P4
Bosch
Indoor Coil Overheat / Protection
P4 error and the indoor unit may shut down or run only the fan.
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Possible Causes
Blocked indoor airflow, Dirty filters, Indoor fan motor failure, Faulty indoor coil temperature sensor
How to Fix / Troubleshooting
Safety first: Disconnect power before cleaning.
Steps:
- Clean filters: Remove and wash Bosch filters thoroughly.
- Inspect coil: If accessible, vacuum dust from the evaporator fins.
- Check fan: Ensure the indoor fan runs at all speeds and is not obstructed.
If P4 persists: The coil sensor or indoor PCB may be faulty and should be checked by a technician.
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Repair Difficulty
Easy
2/5
Required Part
Indoor Fan Motor
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