Error Code P8
Mitsubishi Electric Air Conditioner
Severity:What Does This Error Mean?
Mitsubishi Electric Error P8 means the outdoor unit has detected an abnormal condition — commonly a fan fault, outdoor PCB issue, or refrigerant pressure problem. Turn the system off and contact a Mitsubishi Electric-authorised service agent.
Affected Models
- Mitsubishi Electric MSZ Series
- Mitsubishi Electric SRK Series
- Mitsubishi Electric MSZAP Series
Common Causes
- Outdoor unit fan motor fault
- Outdoor unit PCB detecting abnormal operating conditions
- Refrigerant pressure outside expected range
- Heat exchanger temperature sensor fault — outdoor unit
How to Fix It
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Turn off the system immediately.
Switch the AC off at the remote or wall controller and then at the isolator or circuit breaker. Running the system with a P8 fault can cause compressor damage.
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Inspect the outdoor unit visually.
Check that the outdoor unit fan is not obstructed by leaves, debris, or a plastic bag. Clear any blockage you can safely remove from outside the unit without touching internal components. Check that airflow around the outdoor unit is not restricted by fencing or vegetation.
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Check outdoor unit operating conditions.
Very high ambient temperatures (above 46°C / 115°F) can trigger P8 as the outdoor unit reaches thermal limits. If the error occurred during an extreme heat event, allow the unit to cool with the system off for 30 minutes and attempt to restart.
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Perform a power reset if the cause was heat.
If extreme heat was the likely cause, turn off at the isolator for 10 minutes, allow the outdoor unit to cool, then restore power. If P8 returns under normal outdoor temperatures, the fault is a hardware component failure.
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Book a Mitsubishi Electric authorised technician.
Provide the full error code including any sub-code to the technician. Common P8 repairs include outdoor fan motor replacement or outdoor PCB replacement.
When to Call a Professional
Error P8 diagnoses require a technician with refrigerant gauges and electrical test equipment. Turn the system off at the isolator and book a Mitsubishi Electric service agent.