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Error code reference

Samsung Air Conditioner Error Code E202

Communication error between indoor and outdoor units (communication error on all indoor units, outdoor unit…

Samsung codesSamsung air conditioner codes

Communication error between indoor and outdoor units (communication error on all indoor units, outdoor unit communication cable error).

First step from the service manual

Press reset key (K3) of outdoor PCB and check display module.

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

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What E202 means on a Samsung air conditioner

The E202 error code on a Samsung air conditioner indicates a communication failure between the indoor and outdoor units. Specifically, this fault means the outdoor unit is unable to establish or maintain a valid communication signal with all connected indoor units simultaneously. The communication link between these two sections of the system relies on a dedicated signal cable, typically a two or three-wire connection that carries serial data used to coordinate compressor operation, fan speed, temperature feedback, and mode control. When this link is interrupted or degraded across all indoor units at once, the outdoor unit detects a total communication loss and triggers the E202 fault.

The most common hardware involved is the communication cable running between the indoor and outdoor PCBs, along with the outdoor PCB itself. A fault described as affecting all indoor units simultaneously points strongly toward a problem on the outdoor unit side of the circuit, since an issue localized to one indoor unit would typically produce a different fault code. This pattern suggests either the outdoor PCB's communication circuit has failed, the wiring between the units is damaged or disconnected, or there is a power supply issue affecting the communication logic on the outdoor board.

The first recommended diagnostic step is to press the reset key, labeled K3, on the outdoor PCB and then observe the display module for any change in fault status. This hard reset clears stored fault flags and forces the outdoor unit to attempt re-establishing communication from scratch. If the error clears and communication resumes, the fault may have been caused by a transient electrical event such as a power surge or voltage fluctuation. If E202 returns immediately after the reset, a physical wiring problem or a failed outdoor PCB is the more likely culprit and will require hands-on inspection.

Source: manufacturer service documentation.

Common causes of E202

  1. 01

    Damaged or disconnected communication cable

    Part replacement

    The signal wire running between the indoor and outdoor units may be broken, pinched, or pulled loose from its terminal. Inspect the full length of the communication cable and check that all connectors are firmly seated at both the indoor and outdoor PCBs.

  2. 02

    Failed outdoor unit PCB

    Part replacement

    If the communication circuit on the outdoor PCB has failed, the unit cannot send or receive signals to any indoor unit, which matches the E202 pattern of all indoor units losing communication at once. The board will need to be tested and likely replaced.

  3. 03

    Transient power surge or voltage fluctuation

    Wiring / connection

    A sudden spike or dip in supply voltage can temporarily corrupt the communication protocol and cause the outdoor unit to log a fault. Pressing the K3 reset button on the outdoor PCB is the first step to rule this out, as the error may clear without further repair.

  4. 04

    Incorrect communication wiring polarity or loose terminals

    Wiring / connection

    Communication cables that are reversed at the terminal block or that have a loose screw connection will prevent a valid signal from being established. Check polarity and terminal tightness at both ends of the communication wiring run.

  5. 05

    Failed indoor unit PCB affecting communication line

    Part replacement

    In some cases, a shorted communication circuit on an indoor PCB can drag down the entire communication bus, causing all units to appear offline from the outdoor unit's perspective. If wiring and the outdoor board check out, each indoor PCB should be inspected in turn.

See the test procedure for each cause

Frequently asked questions about E202

What does E202 mean on a Samsung air conditioner?
E202 indicates a communication error between the outdoor unit and all connected indoor units, meaning the outdoor PCB has lost its data link with the indoor side of the system. This is flagged when communication fails across every indoor unit simultaneously, which points to the outdoor unit's communication circuit or the wiring connecting the two sections. The system stops normal operation to protect components until the link is restored.
Can I fix E202 myself or do I need a technician?
The first step, pressing the K3 reset button on the outdoor PCB and checking the display, is something a knowledgeable homeowner can attempt safely with the unit powered. If the error clears after the reset, monitor the system to see if it returns. However, if the error persists, diagnosing a wiring fault or a failed PCB requires working inside electrical enclosures with potentially dangerous voltages, so a qualified technician should handle further troubleshooting.
Will resetting the unit clear the E202 error?
Pressing the K3 reset key on the outdoor PCB forces the unit to reattempt communication from the beginning, and the error will clear if the original cause was a temporary electrical disturbance. If the underlying problem is a physical wiring fault or a damaged PCB, the E202 code will return shortly after the reset because the root cause has not been addressed. A reset is a useful first diagnostic step, not a guaranteed fix.
Is it safe to run my Samsung air conditioner when E202 is displayed?
No, the system will not operate normally during an E202 fault because the outdoor unit cannot coordinate with the indoor units. Attempting to force operation without a valid communication link can cause incorrect behavior and potential component damage. The system should remain off until the communication fault is diagnosed and resolved.
How much does it cost to repair an E202 error on a Samsung air conditioner?
Repair costs depend on the root cause. If the fix involves reseating a loose communication wire or clearing a transient fault with a reset, labor costs may be minimal, typically in the range of $75 to $150 for a service call. Replacing a communication cable may add $50 to $150 in parts and labor. If the outdoor PCB has failed, board replacement can cost anywhere from $200 to $600 or more depending on the unit model and labor rates in your area.

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