Midea M2OC-18HFN1-M Service Manual page 62

9.4.2.3 E3(Communication malfunction between IPM board and outdoor main board) error diagnosis
and .
Error Code
Malfunction decision
conditions
Supposed causes
Trouble shooting:
E3
PCB main chip does not receive feedback from IPM module
during 60 seconds.
● Wiring mistake
● PCB faulty
Communication malfunction between
IPM board and outdoor main board
Is there at least one LED in
the IPM board light?
No
Check the signal wire between
the IPM module and the main
board, is it connected good?
No
Reconnect and retry. Is
error still display?
No
Replace IPM board, and
then check whether the
system can run normally
No
Replace outdoor main
board, and then check
whether the system can run
normally
No
Replace the electric control
box
Yes
Yes
No
Yes
Yes
Trouble is solved