Samsung Air Conditioner Error Code U202

U202 indicates a communication error between the main MICOM and sub MICOM inside the outdoor unit, or between two outdoor units in a linked system. The control boards have lost their data connection, causing the system to stop operating. This is a hardware or wiring-level fault that requires diagnosis at the outdoor unit.

Some steps, such as performing a reset or visually inspecting connector harnesses for obvious looseness, are within reach for a knowledgeable DIYer. However, measuring the 12V and 5V supply rails with a multimeter and safely accessing the outdoor unit control boards requires comfort working with electrical components. If you are not experienced with low-voltage electronics diagnosis, a certified HVAC technician is the safer choice.

Repair costs depend heavily on the root cause. If the fix is simply reseating a loose connector, the cost is mainly a diagnostic service call, typically in the range of $75 to $150. Replacing a damaged wiring harness may add $50 to $200 in parts. A MICOM board replacement is the most expensive scenario, with parts and labor commonly ranging from $250 to $600 or more depending on the unit model and local labor rates.

An error reset using the K3 procedure is the recommended first step and may clear the code if it was triggered by a temporary power fluctuation. However, if the underlying cause is a wiring fault, failed power supply, or defective MICOM board, the error will return after the reset. A reset alone is not a fix, it is a starting point for diagnosis.

The system typically shuts down when U202 is active, preventing normal operation. Attempting to force the system to run while the MICOM communication link is broken risks uncoordinated control of the compressor and other components. Leave the unit off until the fault is diagnosed and resolved.