A: Almost never. Unless the outdoor unit was struck by lightning and every component is fried, 9C is fixable by replacing the outdoor PCB alone, not the whole condenser unit. Get a second opinion if a technician suggests a full unit replacement for a 9C error.
If you use an external voltage stabilizer, it may be faulty or struggling to output a consistent current Outdoor PCB Fault: o general ac error code 9c
Before checking hardware, try a system reset to clear any temporary glitches. Turn off the AC via the remote A: Almost never
Disconnect the power at the main isolator switch or unplug the unit. Wait at least 5–10 minutes to allow the capacitors to discharge fully. Restore power and check if the code persists. Check Remote Wiring If you use an external voltage stabilizer, it