Bosch Heat Pump Error Codes

Updated October 13, 2026 · by Aurora Star Tech Inc.

36 Bosch Heat Pump error codes and diagnostic codes, with causes and troubleshooting steps for each. Select a code, or find your model below.

Homeowner with a heat pump problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Bosch Heat Pump error codes list

Code	Meaning	Severity
AtL	Ambient temperature limited	Low
b2	Indoor T2 sensor fault	Medium
b3	Indoor refrigerant sensor hardware fault	Medium
b4	Indoor refrigerant sensor communication fault	Medium
b5	Indoor to outdoor communication fault	High
b7	R-454B refrigerant leak protection	Critical
b8	Refrigerant sensor past service life	Low
C3	T3 coil sensor not reading correctly in cooling	Medium
E7	T5 discharge sensor not reading correctly	Medium
E41	T3 temperature sensor fault	Medium
E42	T3L temperature sensor fault	Medium
E43	T4 temperature sensor fault	Medium
E44	T5 temperature sensor fault	Medium
E45	Th temperature sensor fault	Medium
E51	Input voltage out of range	High
E52	DC bus voltage out of range	High
E81	EEV coil fault	Medium
EA	Control and drive program mismatch	Medium
F1	High pressure switch protection	High
F2	System lockout (5 low-pressure trips in 100 minutes)	High
F4	Pressure transducer fault	Medium
F41	High pressure sensor fault	Medium
F42	Low pressure sensor fault	Medium
H01	Drive chip communication fault	High
J00-JCF	Compressor driver fault	High
n00-nCF	Outdoor fan motor driver fault	Medium
o37	Low refrigerant in heating	High
P0	Control board / compressor IPM overheating	High
P1	High pressure protection	High
P4	High compressor discharge temperature	High
P5	Condenser coil temperature protection (cooling)	High
P11	High pressure protection (transducer)	High
P21	Low pressure protection	High
P31	Input over-current protection	High
P32	Compressor over-current protection	High
PH	Low discharge superheat protection	High

Find codes by Bosch model

Bosch IDS Light

BOVA15-24 BOVA15-36 BOVA15-60

Bosch IDS Premium Connected

BOVA36-20 BOVA60-20

Homeowner help: AC Running But Not Cooling: What to Check · Heat Pump Not Heating or Blowing Cold Air

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Bosch Heat Pump error codes list

Find codes by Bosch model

Bosch IDS Light

Bosch IDS Premium Connected

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