17.4.17. J4 Malfunction   
Communication error between outdoor main 
chip and compressor driven chip
Communication error between outdoor main 
chip and compressor driven chip
Is there at least one LED in the 
compressor driven chip light?
Is there at least one LED in the 
compressor driven chip light?
Check the signal wire between the 
Compressor driven chip and the 
main board, is it connected 
properly?
Check the signal wire between the 
Compressor driven chip and the 
main board, is it connected 
properly?
Reconnect and retry. Is the 
error still displayed?
Reconnect and retry. Is the 
error still displayed?
Replace Compressor driven 
Chip. Is the system running 
normally?
Replace Compressor driven 
Chip. Is the system running 
normally?
Replace the electric control box
Replace the electric control box
No
No
No
No
Yes
Problem is resolved
Problem is resolved
No
Yes
Replace outdoor main board. 
Is the system running 
normally?
Replace outdoor main board. 
Is the system running 
normally?
No
Yes
Yes
J4 displayed
J4 displayed