Carrier 38QUS012D8S Service Manual page 137

2.4.4.16. J4 Malfunction
J4 displayed
J4 displayed
Communication error between outdoor main
Communication error between outdoor main
chip and compressor driven chip
chip and compressor driven chip
Is there at least one LED in the
Is there at least one LED in the
compressor driven chip light?
compressor driven chip light?
No
Check the signal wire between the
Check the signal wire between the
Compressor driven chip and the
Compressor driven chip and the
main board, is it connected
main board, is it connected
properly?
properly?
No
Reconnect and retry. Is the
Reconnect and retry. Is the
error still displayed?
error still displayed?
No
Replace Compressor driven
Replace Compressor driven
Chip. Is the system running
Chip. Is the system running
normally?
normally?
No
Replace outdoor main board.
Replace outdoor main board.
Is the system running
Is the system running
normally?
normally?
No
Replace the electric control box
Replace the electric control box
Electrical Control System
Yes
Yes
No
Yes
Yes
Problem is resolved
Problem is resolved
Troubleshooting
135