire insulation.

  3. 03

    Failed EEV stepper motor or valve assembly

    Part replacement

    Internal failure of the EEV stepper motor can prevent the valve from responding to close commands even when wiring and coil seating are correct. This typically requires replacing the EEV assembly.

  4. 04

    Mechanical obstruction or contamination in the EEV body

    Part replacement

    Debris or moisture contamination inside the valve body can cause the valve needle to stick in the open position regardless of correct electrical signals. This condition usually requires replacing the EEV.

  5. 05

    Defective indoor unit PCB

    Part replacement

    If the PCB is not generating the correct pulse signals to drive the EEV to its closed position, the valve will remain open. This should only be suspected after the wiring, coil, and EEV assembly have been ruled out.

See the test procedure for each cause

Frequently asked questions about E171

What does E171 mean on a Samsung air conditioner?
E171 indicates an indoor unit Electronic Expansion Valve open error, meaning the EEV in one of the indoor units is not closing when that unit stops operating. This allows refrigerant to leak into the stopped indoor unit, upsetting system pressure and triggering the fault. The error points to issues with the EEV coil seating, wiring connections to the PCB, the valve assembly itself, or the indoor PCB.
Can I fix the E171 error myself?
Some steps are accessible to a knowledgeable DIYer, specifically checking that the EEV coil is properly seated on the valve body and that the wiring harness is securely connected to the indoor PCB. However, if those checks do not resolve the error, diagnosing a faulty EEV stepper motor or a defective PCB requires technical knowledge and potentially specialized tools. Any work involving the refrigerant circuit must be performed by a certified HVAC technician.
Is it safe to keep running my air conditioner with an E171 error?
Continuing to operate the system with an active E171 error is not recommended. Refrigerant migrating into a stopped indoor unit disrupts system pressure balance, which can cause liquid refrigerant to reach the compressor and damage it over time. It is best to stop using the system and have it inspected promptly to avoid more costly secondary damage.
How much does it cost to repair an E171 error on a Samsung air conditioner?
Repair costs depend on the root cause. If the fix is as simple as reseating the EEV coil or reconnecting a wiring harness, costs would primarily cover the service call, typically in the range of $75 to $150. Replacing an EEV assembly generally costs between $150 and $400 including parts and labor. A defective indoor PCB replacement can range from $250 to $600 or more depending on the model and labor rates in your area.
Will resetting the air conditioner clear the E171 error?
A power reset may temporarily clear the error display, but if the underlying cause such as a misseated EEV coil, wiring fault, or failed valve is still present, the E171 code will return once the system tries to close the EEV again. A reset alone does not fix the hardware condition that triggered the fault, so a proper diagnostic inspection is necessary to resolve it permanently.

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