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
- Ensure outdoor unit has no obstructions (clear away objects blocking airflow).
- Inspect that outdoor fan is running during operation (visual check).
- 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
- Use service tools to measure outdoor heat sink temperature and verify thermistor readings.
- Check outdoor fan motor operation, fan blade condition, and airflow.
- Inspect and test fin thermistor/temperature sensor and connections for correct function.
- 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)
- 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
Next step
Choose the next step for L4-00
Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.
Most relevant component to inspect
Thermistor
Measures precise temperature changes and sends resistance feedback to the control board.
- Typical part-only price
- $15 - $35
- DIY difficulty
- Easy
- Estimated time
- 15-30 mins
Where can I find the model number?
Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.
Verify the complete model and part number on the retailer's compatibility page before ordering.
Other parts options
Check related components first; use model search as a fallback.
Temperature Sensor
Monitors the internal temperature to ensure correct operation and prevent overheating.
HVAC Control Board
Controls fan, compressor, sensor, and communication functions in the HVAC unit.
Model-compatible Air Conditioner parts
Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. We may earn a commission from other qualifying purchases or service requests made through links on this page, at no additional cost to you. Recommendations are based on repair relevance, not commission rate.
Optional routine care
Maintenance supplies
These products support cleaning or routine upkeep. They are separate from the possible repair components above and are not claimed to fix this error code or symptom.
Air Conditioner Fin Cleaner
For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.
Model-Compatible Washable AC Filter
A reusable filter option only where the appliance supports one. Match the full model, dimensions, and filter specification.
Compatibility check required: use the complete appliance model and compare the existing filter, bag, or specification before ordering.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.
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: 2026-07-25
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