Home › Air Conditioners › Daikin

Daikin Air Conditioner Error Codes

Find the code shown on your Daikin air conditioner and get a plain-English explanation with step-by-step fixes, easiest first. We cover 20 Daikin air conditioner codes, including U4, U0, U2, UA.

All 20 Daikin air conditioner codes

• U4Indoor and outdoor units can't communicate
• U0Low refrigerant or restricted refrigerant flow
• U2Power supply voltage problem
• UAIndoor and outdoor units don't match
• A1Indoor unit control board fault
• A3Condensate water level too high
• A5Freeze-up or overheat protection
• A6Indoor fan motor fault
• C4Indoor coil temperature sensor fault
• C9Indoor room air temperature sensor fault
• E1Outdoor unit control board fault
• E5Compressor overload or lock-up protection
• E6Compressor won't start
• E7Outdoor fan motor fault
• E8Compressor current too high
• F3Compressor discharge temperature too high
• F6High pressure in cooling mode
• H6Compressor position sensing error
• L4Inverter heat sink overheating
• L5Inverter output overcurrent

About Daikin air conditioner error codes

Daikin Industries, based in Osaka, Japan, is one of the world's largest air conditioner manufacturers. Daikin codes are usually a letter followed by a number, such as U4 or A5, read from the remote or the indoor unit display.

Of the 20 codes on this page, 0 usually have a simple fix you can do yourself, and 16 usually need a technician. Each guide tells you which is which, so you don't pay for a service call you don't need, and you don't attempt a repair that isn't safe.

Before you start

• Write down your model number. It's on a sticker, usually inside the door or lid, on the frame, or on the back or side panel. Parts and some code meanings depend on it.
• Try a reset. Unplug the air conditioner or switch off its breaker for 10 minutes. This clears many one-off glitches without tools.
• Clean or replace the air filter first. A dirty filter causes many airflow and freezing codes.
• Never open refrigerant lines or electrical panels. Those are jobs for a licensed HVAC technician.