Bosch IDS 2.0 - P4 Troubleshooting

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Bosch IDS 2.0 Service Manual
07.2021 | Bosch Thermotechnology Corp.
Data subject to change
12.3.13 P4 Troubleshooting
LED display output: P4
Description: High compressor discharge temperature (T5) protection
Possible causes:
 Poor heat exchange on coil (cooling mode – outdoor coil, heating mode – indoor coil)
 Fan motor failure (cooling mode – outdoor fan, heating mode – indoor fan)
 Service valves not open
 TXV/EEV/filter drier blocked
 Over charged
Table 41
Procedure:
Figure 28
Are you running in
force mode?
Ye s
Ye s
Is there still a fault
code?
Is ambient
temperature >
120F?
No
Ye s
Quit force mode
No
Ye s
If the system is
overcharged
Ye s
Follow IOM to adjust
refrigerant
No
Did T5 sensor fail? 
Ye s
Replace T5
No
Restart system
Check for abnormal
pressure 
No
No service required
1) See Section 13.1
2) See Section 13.4