MXZ-SM36NAMHZ Service Manual

58
OCH789
Check code
0403
(Ed)
Serial communication error
Abnormal points and detection methods Causes and checkpoints
If serial communication between the outdoor multi controller circuit board
and outdoor power circuit board is defective.
Wire breakage or contact failure of connector CN2 or
CN4
Malfunction of communication circuit to power circuit
board on outdoor multi controller circuit board
Malfunction of communication circuit on outdoor
power circuit board
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
No
Yes
No
Yes
Are they connected normally?
Are they connected normally?
Check the connection of the communication
line (CN2 and CN4) between the outdoor
controller board and power board.
Connect the wiring properly.
Replace them in the case of breakage.
Connect the CN2 and CN4 properly.
Replace them in the case of breakage.
The communication circuit of either the
outdoor controller board or power board is
defective.
If unable to identify the defective circuit;
Replace the outdoor controller board if it
does not recover,
Replace the outdoor power board.
Check the wiring.
8-1-3. SELF-DIAGNOSIS ACTION BY FLOWCHART