Bosch BMS500-AAU036-1AHCXC - IPM Board Communication Error (PC 40)

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Service Manual
Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units (01.2023)
8.6.3 IP M board and outdoor main control board communication error (PC 40)
Error Code PC 40
Malfunction decision conditions PCB main chip does not receive feedback from IPM module for 60 seconds.
Supposed causes
f Improper / Incorrect Wiring
f Outdoor PCB faulty
Table 33
Troubleshooting:
Figure 54
Communication malfunctionbetween
IPM board andoutdoor main board
Is thereatleast oneLED in
theIPM board light?
Checkthe signal wire between
theIPM moduleand themain
board, is it connected good?
Reconnect andretry.Is
errorstill display?
ReplaceIPM board,and
then checkwhether the
system canrun normally
Replacethe electric control
box
No
No
No
No
Yes
Troubleis solved
No
Yes
Replace outdoormain
board, and then check
whether the system can run
normally
No
Yes
Yes