TCM MMCUT18AS2, Service Manual, Page: 41 / 127

41
Indoor / outdoor units communication error
Start: Power off , then Power on the
A/C by the Breaker. (reconnect the
power wire). Is it still displaying the
error code?
Yes
No
Change outdoor unit PCB assembly(include
wiring) totally
Check wiring on the outdoor and indoor
terminal follow the wiring diagram. Is all
connecting correctly?
Yes
No
Measure Vs, is it moving
alternately between positive value
and negative value? (Vs is the
voltage between S and L2). Refer
PIC 1
Turn on all indoor unit by remote
controller. Is all indoor unit display
Turn off the all indoor units. Is IPM
power LED or operating LED lamp
On? Refer PIC2
Yes
A :
Is all the wiring between
terminal and Indoor PCB
connect ok?
No
Yes
A
No
Reconnect the wiring
Is indoor units number correct? Check
on the outdoor check point . (2 for dual
zone, 3 for tri zone, 4 for qua zone).
Refer PIC 4.
Yes
No first time
Yes
Yes
Change the Indoor PCB
Power on by remote
controller, I Is it still
displaying the error code
after 3 minutes?
Trouble is solved
No second time
No
Yes
Reconnect the wiring
No
change IPM
No
Is the reactor connecting
well
？
No Reconnect the wiring
Change Outdoor Main PCB
Yes
No
Is main board
“ ”
lamp on? Refer PIC 3.