CodeRegistry
Brands
  1. Home
  2. Mitsubishi Heavy Industries
  3. Air Conditioners
  4. E43 / Outdoor Red LED 1 flash
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

E43 / Outdoor Red LED 1 flash

Error E43 / Outdoor Red LED Flashes Once — Max indoor units exceeded

Mitsubishi Heavy Industries · Air Conditioners

What does E43 / Outdoor Red LED 1 flash mean?

Error E43, indicated by one flash of the outdoor unit's red LED, means the maximum allowed number of indoor units connected to a single outdoor unit has been exceeded.

Common Causes

  • The maximum number of indoor units connected to one outdoor unit has been exceeded

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Consult your system's installation manual to determine the maximum number of indoor units supported by your outdoor unit.

  2. 2

    If the number of connected units is too high, the system configuration must be revised.

  3. 3

    This typically requires adjustment or disconnection of some indoor units, or adding another outdoor unit.

  4. 4

    Contact your installer or a professional technician to reconfigure the system.

Browse all codes in this manual (110)
Verified technical data. Last updated: April 2026

Related Faults

01Power source faulty — RUN LED OFF, TIMER LED flashes 1 time05Wired remote control wiring error — RUN LED OFF, TIMER LED flashes 5 times35Cooling high pressure control activated — RUN LED flashes 3 times, TIMER LED flashes 5 times
Source: Mitsubishi Heavy Industries Air Conditioners
Open Manual (Page 4)Search more codes in this manual