Daikin Air Conditioner Error E4

⚡ Quick Answer: The Daikin Air Conditioner E4 error indicates a communication failure between the indoor and outdoor units, often triggered by excessively low refrige... ⚠️ Difficulty Varies

What Does Error E4 Mean?

The Daikin Air Conditioner E4 error indicates a communication failure between the indoor and outdoor units, often triggered by excessively low refrigerant pressure. This leads to system shutdown, with symptoms including halted operation during heating or cooling and indicator lights flashing on the outdoor unit. Potential causes include refrigerant leaks, a malfunctioning low-pressure switch, or blockages in the refrigerant lines.

Common Symptoms:

  • AC stops operation during heating or cooling
  • Outdoor unit error indicator
  • Potential reduced cooling/heating performance before shutdown

Possible Causes

  • Excessively low refrigerant pressure (refrigerant leak or insufficient refrigerant) (medium)
  • Low‑pressure switch or sensor malfunction (medium)
  • Electronic expansion valve malfunction or blockage in refrigerant lines (medium)

How to Fix Error E4

DIY Fix Basic checks before contacting service

  1. Turn off the unit and allow any ice or frost on the outdoor unit to melt.
  2. Ensure indoor filters are clean and airflow is not restricted.
  3. Verify external unit has adequate ventilation and is free of debris.

Technician Only Professional diagnosis and repair

  1. Check refrigerant pressure with proper gauges and inspect for leaks.
  2. Test low‑pressure switch and sensors for proper function.
  3. Inspect electronic expansion valve and refrigerant lines for blockages or malfunctions.
  4. Repair leaks, replace faulty components, and recharge refrigerant to manufacturer specifications.

Parts needed: Refrigerant, Low‑pressure switch/sensor, Electronic expansion valve, Refrigerant lines/connection fittings

🛑 When to Call a Pro:
  • If error persists after basic checks
  • If refrigerant leak is suspected
  • If outdoor unit shows ice buildup or abnormal noises

Next step

Choose the next step for E4

Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.

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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.

Maintenance supply

Air Conditioner Fin Cleaner

For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.

View maintenance supply
Maintenance supply

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.

Find one that fits my model

Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.

Technical Specifications

note The previous model-independent part specification was removed. Verify the full model number and diagnosis in the manufacturer's official parts catalog before ordering.
part_number None

Common Questions

What does E4 error mean on Daikin Air Conditioner?

E4 error signifies a communication failure due to low refrigerant pressure, stopping the AC operation.

Can I fix Daikin Air Conditioner E4 error myself?

You can check for ice buildup, clean filters, and ensure proper ventilation, but professional help is advised for leaks.

How much does it cost to fix E4 error?

Repair costs vary widely; refrigerant recharge and leak repairs can be several tens of thousands JPY or more.

When should I call a technician for E4?

Call a technician if the error persists after basic checks, if a refrigerant leak is suspected, or if you notice ice buildup.

Sources & References

Data last verified: 2026-07-31

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