0403 - Serial communication error

What does 0403 mean?

The outdoor unit's multi-controller board and power board are experiencing a communication issue, causing the air conditioning system to automatically stop operating. This code will appear on the remote controller or the outdoor unit LED.

• Communication trouble between the outdoor unit's multi-controller board and power board.

Click steps to track your progress.

1. 1

   Note the 0403 code displayed on your remote controller or the outdoor unit's LED.

2. 2

   Turn off the main power supply to the outdoor unit at the circuit breaker.

3. 3

   Wait at least 1 minute after LED1 and LED2 on the outdoor circuit board go out, then turn the main power supply back on.

4. 4

   If the error persists, contact a qualified service technician for further inspection.