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Error code reference

Samsung Air Conditioner Error Code 438

EVI EEV opening error.

Samsung codesSamsung air conditioner codes

EVI EEV opening error.

First step from the service manual

Check if there is any problem with EVI EEV connector/coil mounted in the right position; check if there is any problem with the valve.

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

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What 438 means on a Samsung air conditioner

Error code 438 on a Samsung air conditioner indicates an EVI EEV opening error. EVI stands for Enhanced Vapor Injection, a refrigerant circuit feature used in heat pump systems to improve efficiency at low ambient temperatures. The EEV (Electronic Expansion Valve) in this circuit controls the flow of refrigerant injected into the compressor mid-stage. When the control board detects that this valve is not opening correctly or is not responding as expected, it triggers the 438 fault code.

The most common trigger points for this error are mechanical or electrical faults at the valve itself or its associated wiring harness. The EVI EEV coil must be properly seated and connected for the valve to receive the drive signal from the control board. If the coil is loose, misaligned, or has a damaged connector, the board will not be able to actuate the valve, resulting in this error. The valve body itself can also develop internal faults such as a stuck or seized needle, which prevents proper opening regardless of the electrical signal.

Diagnosing this fault should begin by physically inspecting the EVI EEV coil and its mounting position on the valve body. Confirm the connector is fully seated and free of corrosion or pin damage. If the coil and wiring check out, the valve body itself should be tested or replaced. Because this component is part of the refrigerant circuit, any work involving valve replacement will require a certified technician with refrigerant handling credentials.

Source: manufacturer service documentation.

Common causes of 438

  1. 01

    EVI EEV coil improperly mounted or misaligned

    Wiring / connection

    If the coil is not correctly seated on the valve body, it cannot generate the magnetic field needed to actuate the valve. Inspect the coil position and confirm it is fully and squarely mounted.

  2. 02

    Damaged or loose EEV connector

    Wiring / connection

    A disconnected, corroded, or damaged wiring connector at the EVI EEV will prevent the control signal from reaching the coil. Check the connector for bent pins, moisture intrusion, or incomplete seating.

  3. 03

    Failed EVI EEV coil

    Part replacement

    The coil can burn out or develop an open circuit, making it unable to drive the valve even if the connector and wiring are intact. A coil resistance check can confirm whether the coil has failed.

  4. 04

    Stuck or seized EVI EEV valve body

    Part replacement

    The valve needle can become stuck in the closed position due to debris, corrosion, or mechanical wear. If the coil and wiring are confirmed good but the valve does not open, the valve body itself may need replacement.

  5. 05

    Control board unable to drive the EEV

    Part replacement

    If the board's EEV driver circuit is faulty, it will not send the correct signal to open the valve. This is less common but should be considered after ruling out the valve, coil, and wiring.

See the test procedure for each cause

Frequently asked questions about 438

What does 438 mean on a Samsung air conditioner?
Error code 438 indicates an EVI EEV opening error. The EVI (Enhanced Vapor Injection) Electronic Expansion Valve is not opening as expected, which disrupts refrigerant flow in a specialized injection circuit. This fault typically points to a problem with the valve coil, its connector, or the valve body itself.
Can I fix error code 438 myself?
Some basic checks, such as verifying that the EEV coil is properly mounted and that the connector is fully seated and undamaged, can be performed without specialized tools. However, if the valve body itself has failed, replacement involves the sealed refrigerant system and requires a certified HVAC technician. Attempting to open refrigerant lines without certification is unsafe and illegal in most regions.
Is it safe to run my Samsung air conditioner with error code 438 active?
Continuing to run the unit with this error is not recommended. The EVI circuit is part of the refrigerant system, and operating with a malfunctioning expansion valve can stress the compressor and other components. Turn off the unit and schedule a service call to prevent further damage.
Will resetting the air conditioner clear error code 438?
A power reset may temporarily clear the fault display, but the error will return if the underlying problem with the EVI EEV is not resolved. The valve, coil, and connector need to be physically inspected and repaired or replaced before the system will operate without triggering the code again.
How much does it cost to repair error code 438 on a Samsung air conditioner?
Repair costs vary depending on the root cause. If only the coil or connector needs replacement, costs are generally lower, typically in the range of $100 to $300 including labor. If the valve body requires replacement and refrigerant recovery and recharge are involved, costs can rise to $300 to $700 or more depending on the technician's rates and refrigerant prices in your area.

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