Toshiba SUPER MMK-AP0073H (IN) Service Manual page 86

Check code
[E28] / [d2]
(Current code / AI-NET)
Sub-code: Detected outdoor unit No.
An error occurred on the follower unit. Check the check code of follower unit on 7-segment display on I/F P .C.
board of follower unit, and then check according to Diagnose procedure for each check code.
(How to specify the follower outdoor unit in which error occurred)
If pushing SW04 for 1 second or more under condition that [E28] is displayed on 7-segment display of the
header unit, the fan of the outdoor which stopped due to occurrence of error starts rotating. When pushing
SW05 singly, the fan operation is cleared.
Check code
[E31] / [CF]
(Current code / AI-NET)
Sub-code:
01: IPDU1 error
03: IPDU1, 2 error
05: IPDU1, fan IPDU error
07: All IPDU error or communication line error between IPDU-I/F P .C. boards, or outdoor I/F P .C. board error
∗ If the fan IPDU is abnormal, be sure to check the voltage output on the fan power supply P.C. board.
Is communication connector between
IPDU and I/F P.C. board connected?
Is there no disconnection on communication
line between IPDU and I/F P.C. board?
Is there voltage deflection between
4 and 5 pin of CN600 on I/F P.C. board?
(Measurement with tester: DC0 to 5V, 5 pins GND)
Is there voltage deflection between
3 and 5 pin of CN600 on I/F P.C. board?
(Measurement with tester: DC0 to 5V, 5 pins GND)
Replace defective IPDU P.C. board.
Check code name
Follower outdoor unit error
Check code name
IPDU communication error
02: IPDU2 error
04: Fan IPDU error
06: IPDU2, fan IPDU error
YES
NO
YES
YES
Follower outdoor error
1. Connection error of communication line
between IPDU and I/F P.C. board
2. I/F P .C. board error
3. IPDU P.C. board error
4. External noise
NO
YES
NO
NO
All IPDU (No.1, No.2) and three fan
IPDU do not return communication.
86
Cause of operation
Cause of operation
Correct connection of connector.
Replace communication line.
I/F P.C. board error
I/F P.C. board error