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Error code reference

Samsung Air Conditioner Error Code U201

Communication error between outdoor unit main and sub MICOM or between outdoor units.

Samsung codesSamsung air conditioner codes
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What the U201 error code actually means

Your Samsung air conditioner's outdoor unit has detected that two of its internal control computers have stopped talking to each other, or that multiple outdoor units in a linked system have lost contact. This prevents the system from operating safely and it has shut down to avoid damage. A technician will need to check the electrical power and wiring connections inside the outdoor unit to find the cause.

Diagnostic procedure

The full U201 procedure

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1
First diagnostic step
Perform error reset (K3), check 12V and 5V power supply to the affected outdoor unit.
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Most common causes of U201

Ranked by how often they cause this code
  1. 1Missing or low DC supply voltage (12V or 5V)
  2. 2Damaged or disconnected communication wiring
  3. 3Corroded or loose inter-unit communication connectors
  4. 4Failed sub MICOM control board
  5. 5Failed main MICOM control board

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Questions people ask about U201

What does U201 mean on a Samsung air_conditioner?
U201 is a communication error code indicating that the main MICOM and sub MICOM inside the outdoor unit have lost contact, or that communication between linked outdoor units has failed. The system depends on this internal data exchange to coordinate compressor and fan operation. When it is interrupted, the unit shuts down and displays U201 to protect the system from running with incomplete control data.
Is it safe to keep running my air conditioner when U201 is displayed?
No. When U201 is active, the unit has already shut itself down because critical control communication has failed. Attempting to override or repeatedly restart the system without resolving the fault can stress components and potentially cause further damage to the MICOM boards or refrigerant circuit.
How much does it cost to repair a Samsung air conditioner U201 error?
Repair costs vary depending on the root cause. If the fix is simply reseating a loose connector or correcting a wiring issue, labor costs may be in the range of $75 to $200. If a MICOM control board requires replacement, parts alone can add $150 to $500 or more to the total, depending on the specific unit model and board availability.
Can I fix the U201 error myself?
The first step, performing an error reset (K3), can be attempted without specialized tools. However, verifying the 12V and 5V power supplies and inspecting internal wiring requires opening the outdoor unit and working near live components, which carries a serious electrical hazard. Most homeowners should have a certified technician handle diagnostics beyond the initial reset.
Will resetting the unit clear the U201 error?
A reset using the K3 procedure may clear the fault temporarily if the communication disruption was caused by a transient voltage event or momentary interference. If the underlying cause is a wiring fault, a failed board, or a missing power supply voltage, the error will return shortly after restart. A reset is a useful first step but not a permanent fix for hardware faults.

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