Error Code: PC 40 – Communication Error Between Outdoor Main Chip and Compressor Driven Chip

Error Code: PC 40 – Communication Error Between Outdoor Main Chip and Compressor Driven Chip

What this means:
The main control board in the outdoor unit cannot detect or communicate with the IPM (Intelligent Power Module)board. This failure interrupts the system's ability to control the compressor, triggering a communication faultTS26.

Try this first (quick reset):

1. Power off the unit completely.

2. Wait 2 full minutes.

3. Turn it back on and observe the error status.

• If the error clears — communication may have recovered.

• If it returns — proceed with diagnostics.

Next steps (for technicians):

1. Check for LED indicator on the IPM board:

   • If no LED is lit → proceed to inspect the signal path.

2. Inspect the signal wire between IPM board and outdoor main board:

   • If not connected or damaged → reconnect or replace the wire.

3. Reconnect and retry:

   • If the error persists → replace the IPM board.

4. If error continues after IPM board replacement:

   • Replace the electric control box.

5. If still unresolved:

   • Replace the outdoor main control board.

What you might need:

• Signal connection wires

• IPM module board

• Outdoor main PCB

• Electric control box

Helpful tip:
LED indicators on the IPM board can quickly confirm whether power and communication are active. Start with this visual check before replacing components.

Click here to view the detailed guide.TS26