E203 (Red ON, Green ON, Yellow Blink) — 1-minute communication timeout between Main and Inverter PCBs

What does E203 mean?

The outdoor unit's PCB LED displays E203 when communication between the main PCB and the inverter PCB times out for more than one minute. This suggests an internal communication issue within the outdoor unit.

• Loose or faulty electrical connections between PCBs
• Faulty main or inverter PCB
• Internal wiring damage

Click steps to track your progress.

1. 1

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

2. 2

   Wait for at least 30 seconds to allow the system to reset.

3. 3

   Restore power to the outdoor unit.

4. 4

   If the error continues, contact a qualified technician to inspect the internal electrical connections and PCBs within the outdoor unit.