Split AC Error Codes – acerrorcodes.com

Before you search: the same letter-number code can mean different things across a brand’s own model years. Treat the descriptions below as a strong first guess, then confirm against the sticker inside the indoor unit’s front panel or your model’s manual.

Safety first: burning smell, sparking, or a tripped breaker means a possible short circuit — cut power at the main board and call an electrician. Suspected gas leakage or refrigerant faults need a certified technician with proper equipment. See the full disclaimer before acting on any code.

LGLG›

Code	Likely meaning	What to check
CH 01	Indoor unit fan motor malfunction	Fan motor obstruction or wiring; often needs a technician if the fan doesn’t spin at all.
CH 02	Indoor unit EEPROM (memory) error	Indoor PCB fault — usually needs PCB reset or replacement.
CH 04	Outdoor unit compressor discharge protection	Check outdoor unit airflow and refrigerant level isn’t low.
CH 05	Communication error between indoor and outdoor unit	Inspect the connecting cable between units for damage or loose terminals.
CH 06	Zero-cross detection error at the outdoor unit	Outdoor PCB issue; usually not user-fixable.
CH 21	Indoor and outdoor unit capacity mismatch	Confirm the indoor and outdoor unit are a matched pair (post-repair swap issue).
E1	Room temperature sensor open or short (older non-inverter models)	Sensor connector may be loose behind the front panel.
CH 07	Outdoor unit temperature sensor error	Check the outdoor sensor connector and wiring.
CH 09	Outdoor unit compressor overcurrent	Check outdoor unit ventilation and load on the compressor.
CH 10	Outdoor unit EEPROM (memory) error	Outdoor PCB fault, usually needs board service.
CH 38	Outdoor unit high pressure protection	Clean the outdoor coil and check for restricted airflow.

SSSamsung›

Code	Likely meaning	What to check
E101	Communication error between indoor and outdoor PCB	Check the inter-unit cable and both PCB connectors.
E162	Outdoor temperature sensor error	Sensor may be disconnected or damaged at the outdoor unit.
E181	Indoor unit EEPROM error	Indoor PCB fault — typically needs replacement.
E201	Indoor fan motor error	Check for a jammed fan blade or failed motor.
E203	Outdoor fan motor error	Debris around the outdoor fan, or motor winding failure.
E422	Drain pump or float switch error	Check the condensate drain line isn’t blocked.
E211	Indoor unit EEPROM checksum error	Indoor PCB fault — usually needs board service.
E251	Outdoor unit high pressure switch trip	Clean the outdoor coil and check airflow clearance.
E252	Outdoor unit low pressure switch trip	Possible refrigerant shortage — needs gauge check.
E469	Outdoor unit compressor overcurrent	Check outdoor unit load and ventilation clearance.

DKDaikin›

Code	Likely meaning	What to check
U0	Refrigerant shortage detected	Possible gas leak — needs a technician with gauges, not a DIY top-up.
U2	Power supply voltage abnormality	Check incoming voltage and connections at the isolator switch.
U4	Communication error between indoor and outdoor unit	Inspect the interconnecting wiring for loose or corroded terminals.
A1	Indoor PCB defect	Usually requires indoor board replacement.
A6	Indoor fan motor lock or overload	Check for obstruction in the fan housing.
E5	Compressor overload / thermal protection tripped	Check outdoor unit ventilation and clean the condenser coil.
E7	Outdoor fan motor error	Check for obstruction or motor failure at the outdoor fan.
H3	High pressure switch activated	Dirty outdoor coil or restricted airflow around the outdoor unit.
A9	Electronic expansion valve abnormality	Indoor unit fault — needs technician diagnosis.
C4	Indoor heat exchanger sensor error	Check the indoor coil sensor connection.
C9	Indoor suction air sensor error	Check the suction air sensor wiring.

VTVoltas›

Code	Likely meaning	What to check
F1	Indoor room temperature sensor error	Sensor connector loose behind the indoor front panel.
F2	Indoor coil temperature sensor error	Check the coil sensor clip and wiring.
F3	Outdoor coil temperature sensor error	Sensor damage at the outdoor coil.
F4	Outdoor discharge temperature sensor error	Compressor discharge sensor fault — technician required.
F5	Communication error between indoor and outdoor unit	Check the connecting cable and terminal block.
F6	EEPROM (memory) error	PCB fault, usually needs board service.
F8	Overload or high-pressure protection	Clean the outdoor condenser and check for blocked airflow.
F9	Outdoor fan motor fault	Check the outdoor fan for obstruction or motor failure.
F0	Refrigerant leak detected	Needs a technician with gauges — do not attempt a DIY gas top-up.
F7	Outdoor ambient temperature sensor error	Check the outdoor ambient sensor connection.

BSBlue Star›

Code	Likely meaning	What to check
E1	Indoor room temperature sensor error	Sensor wiring loose inside the indoor unit.
E2	Indoor coil sensor error	Check the coil sensor position and connection.
E4	Communication error	Check the inter-unit cable between indoor and outdoor.
E7	Outdoor unit general fault	Requires technician inspection of the outdoor PCB.
P1	High pressure protection tripped	Clean the outdoor coil and check for restricted airflow.
P4	Compressor overload protection	Check outdoor unit ventilation clearance.
E3	EEPROM (memory) error	PCB fault, usually needs board service.
E5	Outdoor sensor error	Check outdoor sensor wiring and connector.
E8	Compressor overcurrent protection	Check outdoor unit load and ventilation clearance.
P2	Low pressure protection tripped	Possible refrigerant shortage — needs gauge check.

