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Mini-Split Error Codes: Complete Guide by Brand (2026)

by Dua Jones April 14, 2026

When a mini-split detects a problem, it displays an error code on the indoor unit, remote control, or LED indicator light. These codes vary by manufacturer. This guide covers the most common error codes for the major mini-split brands sold in the US and Canada, along with what each code typically indicates and the first steps you should take.

Before You Start Many error codes can be cleared by turning off the mini-split at the breaker for 30 seconds and restarting. If the code returns, the underlying issue likely needs diagnosis. Always consult your owner's manual for brand-specific instructions, and contact a licensed HVAC technician for refrigerant, electrical, or compressor issues.

Mitsubishi Mini-Split Error Codes

Mitsubishi units display error codes on the remote or through blinking LED patterns on the indoor unit. According to Mitsubishi Electric's published service documentation, the most frequently encountered codes include:

Code	Meaning	Common Cause	First Step
E6	Indoor/outdoor communication error	Wiring issue or control board failure	Check wiring connections between units
P8	Condenser pipe temperature abnormality	Refrigerant issue or blocked airflow	Clean outdoor coil; call technician if persists
U4	Communication error (multi-zone)	Loose signal wire between units	Inspect signal wiring at both units
E1	Remote control signal issue	IR sensor blocked or remote malfunction	Replace remote batteries; clear line of sight
P6	Freeze/overheat protection activated	Dirty filter, low refrigerant, or blocked coil	Clean filter and coils; reset unit

For a full list, see our dedicated Mitsubishi error codes guide.

Fujitsu Mini-Split Error Codes

Fujitsu mini-splits typically indicate errors through blinking LED lights (operation, timer, and economy lights) as well as alphanumeric codes on wired controllers.

Code	Meaning	Common Cause	First Step
EE:EE	General communication error	Signal wire disconnected or damaged	Power cycle unit; inspect wiring
E1:00	Indoor unit communication failure	Loose connector on PCB board	Check board connections; call tech
E3:00	High-pressure protection	Dirty outdoor coil or overcharge	Clean outdoor coil; ensure airflow
E9:00	Drain error	Clogged condensate drain line	Clear drain line; check drain pump

Full breakdown: Fujitsu error codes guide.

Daikin Mini-Split Error Codes

Daikin units show error codes on the remote controller display or through LED blinks on the indoor unit.

Code	Meaning	Common Cause	First Step
U0	Low refrigerant or gas leak detected	Refrigerant leak in line set or coils	Call licensed HVAC tech for leak test
E7	Outdoor fan motor malfunction	Fan motor failure or wiring issue	Inspect outdoor fan; call technician
A3	Drain malfunction	Clogged drain line	Clear condensate drain line
L5	Compressor overcurrent	Electrical issue or compressor failure	Check breaker; call technician

Full breakdown: Daikin error codes guide.

LG Mini-Split Error Codes

LG mini-splits display codes on the indoor unit's LED display or via the remote.

Code	Meaning	Common Cause	First Step
CH 05	Communication error	Wiring between indoor and outdoor unit	Inspect signal wire connections
CH 10	Indoor fan motor issue	Motor failure or blockage	Check for obstructions; call tech
CH 21	Compressor overcurrent	Electrical overload	Check breaker; call technician
CH 26	Condenser temperature sensor fault	Failed sensor	Sensor replacement needed

Full breakdown: LG error codes guide.

MrCool Mini-Split Error Codes

MrCool units — popular in the DIY market — use standard error code conventions shared with several Chinese-manufactured brands.

Code	Meaning	Common Cause	First Step
E1	Indoor temperature sensor fault	Disconnected or failed thermistor	Check sensor wiring; replace if faulty
E4	Outdoor temperature sensor fault	Damaged sensor wire	Inspect sensor on outdoor coil
F1	Indoor coil sensor fault	Failed sensor	Replace coil temperature sensor
H6	Indoor fan motor feedback error	Fan motor not spinning or blocked	Clear obstructions; check motor

Full breakdown: MrCool error codes guide.

Gree, Pioneer, and Midea Error Codes

Gree, Pioneer, and Midea share many common error codes, as Pioneer and many Midea units use Gree-manufactured compressors and control boards.

Code	Meaning	Common Cause	First Step
E1	High-pressure protection	Dirty outdoor coil or overcharge	Clean outdoor coil; ensure airflow
E2	Anti-freeze protection	Dirty filter, low refrigerant	Clean filter; check refrigerant
E4	Compressor discharge temp too high	Low refrigerant or compressor issue	Call technician for diagnosis
E6	Communication error	Signal wire fault	Check wiring between units
F1	Indoor coil sensor fault	Failed thermistor	Replace sensor
H6	Indoor fan motor error	Motor stuck or failed	Check for obstructions; test motor

Carrier and Bosch Error Codes

Brand	Code	Meaning	First Step
Carrier	E1	Room temperature sensor error	Check sensor connection
Carrier	E5	Communication error	Inspect signal wiring
Carrier	F4	Outdoor discharge temp sensor	Call technician
Bosch	E1	Indoor sensor fault	Check thermistor wiring
Bosch	E4	Outdoor sensor fault	Inspect outdoor coil sensor
Bosch	F0	Refrigerant leak detected	Call licensed tech immediately

Universal Error Codes: E1, E4, F1, H6

Several error codes appear across multiple brands because many manufacturers use similar control board architectures. Here is what each common code typically means, regardless of brand:

E1 — Usually a temperature sensor fault (indoor) or high-pressure protection. In most cases, the first step is to check whether the air filter is clean and whether airflow to the outdoor unit is unobstructed.

E4 — Typically relates to the outdoor unit: compressor discharge temperature too high or outdoor coil sensor fault. Often caused by low refrigerant, a dirty outdoor coil, or restricted airflow around the outdoor unit.

F1 — Indoor evaporator coil temperature sensor failure. This sensor monitors the coil to prevent freezing. If the sensor fails, the unit cannot regulate properly. Replacement is straightforward for a technician.

H6 — Indoor fan motor not sending a speed feedback signal to the control board. This can be caused by a stuck fan blade, a failed motor, or a wiring issue. Check for physical obstructions first.

When to Call a Professional You can safely handle error codes related to dirty filters, clogged drains, and communication wiring (visual inspection only). Any code involving refrigerant, compressor issues, high pressure, or electrical faults should be diagnosed by a licensed HVAC technician. Refrigerant handling requires EPA Section 608 certification in the US.

Frequently Asked Questions

How do I clear an error code on my mini-split?

Turn off the unit at the breaker (not just the remote) for 30 seconds, then turn it back on. If the error code reappears, the underlying problem still exists and needs to be addressed.

My error code is not in this list — what should I do?

Check your owner's manual or the manufacturer's website for the full error code reference for your specific model. You can also search our brand-specific error code guides linked above for a more complete listing.

Are error codes the same across all models from one brand?

Most brands keep error codes consistent across their mini-split product lines, but some newer models or specialized units may have additional codes. Always cross-reference with the documentation that came with your specific unit.