All Hitachi error codes
This page gathers Hitachi error codes sorted by type of failure: what each code means, its likely causes, and what you can safely check before calling a professional.
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The Hitachi codes on this page, grouped by type of failure.
General Fault — Hitachi
These codes don’t point to a specific part: the unit is indicating that an internal safety feature has been triggered.
Code 31Critical severityair-to-air
Capacity setting error (module pairing)
Possible causes
- Incompatible power modules
- Board replaced without configuration
- Capacity jumper incorrectly positioned
What you can check
- Technician visit for reconfiguration
Affected models: RAS-DJ, RAS-AJ, RAC-DJ
This issue requires a qualified technician. Do not open the unit.
Code 38Critical severityair-to-air
Fault in the outdoor protection detection circuit
Possible causes
- Faulty protection board
- Wiring for a cut-off pressure switch
- Protection sensor failed
What you can check
- Cut the power for 30 minutes, then restart
Affected models: RAS-DJ, RAS-AJ, RAC-DJ
This issue requires a qualified technician. Do not open the unit.
Fan — Hitachi
The fan releases or captures heat. If it’s blocked or faulty, pressure rises and triggers a shutdown.
Code 08Medium severityair-to-air
Indoor fan motor fault
Possible causes
- Faulty fan motor
- Blocked fan
- Faulty motor capacitor
What you can check
- Check for obstructions
- Turn off power for 10 min, then restart
Models concerned: RAK-DJ, RAK-DJP, RAS-DJ
This issue requires a qualified technician. Do not open the unit.
Code 10Medium severityair-to-air
Outdoor fan motor fault
Possible causes
- Faulty outdoor fan motor
- Foreign object
- Capacitor failure
What you can check
- Check for obstructions
- Turn off power for 10 minutes, then restart
Models affected: RAS-DJ, RAS-AJ, RAC-DJ
This issue requires a qualified technician. Do not open the unit.
Compressor — Hitachi
The compressor is the most critical and expensive part. These codes protect the unit by shutting it down before damage occurs: never force repeated restarts.
Code 11Medium severityAir-to-air
Return air sensor (inlet) fault on indoor unit
Possible causes
- Thermistor cut off or short-circuited
- Connector unplugged
- Faulty indoor control board
Models affected: RAS-DJ, RAS-AJ, RAC-DJ
This issue requires a qualified technician. Do not open the unit.
Temperature sensor — Hitachi
These codes indicate a sensor that’s no longer returning a consistent value. The fault almost always comes from the sensor itself or its connector, rarely from the unit.
Code 04Medium severityair-to-air
Outdoor coil thermistor fault
Possible causes
- Faulty outdoor coil thermistor
- Faulty wiring
What you can check
- Turn off the power for 30 minutes, then restart
Models affected: RAS-DJ, RAS-AJ, RAC-DJ
This issue requires a qualified technician. Do not open the unit.
Reversing valve — Hitachi
Code 05Critical severityair-to-air
Power supply fault / phase reversal
Possible causes
- Missing phase
- Phase reversal (three-phase)
- Voltage out of range
- Blown fuse
What you can check
- Check the electrical panel and fuses
- Have an electrician check the phase order
Models affected: RAS-DJ, RAS-AJ, RAC-DJ, RAK-DJ
This issue requires a qualified technician. Do not open the unit.
All Hitachi codes published on the site
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Technical information provided for reference only, based on manufacturer documentation and field feedback. It does not replace a diagnosis by a qualified professional. Found an error on this page? Report it.