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Bosch - Fault Codes

Article ID: 744
Last updated: 11 Mar, 2024

Bosch Heat Pump: M15, M18, M20

Re: Fault Codes / Status Codes


Fault Code Display
Fault Code Fault Description
C3 The coil sensor (T3) is seated fault in Cooling
E4 Temperature Sensor Fault (T3, T4, T3L, T5 or TF)
E5 High or Low Voltage Protection
E6 Outdoor Fan Motor Fault
E7 Compressor Discharge Sensor (T5) is seated fault
E9 EEPROM Fault
H0 Communication Fault in main control chip
H5 5 times (P2 Fault) in 100 minutes (Hard Lockout)
H8 Pressure Transducer Fault (PT)
P0 Control Board temperature protection (TF)
P1 High Pressure Switch protection (HPS)
P2 Low Pressure protection in heating or cooling (PT)
P3 Compressor Overcurrent protection
P4 High Compressor Discharge temperature protection (T5)
P5 Condenser Coil temperature protection in Cooling (T3)
P8 Outdoor Fan Motor hurricane/typhoon protection
PH Low discharge superheat protection
F1 High Pressure Switch (HPS) fault
L0-L9 IPM Fault
AtL Ambient Temperature limited

System Protection Status Codes
Display  Description
L Outdoor Coil (T3) limited condition
D Compressor Discharge (T5) limited condition
P Compressor ratio limited condition
F T5 limited condition
C Current limited condition
U Under low voltage limited condition
A Oil return mode
dF Defrost mode

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Article ID: 744
Last updated: 11 Mar, 2024
Revision: 8
Access: Public
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