Mitsubishi Air Conditioner Error P8

⚡ Quick Answer: The Mitsubishi Air Conditioner error code P8 signals a critical communication failure between the indoor and outdoor units, often caused by abnormal p... ✅ DIY Fixable

What Does Error P8 Mean?

The Mitsubishi Air Conditioner error code P8 signals a critical communication failure between the indoor and outdoor units, often caused by abnormal pipe temperature readings. This error typically leads to system shutdown, inefficient cooling or heating, and repeated operational interruptions. Common causes include thermistor or sensor issues, refrigerant circuit abnormalities, or faults within the outdoor unit itself. Immediate attention is advised to restore optimal performance.

Common Symptoms:

  • System stops operation and displays P8
  • Inefficient cooling/heating
  • Possible unexpected shutdowns

Possible Causes

  • Abnormal pipe temperature detected (thermistor/sensor issue) (high)
  • Refrigerant circuit abnormality (blockage, low refrigerant causing temperature deviation) (medium)
  • Outdoor unit related fault (sensor short/open, pressure/temperature protection) (medium)

How to Fix Error P8

DIY Fix Perform basic visual checks and restart

  1. Turn off the air conditioner using the remote or breaker
  2. Visually inspect outdoor unit area for debris or airflow obstruction
  3. Check for obvious loose wiring around accessible sensors
  4. Restore power and see if the error persists

Technician Only Diagnose and repair outdoor unit temperature sensor and refrigerant circuit

  1. Measure thermistor/pipe sensor resistance to verify within specification
  2. Confirm proper sensor mounting and wiring integrity
  3. Inspect refrigerant lines for blockages or leaks
  4. Check outdoor unit PC board for fault indications (LED codes)
  5. Replace faulty sensors or repair refrigerant circuit as needed

Parts needed: Pipe/line thermistor, Outdoor unit PC board (if faulty), Refrigerant (if leak detected)

🛑 When to Call a Pro:
  • If error persists after basic checks and simple restart
  • If you detect refrigerant leaks, abnormal noises, or repeated shutdowns
  • When any internal wiring or component measurement is needed

Technical Specifications

wattage N/A
component Control Board
resistance N/A
part_number Mitsubishi 938B100A
voltage_rating 230V AC

Common Questions

What does P8 error mean on Mitsubishi Air Conditioner?

The P8 error indicates a communication failure between the indoor and outdoor units, often due to abnormal pipe temperature.

Can I fix Mitsubishi Air Conditioner P8 error myself?

Yes, you can perform basic visual checks and restart the unit by inspecting the outdoor area for debris and ensuring wiring is secure.

How much does it cost to fix P8 error?

The estimated repair cost for the P8 error ranges from ¥10,000 to ¥70,000+, depending on the parts needed and refrigerant work.

When should I call a technician for P8?

Call a technician if the error persists after basic checks, if you notice refrigerant leaks, or if the unit makes abnormal noises.

Data last verified: 2026-07-01

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