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Error code reference

Samsung Air Conditioner Error Code *A

Indoor and outdoor unit communication error (wired remote controller; * = indoor unit address).

Samsung codesSamsung air conditioner codes

Indoor and outdoor unit communication error (wired remote controller; * = indoor unit address).

First step from the service manual

Check communication cables and PCBs of indoor and outdoor units.

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

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What *A means on a Samsung air conditioner

The *A error code on a Samsung air conditioner indicates a communication failure between an indoor unit and the outdoor unit when using a wired remote controller. The asterisk in the code represents the specific indoor unit address, meaning the number displayed in place of the asterisk identifies exactly which indoor unit in the system has lost communication with the outdoor unit. This is a serial communication error, meaning the data signal transmitted along the communication wiring between units has been interrupted or corrupted.

The communication circuit in a multi-zone or ducted Samsung system relies on a continuous, clean data signal passing through dedicated communication cables between the indoor PCB, the wired remote controller, and the outdoor unit PCB. Any break, short, or impedance mismatch in this wiring path will trigger the *A fault. The PCBs on both ends of the communication line contain microcontrollers and signal processing components that must successfully exchange data packets. If either board is damaged or the signal never arrives, the system logs the fault and disables operation for that indoor unit address.

Common triggers include physical damage to communication cables, loose terminal connections at either unit, water ingress into electrical compartments causing corrosion on connector pins, and PCB component failures on the indoor or outdoor board. Power surges can damage the communication circuitry on one or both PCBs without visibly burning components. Diagnosing this code requires systematically checking the wiring continuity and terminal integrity first, then evaluating PCB function if the cabling is confirmed good.

Source: manufacturer service documentation.

Common causes of *A

  1. 01

    Loose or disconnected communication cable terminals

    Wiring / connection

    Vibration during operation can loosen the screw terminals or push-in connectors where communication cables attach at both the indoor and outdoor units. Inspect all terminal blocks for secure seating and retighten any loose connections.

  2. 02

    Damaged or broken communication cable

    Part replacement

    The cable running between the indoor and outdoor units may be pinched, cut, or corroded, interrupting the data signal. Use a multimeter to check continuity along each conductor of the communication wire.

  3. 03

    Corroded or contaminated connector pins

    Wiring / connection

    Water intrusion into the electrical compartment of either unit can corrode the connector pins on the communication terminals, increasing resistance and breaking the data link. Look for rust, green oxidation, or moisture staining around the connectors.

  4. 04

    Failed indoor unit PCB

    Part replacement

    The indoor unit control board may have suffered a component failure in its communication circuitry, preventing it from sending or receiving signals. If wiring checks out, the indoor PCB should be tested and likely replaced.

  5. 05

    Failed outdoor unit PCB

    Part replacement

    The outdoor unit main PCB handles communication with all connected indoor units, and a failure in its communication circuit will cause one or multiple indoor units to show the *A error. If multiple indoor units show the fault simultaneously, the outdoor board is the more likely culprit.

See the test procedure for each cause

Frequently asked questions about *A

What does *A mean on a Samsung air conditioner?
The *A error code indicates a communication failure between a specific indoor unit and the outdoor unit when using a wired remote controller. The number shown in place of the asterisk identifies which indoor unit address is affected. The system has lost the data signal it needs to coordinate operation between the two units, so that indoor unit will not run until communication is restored.
Can I fix the *A error myself?
Some causes of the *A error are accessible to a knowledgeable DIYer. You can inspect and retighten communication cable terminal connections at both the indoor and outdoor units and visually check the cable for obvious physical damage. However, if the wiring checks out and the fault persists, diagnosing or replacing a PCB typically requires a trained technician with the proper tools and access to replacement parts.
Is it safe to keep running my air conditioner with the *A error displayed?
The affected indoor unit will not operate while the *A error is active, so there is no immediate safety hazard from leaving the system powered on. However, the underlying cause, such as damaged wiring or a compromised PCB, should be addressed promptly to prevent potential further electrical damage to the system. Do not attempt to bypass the error or tamper with live electrical components without first disconnecting power.
Will resetting my Samsung air conditioner clear the *A error?
A power reset may temporarily clear the error display, but if the underlying communication problem remains, the *A code will return once the system attempts to re-establish communication between the units. A reset alone is not a fix. The root cause in the wiring or PCBs must be resolved for the error to clear permanently.
How much does it cost to repair the *A communication error on a Samsung air conditioner?
Repair costs vary depending on the cause. Replacing a communication cable typically costs between $75 and $200 including labor. Indoor or outdoor PCB replacement is more involved and can range from $200 to $600 or more depending on the specific board and labor rates in your area. A diagnostic service call to pinpoint the exact cause generally runs $75 to $150 before any parts are factored in.

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