Haier mini split error codes

Haier multi-zone ductless systems (sold in the US alongside the identical GE Appliances units) show numeric codes on the Service Monitor Board inside the outdoor unit. Haier single-zone units use a different table not covered here yet.

Covers: Haier Flexfit multi-zone (2U/3U/4U…MS2HDA).

Most looked-up Haier codes

15Communication error between indoor and outdoor units 16Lack of refrigerant 9Outdoor fan motor fault 2IPM (inverter power module) fault 5Compressor overload protection 42High pressure switch open 43Low pressure switch open 21Indoor coil frosted (freeze protection)

All Haier codes

40 codes. Type to filter the list.

Filter codes

Code	Meaning	Type	Fix
1	Outdoor PCB EEPROM fault	Fault	Technician
2	IPM (inverter power module) fault	Protection	Technician
4	Communication failure between IPM and outdoor PCB	Fault	Technician
5	Compressor overload protection	Protection	DIY checks
6	Unreliable power input (voltage protection)	Protection	DIY checks
8	Compressor discharge temperature too high	Protection	DIY checks
9	Outdoor fan motor fault	Fault	DIY checks
10	Defrost (outdoor coil) temperature sensor fault (open or short circuit)	Fault	DIY checks
11	Compressor suction temperature sensor fault (open or short circuit)	Fault	DIY checks
12	Outdoor ambient temperature sensor fault (open or short circuit)	Fault	DIY checks
13	Compressor discharge temperature sensor fault (open or short circuit)	Fault	DIY checks
15	Communication error between indoor and outdoor units	Fault	DIY checks
16	Lack of refrigerant	Fault	DIY checks
17	Four-way (reversing) valve switching failure	Fault	Technician
18	Compressor out of synchronism	Protection	Technician
20	Indoor thermal overload (heating)	Protection	DIY
21	Indoor coil frosted (freeze protection)	Protection	DIY
23	IPM temperature too high	Protection	DIY checks
24	Compressor start failure	Protection	Technician
25	IPM current too high	Protection	Technician
26	Outdoor PCB reset	Status	DIY
27	IPM current detection circuit malfunction	Fault	Technician
28	Zone A indoor unit liquid pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
29	Zone B indoor unit liquid pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
30	Zone C indoor unit liquid pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
31	Zone D indoor unit liquid pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
32	Zone A indoor unit gas pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
33	Zone B indoor unit gas pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
34	Zone C indoor unit gas pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
35	Zone D indoor unit gas pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
36	Zone E indoor unit gas pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
38	IPM temperature sensor fault or momentary power failure detected	Fault	Technician
39	Condensing (outdoor coil) temperature sensor fault (open or short circuit)	Fault	DIY checks
40	Zone E indoor unit liquid pipe temperature sensor fault (open or short circuit)	Fault	DIY checks
41	Compressor top (Toci) temperature sensor fault (open or short circuit)	Fault	DIY checks
42	High pressure switch open	Protection	DIY checks
43	Low pressure switch open	Protection	DIY checks
44	High pressure detected in system	Protection	DIY checks
45	Low pressure detected in system	Protection	DIY checks
Lo	Outdoor temperature below operating range	Status	DIY

How Haier shows error codes

These numeric codes show on the Service Monitor Board display inside the multi-zone OUTDOOR unit (behind the service panel). The indoor units signal a fault with blinking lamps; the number on the outdoor board is what identifies it. Codes 1 to 27 are outdoor-unit faults and protections, 28 to 41 are temperature sensors (28 to 31 and 40 are zone liquid-pipe sensors, 32 to 36 are zone gas-pipe sensors), and 42 to 45 are pressure switches and limits.

Brands built on the same platform

These brands share a code table with Haier because the same factory builds them, so their pages describe the same faults: GE Appliances.

Sources

Haier / GE Ductless Multi-Split Heat Pump Service Manual (4.11.22), Error Codes table

Updated September 2026. Manufacturer site: www.haierappliances.com