ErrorCodeDoctor
Daikin · Air Conditioner

Daikin Air Conditioner L4 error code

Difficulty: Medium · Cost: $0–$350 · Duration: 15–20m

The L4 error means your Daikin air conditioner detected that the inverter PCB's radiation fin temperature rose to an abnormal level. This is often caused by insufficient airflow around the outdoor unit or a defective fin thermistor. Make sure the outdoor unit has adequate clearance on all sides. If the error persists contact a qualified technician.

Common causes

  • Radiation fin temperature rose due to a short circuit in airflow around the outdoor unit
  • Fin thermistor is defective
  • Inverter compressor has a fault

How to fix it

  1. 1

    Turn off the air conditioner and allow the outdoor unit to cool down

  2. 2

    Check that the outdoor unit has adequate clearance on all sides for airflow — remove any objects, debris, or plants blocking the unit

  3. 3

    Make sure the outdoor unit is not in direct sun with no airflow

  4. 4

    Restart and check if L4 returns

  5. 5

    If L4 persists contact a qualified technician to inspect the inverter fin thermistor

Related Daikin Air Conditioner error codes

1

A0

An external protection device connected to the indoor unit has been activated

hard
2

A1

A fault was detected in the indoor unit PCB (control board)

hard
3

A3

The drain level control system has detected an abnormality — drain may be clogged

medium
4

A5

Freeze-up protection (cooling) or high pressure control (heating) has activated — check the air filter

easy

L4 error — frequently asked questions

What does the L4 error mean on a Daikin air conditioner?

The inverter radiation fin temperature rose abnormally

What causes the L4 error?

The L4 error is usually caused by: Radiation fin temperature rose due to a short circuit in airflow around the outdoor unit; Fin thermistor is defective; Inverter compressor has a fault.

Can I fix the L4 error myself?

It's possible for a moderately handy person, but budget 15–20m and expect some disassembly.

How much does it cost to fix the L4 error?

Fixing the L4 error on a Daikin air conditioner typically costs $0–$350, depending on parts and whether you do it yourself or hire a technician.

Is it safe to keep using my air conditioner with the L4 error?

In most cases yes, but it's best to address the L4 error soon — see the fix steps below to resolve it.