If your Fujitsu air conditioning unit is displaying the A1 error code, it indicates a malfunction of the indoor unit’s PCB (Printed Circuit Board). This board controls key functions of the system, and a failure could result in total system shutdown.
Loose or damaged wiring between the PCB and other components may cause the failure.
Voltage instability can damage the PCB, leading to this error.
Over time, the PCB can fail due to aging components or electrical stress.
Turn the unit off at the power switch, wait 5–10 minutes, and then turn it back on.
If you’re able, visually inspect the PCB for burnt components or other visible signs of damage.
Check that the unit is receiving a consistent power supply and that no electrical surges have occurred.
If the problem persists, the PCB may need to be replaced by a professional.