If the basic checks fail, an O General authorized service technician will perform advanced diagnostics:
, which requires a professional technician to diagnose and replace parts. Are you using a wired wall remote handheld wireless remote for your unit? How to Reboot and Reset Your Air Conditioner o general ac error code 9c
: If you recently replaced a PCB (Printed Circuit Board), the 9C code often signals that the new board is not compatible with your specific model version. If the basic checks fail, an O General
: Turn off the AC using the main power switch or circuit breaker. Leave it off for at least 10 minutes to clear the system's memory before turning it back on. : Turn off the AC using the main
Crucially, the technician will perform a . Disconnecting the compressor and measuring ohms between its three pins should reveal low, equal values (e.g., 1-3 ohms). An open circuit (infinite resistance) or a short to ground (continuity between a pin and the copper refrigerant line) indicates a failed compressor. Finally, a mechanical lock test involves using a multimeter with a capacitance or, more reliably, a specialized tool to listen for the compressor’s internal sound during startup—a humming with no rotation points to a mechanical lock.
While less common than a motor failure, the main control board (PCB) itself can be the culprit. If the capacitors on the board fail or the relays get stuck, the board won't send the correct voltage to the fan motor, resulting in an error.