HTHitachi (blink-pattern models)›

Many Hitachi split ACs don’t show a text code — they blink the operation lamp a set number of times, then pause and repeat.

Blinks	Likely meaning	What to check
1	Indoor unit PCB error	Indoor board fault, needs service.
2	Indoor fan motor error	Check for obstruction or a failed motor.
3	Communication error between units	Inspect the connecting cable.
5	Indoor coil sensor error	Check coil sensor connection.
7	Drain pump error	Check the condensate drain for blockage.
4	Outdoor unit EEPROM error	Outdoor PCB fault, usually needs board service.
6	Outdoor fan motor error	Check for obstruction or motor failure at the outdoor fan.
8	Compressor overload protection	Check outdoor unit ventilation and coil cleanliness.
9	High pressure protection	Clean the outdoor coil and check airflow clearance.
10	Low pressure protection	Possible refrigerant shortage — needs gauge check.

PNPanasonic›

Code	Likely meaning	What to check
H11	Communication error between indoor and outdoor unit	Check the interconnecting wiring.
H14	Indoor temperature sensor error	Sensor connector loose inside the indoor unit.
H15	Compressor temperature sensor error	Outdoor sensor fault, needs technician.
H97	Outdoor fan motor error	Check for obstruction at the outdoor fan.
H99	Outdoor unit PCB error	Outdoor board fault, needs service.
U04	No communication between indoor and outdoor unit	Check the connecting cable and terminals.
H23	Indoor coil sensor error	Check the indoor coil sensor clip and connection.
F94	Outdoor unit high pressure protection	Clean the outdoor coil and check airflow clearance.
F95	Outdoor unit low pressure protection	Possible refrigerant shortage — needs gauge check.
U02	Power supply voltage synchronization error	Check incoming voltage at the isolator switch.

GJGodrej›

Code	Likely meaning	What to check
E1	Room temperature sensor error	Check the sensor connector behind the front panel.
E2	Coil temperature sensor error	Check the coil sensor clip position.
E3	Communication error	Inspect the inter-unit cable.
E4	Overload protection tripped	Check outdoor unit airflow and coil cleanliness.
E5	EEPROM (memory) error	PCB fault, usually needs service.
E6	Outdoor fan motor error	Check for obstruction or motor failure at the outdoor fan.
E7	Outdoor unit overload protection	Check outdoor unit ventilation clearance.
E8	High pressure protection tripped	Clean the outdoor coil and check for restricted airflow.
E9	Low pressure protection tripped	Possible refrigerant shortage — needs gauge check.
E10	Outdoor unit PCB fault	Outdoor board fault, needs service.

WPWhirlpool›

Code	Likely meaning	What to check
E1	Room temperature sensor error	Sensor wiring loose inside the indoor unit.
E2	Coil temperature sensor error	Check the coil sensor connection.
E4	Overload trip	Check outdoor unit ventilation clearance.
E5	Communication failure between units	Inspect the connecting cable.
E6	Outdoor fan motor error	Check for obstruction or motor failure at the outdoor fan.
E7	High pressure protection	Clean the outdoor coil and check airflow clearance.
E8	Low pressure protection	Possible refrigerant shortage — needs gauge check.
E9	Outdoor unit PCB fault	Outdoor board fault, needs service.
E10	Compressor overload protection	Check outdoor unit ventilation clearance.
E11	Refrigerant leak detected	Needs a technician with gauges — not a DIY fix.

TRTrane (North America)›

Code	Likely meaning	What to check
E1	High pressure protection	Clean outdoor coil and check airflow clearance.
E2	Low pressure protection	Possible refrigerant shortage — needs gauge check.
E3	Indoor coil sensor error	Check the indoor coil sensor connection.
E4	Outdoor coil sensor error	Check the outdoor coil sensor connection.
E5	Compressor overload protection	Check outdoor unit ventilation clearance.
E6	Communication error between indoor and outdoor unit	Inspect the connecting cable and terminals.
E7	Indoor fan motor error	Check for obstruction or a failed motor.
E8	Outdoor fan motor error	Check for obstruction or motor failure at the outdoor fan.
E9	EEPROM (memory) error	PCB fault, usually needs board service.
E10	Power supply voltage abnormality	Check incoming voltage and connections.

FGFujitsu General (global)›

Code	Likely meaning	What to check
E1	Indoor unit signal reception error	Check remote control batteries and signal path.
E4	Communication error between indoor and outdoor unit	Inspect the interconnecting wiring.
E5	Compressor overcurrent	Check outdoor unit load and ventilation clearance.
E6	Outdoor fan motor error	Check for obstruction or motor failure.
E8	Indoor fan motor error	Check for obstruction or a failed motor.
E9	Indoor unit EEPROM error	Indoor PCB fault, usually needs board service.
EA	Outdoor unit operating mode conflict	Check for a mismatched or shared outdoor unit setting.
EE	Drain pump / float switch error	Check the condensate drain for blockage.
F3	High pressure protection	Clean the outdoor coil and check airflow clearance.
F0	Refrigerant sensor abnormality	Possible refrigerant issue — needs technician check.

Looking for a ductable, cassette, tower or VRF system instead? Those are covered on the commercial & VRF page. Single-unit room ACs are on the window AC page.

Split AC error codes, brand by brand.