Bosch Air Conditioners Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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C1
C1 appears and the unit may not respond correctly to remote control commands.
Indoor Unit EEPROM Configuration Error
C5
C5 error and the unit may not start or may behave unpredictably.
Indoor PCB Jumper / Configuration Error
E0
Indoor unit displays E0 and the air conditioner does not respond to remote commands or buttons.
Indoor Unit EEPROM / Main PCB Communication Error
E1
Indoor unit shows E1 and the system will not start cooling or heating.
Indoor / Outdoor Communication Failure
E2
Indoor unit displays E2 and the unit stops cooling; indoor fan may continue to run.
Indoor Evaporator Coil Freeze Protection / Temperature Sensor Error
E3
E3 appears and the outdoor unit stops; compressor may not start or stops shortly after starting.
Outdoor Low-Pressure Protection / Refrigerant System Undercharge
E4
E4 is displayed and the unit stops cooling or heating; may restart after some time.
High-Pressure Protection / Condenser Overheat
E5
E5 appears and the compressor does not start or stops shortly after starting.
Overcurrent Protection / Compressor Overload
E6
E6 is displayed and the indoor unit may run the fan but no cooling or heating occurs.
Indoor / Outdoor Communication Timeout
E7
E7 error and the indoor louver does not move correctly or makes clicking noises.
Indoor Louver Motor / Stepper Motor Fault
E8
E8 appears and the unit may shut down unexpectedly, often during high load.
Indoor Fan Motor Overload / Feedback Error
E9
E9 is displayed and the unit may stop with water dripping or internal beeping.
Full Condensate Drain Pan / Drain Pump Fault (if equipped)
F0
F0 error and the unit may not start or may shut down shortly after starting.
Indoor Ambient Temperature Sensor Fault
F1
F1 is displayed and the unit may operate erratically, not reaching set temperature.
Indoor Evaporator Coil Temperature Sensor Fault
F2
F2 error and the outdoor unit may not run or may shut down frequently.
Outdoor Condenser Coil Temperature Sensor Fault
F3
F3 appears and the unit may not defrost properly in heating mode or may shut down.
Outdoor Discharge Pipe Temperature Sensor Fault
F4
F4 error and the compressor may not start or may shut down quickly.
Outdoor Ambient Temperature Sensor Fault
F5
F5 is displayed and the unit may not operate in certain modes or may shut down.
Condenser Overheat / Sensor Correlation Fault
H1
H1 is shown on the display and the unit stops blowing warm air in heating mode; outdoor unit may frost up.
Defrost Mode Active / Defrost Protection
H3
H3 error and the outdoor unit stops; compressor may be very hot.
Compressor Overheat Protection
H5
H5 is displayed and the unit will not run; sometimes accompanied by E5 or other inverter-related codes.
Inverter Module Protection / IPM Overcurrent
P0
P0 appears and the unit may not start or may run at reduced capacity.
Inverter Module Self-Protection / DC Bus Voltage Abnormal
P1
P1 error and the unit may stop or limit operation, especially in heating mode.
Low Refrigerant Charge / System Protection
P2
P2 is displayed and the unit may stop cooling or heating intermittently.
High Discharge Temperature Protection
P4
P4 error and the indoor unit may shut down or run only the fan.
Indoor Coil Overheat / Protection
Symptom
Air conditioner does not start at all; no lights on the indoor unit.
No Power to Indoor Unit
Symptom
Air conditioner runs but does not cool the room effectively (no error code displayed).
Insufficient Cooling Capacity / Performance Degradation
Symptom
Excessive vibration and noise transmitted through the wall or floor when the outdoor unit runs.
Outdoor Unit Vibration / Mounting Issue
Symptom
Indoor unit blows air but there is a noticeable chemical or burning smell.
Electrical Overheating or Contaminant Odor
Symptom
Indoor unit display or LEDs flicker or are very dim, but the unit still runs.
Indoor Display Power / Low Voltage Issue
Symptom
Indoor unit has power but will not respond to remote control commands.
Remote Control / IR Receiver Failure
Symptom
Loud humming or grinding noise from the outdoor unit.
Outdoor Mechanical Noise / Fan or Compressor Issue
Symptom
Loud rattling or buzzing noise from the indoor unit during operation.
Indoor Mechanical Vibration / Loose Components
Symptom
Strong musty or moldy smell when the air conditioner starts.
Biological Growth on Evaporator Coil and Drain Pan
Symptom
Unit emits clicking sounds repeatedly but does not start cooling or heating.
Relay / Contactor Chatter or Start Failure
Symptom
Unit frequently turns on and off (short cycling) without maintaining temperature.
Short Cycling / Control or Sizing Issue
Symptom
Unit in heating mode blows only cool or lukewarm air; outdoor unit may frost heavily.
Poor Heating Performance / Heat Pump Issue
Symptom
Unit runs but ice forms on the indoor coil or suction line.
Evaporator Icing / Low Suction Pressure
Symptom
Unit runs in cooling but the outdoor fan does not start; indoor unit may show no error.
Outdoor Fan Motor Failure Without Code
Symptom
Water leaking from the front of the indoor unit onto the wall or floor.
