Samsung Air Conditioner Error Code OUTDOOR_YELLOW_GREEN_ON

The OUTDOOR_YELLOW_GREEN_ON error on a Samsung air conditioner signals a DC-link overvoltage condition in the outdoor unit. The DC-link is the internal DC bus that sits between the rectifier stage and the inverter drive stage of the outdoor unit's power electronics. When AC power is converted to DC for use by the inverter compressor drive, that DC voltage is stored and regulated across a bank of capacitors on the outdoor control board. If the voltage on this DC bus rises beyond the acceptable threshold, the system triggers this fault to protect the inverter components from damage.

Overvoltage on the DC-link can occur for several reasons. A sudden loss of load, such as the compressor stopping unexpectedly, can cause the voltage to spike upward if energy has nowhere to go. High incoming supply voltage from the utility can push the rectified DC level above safe limits. A failing or shorted braking circuit, or degraded DC-link capacitors that can no longer absorb voltage transients, are also common contributors. In some cases, a fault in the inverter module itself can cause improper voltage feedback, triggering a false overvoltage reading.

Diagnosis begins with the outdoor control board, which houses the DC-link capacitors, the IPM (Intelligent Power Module) or inverter drive circuitry, and the associated voltage sensing circuits. Technicians should measure the incoming supply voltage at the outdoor unit terminals to confirm it falls within rated limits, then inspect the control board for signs of burnt components, swollen capacitors, or damaged traces. If supply voltage is normal and the board shows physical damage, board replacement is the most likely repair path.