Daikin Air Conditioner Error L4-00

⚡ Quick Answer: The Daikin air conditioner L4-00 error indicates a communication failure between the indoor and outdoor units, primarily due to an over-temperature co... ✅ DIY Fixable

What Does Error L4-00 Mean?

The Daikin air conditioner L4-00 error indicates a communication failure between the indoor and outdoor units, primarily due to an over-temperature condition at the outdoor unit's heat dissipation fin. This protective measure prevents the system from operating to avoid damage. Symptoms include the outdoor unit stopping during operation, high temperatures at the heat sink, and possible fan malfunctions. Ensuring proper airflow and checking for obstructions are critical initial steps to address this issue.

Common Symptoms:

  • Outdoor unit stops running during operation
  • High temperature at outdoor unit heat sink or fins
  • Possible outdoor fan not operating or insufficient cooling airflow

Possible Causes

  • Over‑temperature at outdoor unit heat dissipation fin (heat sink) (medium)
  • Outdoor fan motor malfunction or inadequate cooling airflow (medium)
  • Faulty fin thermistor or temperature sensor or its connection (medium)
  • Control board (PCB) issue related to sensor interpretation (low)

How to Fix Error L4-00

DIY Fix Initial Checks and Safe Reset

  1. Ensure outdoor unit has no obstructions (clear away objects blocking airflow).
  2. Inspect that outdoor fan is running during operation (visual check).
  3. Turn off the air conditioner at the breaker or unplug for ~1 minute, then restore power and attempt operation.

Technician Only Professional Diagnosis and Repair

  1. Use service tools to measure outdoor heat sink temperature and verify thermistor readings.
  2. Check outdoor fan motor operation, fan blade condition, and airflow.
  3. Inspect and test fin thermistor/temperature sensor and connections for correct function.
  4. Examine outdoor unit control board (PCB) for faults, bad solder joints, or heat damage.

Parts needed: Fin thermistor/temperature sensor, Outdoor fan motor or fan assembly, Outdoor unit control board (PCB)

🛑 When to Call a Pro:
  • If error persists after initial safe reset
  • If outdoor fan does not run or unusual noises are present
  • If you are uncomfortable inspecting unit due to electrical hazards

Technical Specifications

wattage
component Communication Cable
resistance
part_number
voltage_rating 220V AC

Common Questions

What does L4-00 error mean on daikin air conditioner?

L4-00 indicates a communication failure due to over-temperature at the outdoor unit, causing it to stop operating.

Can I fix daikin air conditioner L4-00 error myself?

Yes, check for obstructions, ensure the outdoor fan is running, and perform a safe reset by turning off the power.

How much does it cost to fix L4-00 error?

Repair costs for the L4-00 error range from ¥20,000 to ¥80,000, depending on the repairs needed.

When should I call a technician for L4-00?

Call a technician if the error persists after a reset, if the outdoor fan doesn't run, or if you're uncomfortable with electrical inspections.

Data last verified: 2026-07-01

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