HVACopediaBosch heat pump error codes
36 codes with causes and test steps.
| Code | Meaning | Severity |
|---|---|---|
| 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 |
| 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 |
| AtL | Ambient temperature limited | Low |
| EA | Control and drive program mismatch | Medium |
| PH | Low discharge superheat protection | High |
Models covered
BOVA-36HDN1-M20GBOVA-60HDN1-M20GBOVA15-24BOVA15-36BOVA15-60BOVA36-20BOVA60-20
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.