Condensate Drainage Failure
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| C1 |
C1 appears and the unit may not respond correctly to remote control commands.
|
Indoor Unit EEPROM Configuration Error | View Details |
| C5 |
C5 error and the unit may not start or may behave unpredictably.
|
Indoor PCB Jumper / Configuration Error | View Details |
| E0 |
Indoor unit displays E0 and the air conditioner does not respond to remote commands or buttons.
|
Indoor Unit EEPROM / Main PCB Communication Error | View Details |
| E1 |
Indoor unit shows E1 and the system will not start cooling or heating.
|
Indoor / Outdoor Communication Failure | View Details |
| E2 |
Indoor unit displays E2 and the unit stops cooling; indoor fan may continue to run.
|
Indoor Evaporator Coil Freeze Protection / Temperature Sensor Error | View Details |
| E3 |
E3 appears and the outdoor unit stops; compressor may not start or stops shortly after starting.
|
Outdoor Low-Pressure Protection / Refrigerant System Undercharge | View Details |
| E4 |
E4 is displayed and the unit stops cooling or heating; may restart after some time.
|
High-Pressure Protection / Condenser Overheat | View Details |
| E5 |
E5 appears and the compressor does not start or stops shortly after starting.
|
Overcurrent Protection / Compressor Overload | View Details |
| E6 |
E6 is displayed and the indoor unit may run the fan but no cooling or heating occurs.
|
Indoor / Outdoor Communication Timeout | View Details |
| E7 |
E7 error and the indoor louver does not move correctly or makes clicking noises.
|
Indoor Louver Motor / Stepper Motor Fault | View Details |
| E8 |
E8 appears and the unit may shut down unexpectedly, often during high load.
|
Indoor Fan Motor Overload / Feedback Error | View Details |
| E9 |
E9 is displayed and the unit may stop with water dripping or internal beeping.
|
Full Condensate Drain Pan / Drain Pump Fault (if equipped) | View Details |
| F0 |
F0 error and the unit may not start or may shut down shortly after starting.
|
Indoor Ambient Temperature Sensor Fault | View Details |
| F1 |
F1 is displayed and the unit may operate erratically, not reaching set temperature.
|
Indoor Evaporator Coil Temperature Sensor Fault | View Details |
| F2 |
F2 error and the outdoor unit may not run or may shut down frequently.
|
Outdoor Condenser Coil Temperature Sensor Fault | View Details |
| F3 |
F3 appears and the unit may not defrost properly in heating mode or may shut down.
|
Outdoor Discharge Pipe Temperature Sensor Fault | View Details |
| F4 |
F4 error and the compressor may not start or may shut down quickly.
|
Outdoor Ambient Temperature Sensor Fault | View Details |
| F5 |
F5 is displayed and the unit may not operate in certain modes or may shut down.
|
Condenser Overheat / Sensor Correlation Fault | View Details |
| H1 |
H1 is shown on the display and the unit stops blowing warm air in heating mode; outdoor unit may frost up.
|
Defrost Mode Active / Defrost Protection | View Details |
| H3 |
H3 error and the outdoor unit stops; compressor may be very hot.
|
Compressor Overheat Protection | View Details |
| H5 |
H5 is displayed and the unit will not run; sometimes accompanied by E5 or other inverter-related codes.
|
Inverter Module Protection / IPM Overcurrent | View Details |
| P0 |
P0 appears and the unit may not start or may run at reduced capacity.
|
Inverter Module Self-Protection / DC Bus Voltage Abnormal | View Details |
| P1 |
P1 error and the unit may stop or limit operation, especially in heating mode.
|
Low Refrigerant Charge / System Protection | View Details |
| P2 |
P2 is displayed and the unit may stop cooling or heating intermittently.
|
High Discharge Temperature Protection | View Details |
| P4 |
P4 error and the indoor unit may shut down or run only the fan.
|
Indoor Coil Overheat / Protection | View Details |
| – |
Air conditioner does not start at all; no lights on the indoor unit.
|
No Power to Indoor Unit | View Details |
| – |
Air conditioner runs but does not cool the room effectively (no error code displayed).
|
Insufficient Cooling Capacity / Performance Degradation | View Details |
| – |
Excessive vibration and noise transmitted through the wall or floor when the outdoor unit runs.
|
Outdoor Unit Vibration / Mounting Issue | View Details |
| – |
Indoor unit blows air but there is a noticeable chemical or burning smell.
|
Electrical Overheating or Contaminant Odor | View Details |
| – |
Indoor unit display or LEDs flicker or are very dim, but the unit still runs.
|
Indoor Display Power / Low Voltage Issue | View Details |
| – |
Indoor unit has power but will not respond to remote control commands.
|
Remote Control / IR Receiver Failure | View Details |
| – |
Loud humming or grinding noise from the outdoor unit.
|
Outdoor Mechanical Noise / Fan or Compressor Issue | View Details |
| – |
Loud rattling or buzzing noise from the indoor unit during operation.
|
Indoor Mechanical Vibration / Loose Components | View Details |
| – |
Strong musty or moldy smell when the air conditioner starts.
|
Biological Growth on Evaporator Coil and Drain Pan | View Details |
| – |
Unit emits clicking sounds repeatedly but does not start cooling or heating.
|
Relay / Contactor Chatter or Start Failure | View Details |
| – |
Unit frequently turns on and off (short cycling) without maintaining temperature.
|
Short Cycling / Control or Sizing Issue | View Details |
| – |
Unit in heating mode blows only cool or lukewarm air; outdoor unit may frost heavily.
|
Poor Heating Performance / Heat Pump Issue | View Details |
| – |
Unit runs but ice forms on the indoor coil or suction line.
|
Evaporator Icing / Low Suction Pressure | View Details |
| – |
Unit runs in cooling but the outdoor fan does not start; indoor unit may show no error.
|
Outdoor Fan Motor Failure Without Code | View Details |
| – |
Water leaking from the front of the indoor unit onto the wall or floor.
|
Condensate Drainage Failure | View Details |
No matching codes found
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