Daikin GYEQ20AN, Руководство по обслуживанию

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Flow Charts for Troubleshooting SiAUY361411EA
165 Troubleshooting
41
Inter-CPU Communication Failure/
Software Mismatch/Abnormal ROM
Error
code
U2
Description
of the failure
Sub-code 0: Unable to communicate between I/O CPUs for 20 seconds.
Sub-code 2: Unable to communicate between ignition CPUs for 20 seconds.
Sub-code 3: Abnormal I/O CPU ROM
Sub-code 5: Abnormal ignition CPU ROM
Possible
causes
of the failure
CPU program write error; power supply circuit board failure; main circuit board failure; T phase missing
Flow chart
If checker display is
If sub-code 0 If sub-code 2 If sub-code 3 or 5
Software rewritten?
Is the power
supply circuit
board LED1 lit?
Is the power supply
circuit board fuse F4
operating normally?
Is the harness for main
circuit board CN10 and power
supply circuit board CN107
operating normally?
NO
NO
NO Replace main
circuit board
Replace the
fuse(s)
Replace the
circuit board
Harness
inspection
YES
Replace main
circuit board
YES
Rewrite software
again
YES
YES
Is the supply
voltage normal?
YES
NO
Power supply
voltage inspection
NO
Replace main
circuit board
025909-00EN02