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P3

P3 - System error (Transmitting/receiving signal)

Mitsubishi Heavy Industries · R410A Systems

What does P3 mean?

This indicates a system communication error between components, similar to an E0 error. It means signals are not being sent or received correctly, impairing system control.

Common Causes

  • Loose communication wiring.
  • Electromagnetic interference.
  • Faulty control board.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the air conditioning unit at the circuit breaker for 30 seconds.

  2. 2

    Restore power and restart the unit.

  3. 3

    Check for any obvious physical damage to wiring if safely accessible.

  4. 4

    If the error persists, a qualified service technician should inspect the control boards and wiring.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

E0E0 - Transmitting/receiving signal errorE12E12 - Auto address setting error or unit addressed at factory settingE14E14 (Flashes 3 times) - Master/slave system control wiring error
Source: Mitsubishi Heavy Industries R410A Systems
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