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E54 / Outdoor Red LED 2 flashes

Error E54 / Outdoor Red LED Flashes Twice — Pressure sensor error

Mitsubishi Heavy Industries · Air Conditioners

What does E54 / Outdoor Red LED 2 flashes mean?

Error E54, indicated by two flashes of the outdoor unit's red LED, points to a general pressure sensor issue. This could be related to either low or high pressure sensors.

Common Causes

  • Low pressure sensor (PSL) disconnection/output error
  • High pressure sensor (PSH) disconnection/output error

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Turn off the main power supply to the outdoor unit.

  2. 2

    Inspect the connections of both the low pressure (PSL) and high pressure (PSH) sensors to the outdoor PCB.

  3. 3

    Ensure the connectors are firmly seated and free from corrosion.

  4. 4

    Check the refrigerant lines for any visible signs of leakage or damage.

  5. 5

    Contact a professional technician to perform system pressure checks and sensor diagnostics.

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
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