Samsung Air Conditioner Error Code U200

U200 indicates a communication error between the outdoor unit's main MICOM and sub MICOM controllers, or between multiple linked outdoor units. The two internal computers that coordinate outdoor unit operation have lost contact with each other. The system shuts down to prevent unsafe operation until the communication link is restored. A technician should check the 12V and 5V power supply to the outdoor control board as the first diagnostic step.

The system will typically shut down automatically when U200 is active, which is a protective response. Attempting to force the unit to operate while the MICOM communication link is broken could result in uncoordinated compressor and fan behavior. The unit should remain off until a technician has diagnosed and resolved the fault.

Repair cost depends on the root cause. If the fault is a loose connector or corroded wiring, labor charges for diagnosis and repair might range from $75 to $200. If a control board replacement is needed, parts alone can range from $150 to $500 or more depending on the specific outdoor unit model, with additional labor on top. Getting a diagnostic visit from a certified technician is the best way to get an accurate estimate for your specific situation.

A reset using the K3 error reset procedure can clear U200 if it was caused by a temporary power fluctuation or communication glitch. If the underlying cause is a hardware fault such as a failed power supply, damaged wiring, or a defective control board, the error will return shortly after the reset. Always check the 12V and 5V supply voltages after performing the reset to determine whether a hardware problem exists.

Start by performing the K3 error reset and observing whether the code returns. If it does, a qualified technician should measure the 12V and 5V DC power supply outputs at the outdoor unit control board. If those voltages are correct, the communication wiring harness between the main and sub MICOM boards should be inspected for damage or loose connectors. In multi-unit systems, the inter-unit communication wiring terminals should also be verified.