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Error code reference

Samsung Air Conditioner Error Code E606

CAUR to relay communication error.

Samsung codesSamsung air conditioner codes

CAUR to relay communication error.

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What E606 means on a Samsung air conditioner

The E606 error code on a Samsung air conditioner indicates a communication failure between the CAUR (Central Air Unit Relay) board and the relay component it is responsible for controlling. This communication link is critical for coordinating control signals between the main control board and the relay output stage, which manages power switching for compressor contactors, fan motors, and other high-load components. When the communication signal is interrupted, corrupted, or absent, the system logs E606 and typically halts normal operation to prevent uncontrolled component behavior.

The most common sources of this fault are wiring harness issues between the CAUR board and the relay module, including loose connectors, damaged insulation, or broken signal wires caused by vibration or improper installation. The CAUR board itself can also fail due to power surges, moisture ingress, or component-level failures on the PCB. In some cases, the relay module may have an internal fault that prevents it from acknowledging communication signals sent by the CAUR.

Diagnosing this error requires a systematic check of the communication wiring between the two components, including inspection of connector pins for corrosion or bent contacts. Technicians should also verify that the power supply to the CAUR board is stable and within specification, as undervoltage conditions can disrupt communication protocols. If wiring and power supply check out, component replacement of either the CAUR board or the relay module is typically the next step.

Source: manufacturer service documentation.

Common causes of E606

  1. 01

    Loose or disconnected wiring harness

    Wiring / connection

    The connector linking the CAUR board to the relay module may have worked loose due to vibration or improper installation. Inspect all connectors between the two components for secure seating and check pins for corrosion or bending.

  2. 02

    Damaged communication wiring

    Part replacement

    Signal wires between the CAUR board and relay can sustain damage from pinching, abrasion, or heat exposure. Visually trace the wiring path and use a multimeter to check for continuity breaks or shorts.

  3. 03

    Faulty CAUR board

    Part replacement

    The CAUR board may have failed internally due to a power surge, moisture damage, or component degradation. Look for visible burn marks, swollen capacitors, or signs of arcing on the PCB surface.

  4. 04

    Failed relay module

    Part replacement

    The relay module itself may have an internal fault preventing it from responding to signals from the CAUR board. If wiring and the CAUR board test correctly, the relay module is the next likely candidate for replacement.

  5. 05

    Unstable or low voltage supply to CAUR board

    Wiring / connection

    An undervoltage condition on the power supply line feeding the CAUR board can disrupt its communication output. Verify incoming voltage at the board is within the unit's specified operating range.

See the test procedure for each cause

Frequently asked questions about E606

What does E606 mean on a Samsung air conditioner?
E606 indicates a communication error between the CAUR board and the relay module inside the air conditioner. This means the two components cannot exchange control signals properly, which causes the unit to stop normal operation. It is an internal control system fault that requires inspection of the wiring and control boards.
Can I fix the E606 error myself?
Some causes, such as a loose wiring connector, can be addressed by a knowledgeable DIYer who is comfortable working inside the unit with the power fully disconnected. However, diagnosing and replacing the CAUR board or relay module involves working with internal electronics and should be handled by a qualified technician. Attempting repairs without proper knowledge risks further damage or electric shock.
Is it safe to run my Samsung air conditioner with the E606 error showing?
No, you should not continue operating the unit while E606 is active. The error indicates that a key communication link in the control system has failed, and running the system in this state could lead to uncontrolled operation of components or additional damage. Power off the unit and have it inspected before resuming use.
Will resetting the air conditioner clear the E606 error?
A power reset may temporarily clear the error display, but it will not resolve the underlying communication fault. If the wiring connection or board issue is still present, the E606 code will return once the unit attempts to resume normal operation. A proper diagnosis and repair of the root cause is necessary for a lasting fix.
How much does it cost to repair the E606 error on a Samsung air conditioner?
Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector, a service call fee of roughly 75 to 150 dollars may cover it. If the CAUR board or relay module needs replacement, parts and labor together can range from 200 to 600 dollars or more, depending on the unit model and local labor rates.

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