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Home > Error Codes > Daikin Ductless

Daikin Ductless Mini-Split Error Codes — Complete Guide

Daikin ductless systems use U, A, E, F, H, J, and L prefixed codes. These appear on the indoor unit display or via LED blink patterns.

How to read Daikin error codes:
Daikin mini-splits display alphanumeric codes on the indoor unit LCD panel or wireless remote. Some wall-mount units use green LED blink patterns. Press the cancel button 5 times to enter diagnostic mode on some models.

U Codes (Protection / Safety)

U0

Low Refrigerant / Low Pressure

System pressure is too low. Usually indicates a refrigerant leak.

DIY check: Requires a licensed technician with gauges to check refrigerant and find leaks.

U2

Abnormal Power Supply

The power supply voltage is outside acceptable range or has a wiring issue.

DIY check: Check voltage at the disconnect. Ensure proper wiring polarity.

U4

Communication Error (Indoor/Outdoor)

Communication failure between indoor and outdoor units.

DIY check: Check communication wiring. Power cycle both units.

U9

Communication Error (Same System)

In multi-zone systems, communication failure between multiple indoor units or between indoor and branch box.

DIY check: Check all wiring connections in the system. Power cycle.

A Codes (Air / Sensor)

A1

Indoor PCB Defect

The indoor unit control board has a fault.

DIY check: Power cycle. Board replacement if persistent.

A3

Drain Level Abnormal

Condensate drain is clogged or drain pan is full.

DIY check: Clear the condensate drain line. Clean the drain pan.

A5

Freeze / Overheat Protection

Indoor coil is freezing or overheating. Usually caused by dirty filters or restricted airflow.

DIY check: Clean or replace the air filter. Ensure indoor vents are not blocked.

A6

Indoor Fan Motor Error

Indoor fan motor is not running correctly.

DIY check: Clean the blower wheel. Check for obstructions. Power cycle.

E Codes (Compressor / Outdoor)

E1

Outdoor PCB Defect

The outdoor unit control board has failed.

DIY check: Power cycle. Board replacement needed (technician).

E5

Compressor Overload

The compressor is overloaded. Could be dirty coils, low refrigerant, or compressor failure.

DIY check: Clean outdoor coil. If persistent, technician needed for compressor diagnosis.

E7

Outdoor Fan Motor Error

The outdoor fan motor has failed or is blocked.

DIY check: Check for physical blockages at the outdoor fan. Motor replacement if needed.

Other Common Daikin Codes

F3

Discharge Pipe Temp Too High

Compressor discharge temperature is dangerously high. Low refrigerant or compressor issue.

DIY check: Requires technician. Do not run the system with F3 active.

H6

Position Detection Sensor Error

Compressor position sensor has failed (inverter models).

DIY check: Power cycle. Technician needed for sensor/board work.

L3

Electrical Parts High Temp

The electrical components in the outdoor unit are overheating. Could be poor ventilation or component failure.

DIY check: Ensure outdoor unit has clearance. Clean the unit. Shade from direct sun if possible.

FAQ

How do I reset my Daikin mini-split?
Turn off at the breaker for 30+ seconds. Some Daikin models also have a reset button on the indoor unit. The error clears on restart if the issue is resolved.
My Daikin shows U4 repeatedly. What should I check?
U4 is a communication error between indoor and outdoor units. Check: the communication wire for damage, all connector terminals are tight, and both units have power. Multi-zone systems are more prone to U4 if branch box wiring is loose.
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