Warning: Disconnect power before servicing.
ErrBase

Daikin Error Codes

Find troubleshooting guides for all Daikin error codes.

28 error codes across 1 appliance types

Minisplit

View all 28 codes →
CodeMeaning
A3A3 on a Daikin mini-split means the condensate drain system has failed and the secondary drain pan float switch has triggered. Daikin indoor units have a primary drain path and a secondary overflow pan with its own float switch as a safety backup.
medium
BLUE-LIGHTThe blue LED on newer Daikin models (Emura, Quaternity) indicates Wi-Fi connectivity status or economy mode activation. A blinking blue light is not an error code on these models.
low
E0E0 is a general safety protection code indicating one of several safety devices in the system has triggered. This is a catch-all code that Daikin uses when a safety switch or sensor has activated but a more specific error code is not available.
high
E11E11 indicates a fault in the coordination between two compressors in a Daikin multi-compressor outdoor unit. This code only appears on larger capacity systems with tandem or twin-rotary compressor configurations.
critical
E3E3 indicates the refrigerant system high-side pressure has exceeded the safe operating limit. The high pressure switch on the outdoor unit has tripped, shutting down the compressor to prevent system damage or safety hazard.
high
E4E4 indicates the refrigerant system low-side pressure has dropped below the safe minimum, triggering the low pressure switch. This typically means refrigerant loss from a leak or a major restriction in the refrigerant circuit.
high
E5E5 indicates the compressor overload relay has tripped, meaning the compressor is drawing more current than its rated capacity for an extended period. This is distinct from L5 (instantaneous trip) - E5 is a sustained overload condition.
high
E6E6 indicates the compressor failed to start or is mechanically locked. The inverter board attempted to energize the compressor but detected no rotation or abnormal current patterns indicating the rotor is not turning.
critical
E7E7 on a Daikin mini-split indicates the outdoor fan motor has failed to start, is running at incorrect speed, or has an electrical fault. Daikin outdoor units use a plastic fan blade mounted on a direct-drive DC motor, and the plastic blade is known to become brittle and crack in cold climates.
high
F3F3 indicates the compressor discharge pipe temperature has exceeded the safe limit, typically above 120C (248F). This protects the compressor from overheating damage. The discharge thermistor mounted on the compressor output pipe monitors this temperature continuously.
high
GREEN-LIGHTThe green LED on a Daikin indoor unit indicates operational status. Different blink patterns have different meanings: steady on or fast blink (2Hz) means the unit is running normally, slow blink (0.5Hz) means standby, and specific blink counts between pauses indicate error codes on models without numeric displays.
low
HUBComplete reference of all Daikin mini-split error codes organized by code prefix. U codes relate to communication and voltage, E codes to compressor and pressure protection, F codes to temperature sensors, L codes to inverter and overcurrent faults, and A codes to drain and airflow issues.
medium
L1L1 indicates a fault on the outdoor unit inverter board itself. The inverter board converts incoming AC power to variable-frequency DC to drive the compressor at different speeds, and L1 triggers when the board detects an internal component failure.
critical
L5L5 indicates an instantaneous overcurrent trip on the compressor circuit. Unlike U0 which builds over time, L5 is a sudden spike that triggers immediate shutdown. This often indicates a phase-to-phase short in the compressor windings or a failed inverter power transistor on the outdoor board.
critical
NOT-COOLINGA Daikin mini-split that runs but does not cool effectively has either an airflow restriction, a refrigerant issue, or a compressor fault. The inverter should modulate compressor speed to match the cooling load.
medium
NOT-COOLINGRefrigerant, Filter, and U4 Diagnosis
medium
NOT-HEATINGA Daikin mini-split not heating can be caused by incorrect mode settings, defrost cycle operation, low refrigerant, outdoor coil ice buildup, or compressor fault. In heat pump mode, the outdoor unit extracts heat from outdoor air - performance decreases as outdoor temperature drops.
medium
NOT-WORKINGA Daikin mini-split that is not working at all could have a power issue, communication fault, or major component failure. This guide covers the complete non-operation scenario where neither indoor nor outdoor unit responds.
high
ORANGE-LIGHTThe orange LED on a Daikin indoor unit serves dual purpose: it indicates timer mode when steady or slow-blinking, and error codes when blinking in counted patterns. A continuously blinking orange light typically means a fault condition.
medium
RED-LIGHTA red LED on a Daikin indoor unit indicates an operation error. The red light is the most serious LED indicator and typically means the unit has detected a fault requiring attention. Count the blink pattern to determine the specific error.
high
RESETResetting a Daikin mini-split clears error codes, restores default settings, or recovers from a frozen control state. Daikin units have multiple reset methods depending on whether you need a soft reset, hard reset, or factory reset.
low
TROUBLESHOOTSystematic troubleshooting guide for Daikin mini-split systems covering the most common issues: not cooling, not heating, error codes, unusual noises, ice buildup, and communication faults between indoor and outdoor units.
medium
U0U0 on a Daikin mini-split signals that the compressor is drawing excessive current, which typically indicates low refrigerant charge or a mechanical compressor fault. Daikin inverter compressors modulate speed continuously, and U0 triggers when current draw exceeds the safe threshold at any operating speed.
high
U2U2 indicates a general power supply voltage fault affecting the entire system. While U9 is specific to the outdoor unit, U2 can trigger from voltage issues at either the indoor or outdoor unit power feed.
medium
U3U3 indicates a temperature sensor (thermistor) on the outdoor unit is reading out of range or has an open/short circuit. Daikin outdoor units have multiple thermistors monitoring ambient temperature, coil temperature, and discharge pipe temperature.
medium
U4U4 on a Daikin mini-split indicates a communication failure between the indoor and outdoor units. Daikin uses a dedicated 2-wire serial bus (S1-S2 terminals) for this communication, and any break in that circuit triggers U4. Unlike Mitsubishi which uses a 3-wire system, Daikin's 2-wire bus is polarity-sensitive on some models.
high
U9U9 indicates the outdoor unit is receiving insufficient voltage to operate safely. Daikin inverter boards have a minimum operating voltage of approximately 187V for 208-230V models, and U9 triggers when voltage drops below this threshold.
medium
WONT-TURN-ONA Daikin mini-split that will not turn on has no response to the remote control and no display on the indoor unit. This is typically a power delivery issue rather than a refrigerant or mechanical fault.
high