E54

Low/High Pressure Sensor Disconnection/Output Error

Mitsubishi Electric · FR-D700 Inverter

What does E54 mean?

This error indicates a disconnection or output error with either the low-pressure sensor (PSL) (E54-1) or the high-pressure sensor (PSH) (E54-2). This prevents accurate pressure monitoring, jeopardizing system safety and control.

Common Causes

  • Disconnection of the low or high-pressure sensor.
  • Pressure sensor outputting an invalid signal, possibly due to internal failure.
  • Faulty wiring harness between the pressure sensor and the control board.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the low-pressure sensor (PSL) and high-pressure sensor (PSH) connections for security and physical damage.

  2. 2

    Measure the output voltage or resistance of both PSL and PSH sensors and compare to specification.

  3. 3

    Verify the wiring continuity from the sensors to the outdoor unit PCB, checking for breaks or short circuits.

Browse all codes in this manual (78)
Verified technical data. Last updated: March 2026

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Source: Mitsubishi Electric FR-D700 Inverter