Error 203 - Main and sub outdoor units communication error

What does 203 mean?

The main outdoor unit is unable to communicate with a sub outdoor unit within the system, interrupting coordinated operation.

• Communication wiring issue between the main and sub outdoor units
• Power supply problem to the sub outdoor unit
• Faulty outdoor unit control board

Click steps to track your progress.

1. 1

   Check the communication wiring connections between the main and sub outdoor units for any looseness or damage.

2. 2

   Ensure both the main and sub outdoor units are receiving stable power.

3. 3

   Power cycle both the main and sub outdoor units by turning off their main power for 30 seconds and then turning it back on.