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Operation 4 Times / Timer 0A

Operation LED blinks 4 times and Timer LED shows 0A — Outdoor temperature thermistor error.

Fujitsu · 410A Multi-Zone Mini-Split Systems

What does Operation 4 Times / Timer 0A mean?

The thermistor measuring the outdoor ambient temperature is reporting an abnormal reading.

Common Causes

  • The outdoor temperature thermistor is open (disconnected) or shorted (faulty connection).
  • The controller PCB is defective.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power off the unit at the circuit breaker.

  2. 2

    Visually inspect the outdoor temperature thermistor for any visible damage or loose connections.

  3. 3

    Ensure the thermistor is correctly positioned and not dislodged.

  4. 4

    If the error persists, a technician should check the thermistor's resistance or the controller PCB.

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

Related Faults

6 Times, 4 Times Continuous (64)6 Times, 4 Times Continuous (64) — Active Filter / PFC Circuit error6 Times, 5 Times Continuous (65)6 Times, 5 Times Continuous (65) — IPM error / Trip terminal L error7 Times, 1 Time Continuous (71)7 Times, 1 Time Continuous (71) — Discharge thermistor error
Source: Fujitsu 410A Multi-Zone Mini-Split Systems
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