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Error code reference

Samsung Air Conditioner Error Code dx

Error of electronic expansion valve close in outdoor unit (x = indoor unit address 0-F, detected more than…

Samsung codesSamsung air conditioner codes

Error of electronic expansion valve close in outdoor unit (x = indoor unit address 0-F, detected more than once).

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What dx means on a Samsung air conditioner

The dx error code on a Samsung air conditioner indicates a fault with the electronic expansion valve (EEV) in the outdoor unit, specifically that the valve has failed in the closed position. The "x" in the code represents the indoor unit address, ranging from 0 through F in hexadecimal notation, identifying which indoor unit's associated refrigerant circuit detected the fault. The condition must be detected more than once before the code is triggered, meaning the system performs a confirmation check to avoid false positives from brief transient faults.

The electronic expansion valve is a precision-controlled component that regulates the flow of refrigerant from the high-pressure liquid line into the evaporator. When the valve fails closed or sticks in the closed position, refrigerant flow to the corresponding indoor unit is blocked or severely restricted. This results in a loss of cooling or heating capacity at that indoor unit and can lead to abnormal pressure conditions in the refrigerant circuit, including high discharge pressure and low suction pressure on the compressor.

Common causes of this fault include a failed EEV coil that is no longer receiving or responding to control signals, mechanical seizure of the valve needle due to contamination or corrosion in the refrigerant circuit, wiring faults between the outdoor control board and the EEV coil, or a defective outdoor main PCB that is not generating the correct drive pulses. Because the valve is deep within the refrigerant circuit, diagnosis typically requires manifold gauge readings, coil resistance checks, and in some cases signal monitoring at the board output terminals.

Source: manufacturer service documentation.

Common causes of dx

  1. 01

    Failed EEV coil

    Part replacement

    The electromagnetic coil that drives the expansion valve can burn out or lose continuity, leaving the valve unable to open. Resistance checks on the coil terminals will reveal an open circuit or a reading outside the expected specification.

  2. 02

    Mechanical seizure of the expansion valve

    Part replacement

    Contamination, moisture, or corrosion inside the refrigerant circuit can cause the valve needle to seize in the closed position. Abnormally low suction pressure and zero superheat on the affected circuit are indicators of this condition.

  3. 03

    Wiring fault between outdoor PCB and EEV

    Wiring / connection

    Damaged, corroded, or disconnected wiring between the outdoor control board and the EEV coil connector can interrupt the drive signal. A visual inspection of the harness and continuity testing of each wire will identify this issue.

  4. 04

    Defective outdoor main PCB

    Part replacement

    If the outdoor control board is not generating the correct stepper motor drive pulses to the EEV, the valve will default to or remain in the closed position. This is typically diagnosed after confirming the coil and wiring are in good condition.

  5. 05

    Refrigerant circuit contamination

    Wiring / connection

    Non-condensables, moisture, or debris introduced during a previous service can impede valve movement or cause ice formation at the valve seat. This is often accompanied by other circuit anomalies visible on manifold gauges.

See the test procedure for each cause

Frequently asked questions about dx

What does dx mean on a Samsung air conditioner?
The dx code indicates that the electronic expansion valve in the outdoor unit has been detected in a closed or stuck-closed state for the indoor unit at address x, where x is a hexadecimal value from 0 to F. The fault must be detected more than once before the code is logged, so it reflects a confirmed and repeating condition. This valve controls refrigerant flow to the identified indoor unit, so its failure means that unit cannot properly condition the air.
Can I fix the dx error code myself?
Most of the repairs involved require handling refrigerants and working inside the outdoor unit's sealed refrigerant circuit, which requires EPA 608 certification in the United States. A homeowner can check for obvious wiring damage at the outdoor unit's service panels, but replacing the EEV coil, the valve itself, or the outdoor PCB should be performed by a certified HVAC technician. Attempting to open the refrigerant circuit without proper equipment can result in refrigerant release and personal injury.
Is it safe to keep running my air conditioner with a dx error?
Continuing to operate the system with a confirmed dx fault is not recommended. A stuck-closed expansion valve can cause abnormal pressure conditions in the outdoor unit, potentially stressing the compressor over time. The indoor unit associated with the fault address will also have little to no capacity, reducing system efficiency and comfort. It is best to address the fault promptly to avoid secondary component damage.
How much does it cost to repair a dx error on a Samsung air conditioner?
Repair costs vary depending on the root cause. Replacing an EEV coil is generally the least expensive fix, with parts and labor typically ranging from $150 to $350. If the valve body itself must be replaced, costs including refrigerant recovery, replacement, recharge, and labor can range from $400 to $900 or more. Outdoor PCB replacement adds additional parts cost on top of labor.
Will resetting the air conditioner clear the dx error code?
A power reset may temporarily clear the displayed code, but because the dx fault requires the condition to be detected more than once before triggering, it will return if the underlying hardware problem is not resolved. Resetting the system does not repair the expansion valve, its coil, or the wiring. The code should be treated as a confirmed fault requiring physical diagnosis and repair rather than a transient error that clears on its own.

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