Bosch BMS500-AAU009-0AHXXA Service Manual page 42

4 2 | Bosch Climate 5000 AA Series Split Type Ductless Air Conditioner / Heat Pump
8.3.11 Inverter compressor drive error diagnosis and solution(P4)
Error Code
Malfunction decision conditions
Supposed causes
Table 26
Troubleshooting:
Check the wiring between main PCB
and compressor
Check the outdoor fan and the
Check the compressor resistance
Replace the outdoor main PCB
Figure 39
Data subject to change
P4
An abnormal inverter compressor drive is detected by a special detection circuit, including
communication signal detection, voltage detection, compressor rotation speed signal detection and so
on.
Wiring mistake
IPM malfunction
Outdoor fan assembly faulty
Compressor malfunction
Outdoor PCB faulty
No
Check the IPM
Yes
outdoor unit ventilation
Yes
values
Yes
Correct the connection or replace
Yes
the wires and connectors.
Replace the IPM board or replace
No
the main PCB
Please refer to the solution of 【Fan
No
Speed Has Been Out Of Control】
malfunction
No Replace the compressor.
Service Manual
02.2018 | Bosch Thermotechnology Corp.