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J4

J4 - Failed outdoor coil vapour sensor

Daikin · Air Conditioning

What does J4 mean?

The sensor for the outdoor coil's vapour line has an open or short circuit.

Common Causes

  • Outdoor coil vapour sensor open or short circuit.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Check the connection of the outdoor coil vapour sensor.

  2. 2

    Inspect the sensor and its associated wiring for damage.

  3. 3

    If the sensor or wiring is faulty, a professional must replace it.

Browse all codes in this manual (79)
Verified technical data. Last updated: April 2026

Related Faults

A0A0 - External protection activeA1A1 - Indoor PCB failureA2A2 - Malfunction of freezing protection
Source: Daikin Air Conditioning
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