DIY HVAC Tools

ACiQ mini split error codes

ACiQ, the house brand sold by Ingram's Water & Air, uses two makers. The standard single-zone and multi-zone lines are Midea-built and show the Midea code set; the K-series (model numbers with a K after ACiQ) is TCL-built and shows the TCL set. E1, E4 and E5 exist on both with different meanings, so check the model number on the indoor unit's label.

Covers: Standard single-zone (ACiQ-09Z-HP…B / W-HP) and multi-zone, K-series (ACiQ-K09W-HP…, SZDM / WHP / KZHP).

Type it exactly as the unit shows it. Not sure which brand? It is printed on the front of the indoor unit.

Most looked-up ACiQ codes

E1Communication error between indoor and outdoor units / Indoor room temperature sensor fault (open or short circuit)E0Indoor unit EEPROM parameter error / Communication error between indoor and outdoor unitsE5Evaporator coil temperature sensor (T2) open or short circuit / Model configuration or mismatch errorECRefrigerant leak detected (low refrigerant charge) / Outdoor module communication faultE4Indoor room temperature sensor (T1) open or short circuit / Abnormal system operation or lack of refrigerantP4Inverter compressor drive error / Excessive outdoor discharge temperatureE9Outdoor IPM or compressor drive fault

All ACiQ codes

62 codes. Type to filter the list.

CodeMeaningTypeFix
E0standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Indoor unit EEPROM parameter error
K-series (ACiQ-K09W-HP…, TCL-built): Communication error between indoor and outdoor units		FaultDIY checks
E1standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Communication error between indoor and outdoor units
K-series (ACiQ-K09W-HP…, TCL-built): Indoor room temperature sensor fault (open or short circuit)		FaultDIY checks
E2standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Zero-crossing signal detection error
K-series (ACiQ-K09W-HP…, TCL-built): Indoor fan coil (evaporator) temperature sensor fault (open or short circuit)		FaultDIY checks
E3standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Indoor fan speed out of control (indoor fan motor fault)
K-series (ACiQ-K09W-HP…, TCL-built): Outdoor fan coil (condenser) temperature sensor fault (open or short circuit)		FaultDIY checks
E4standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Indoor room temperature sensor (T1) open or short circuit
K-series (ACiQ-K09W-HP…, TCL-built): Abnormal system operation or lack of refrigerant		FaultDIY checks
E5standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Evaporator coil temperature sensor (T2) open or short circuit
K-series (ACiQ-K09W-HP…, TCL-built): Model configuration or mismatch error		FaultDIY checks
ECstandard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Refrigerant leak detected (low refrigerant charge)
K-series (ACiQ-K09W-HP…, TCL-built): Outdoor module communication fault		FaultDIY checks
F0standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Overload current protection (compressor over-current)
K-series (ACiQ-K09W-HP…, TCL-built): Infrared (remote receiver) sensor fault		VariesDIY checks
EBstandard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Communication error between indoor main board and display board
K-series (ACiQ-K09W-HP…, TCL-built): Main board to LED display communication fault		FaultDIY checks
EFstandard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Intelligent eye (occupancy sensor) module error
K-series (ACiQ-K09W-HP…, TCL-built): Outdoor DC fan motor fault		FaultDIY
F1standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Outdoor ambient temperature sensor (T4) open or short circuit
K-series (ACiQ-K09W-HP…, TCL-built): Power test module fault		FaultDIY checks
F2standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Condenser coil temperature sensor (T3) open or short circuit
K-series (ACiQ-K09W-HP…, TCL-built): Discharge temperature sensor fault protection		VariesDIY checks
F3standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Compressor discharge temperature sensor (TP) open or short circuit
K-series (ACiQ-K09W-HP…, TCL-built): Outdoor coil temperature sensor fault protection		VariesDIY checks
F4standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Outdoor unit EEPROM parameter error
K-series (ACiQ-K09W-HP…, TCL-built): Cooling system gas flow abnormality protection		VariesTechnician
F5standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Outdoor fan speed out of control (outdoor fan motor fault)
K-series (ACiQ-K09W-HP…, TCL-built): PFC protection		VariesDIY checks
P0standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Inverter module (IPM) malfunction
K-series (ACiQ-K09W-HP…, TCL-built): IPM module protection		ProtectionTechnician
P1Over-voltage or under-voltage protectionProtectionDIY checks
P2standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): High temperature protection (compressor top or inverter module)
K-series (ACiQ-K09W-HP…, TCL-built): Over-current protection		ProtectionDIY checks
P3standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Outdoor temperature too low protection (heating lockout)
K-series (ACiQ-K09W-HP…, TCL-built): Other protection (unspecified)		ProtectionDIY
P4standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Inverter compressor drive error
K-series (ACiQ-K09W-HP…, TCL-built): Excessive outdoor discharge temperature		ProtectionTechnician
P5standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Mode conflict (multi-zone)
K-series (ACiQ-K09W-HP…, TCL-built): Cooling mode sub-cooling (anti-freeze) protection		ProtectionDIY
P6standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): Outdoor low pressure protection
K-series (ACiQ-K09W-HP…, TCL-built): Cooling mode overheating protection		ProtectionDIY checks
dFDefrost cycle runningStatusDIY
CLFilter cleaning reminderStatusDIY
APWi-Fi pairing (access point) modeStatusDIY
E6Indoor unit DC fan faultFaultDIY checks
E7Outdoor ambient temperature sensor fault (open or short circuit)FaultDIY checks
E8Outdoor discharge temperature sensor fault (open or short circuit)FaultDIY checks
E9Outdoor IPM or compressor drive faultFaultTechnician
EAOutdoor current sensor test faultFaultTechnician
EEOutdoor EEPROM faultFaultTechnician
EHOutdoor suction temperature sensor fault (open or short circuit)FaultDIY checks
EPOutdoor compressor casing top (overload) faultFaultDIY checks
EUOutdoor voltage sensor faultFaultTechnician
EjOutdoor central coil temperature sensor fault (open or short circuit)FaultDIY checks
EnOutdoor gas pipe temperature sensor fault (open or short circuit)FaultDIY checks
EyOutdoor liquid pipe temperature sensor fault (open or short circuit)FaultDIY checks
P7Heating mode overheating protectionProtectionDIY checks
P8Outdoor over- or under-temperature protectionProtectionDIY
P9Compressor drive abnormal load protectionProtectionTechnician
PAPreset mode conflict or indoor top-flow communication faultProtectionDIY
H1High-pressure switch operatedProtectionDIY checks
H2Low-pressure switch operatedProtectionDIY checks
HdRefrigerant leakage protectionProtectionTechnician
FdRefrigerant leak sensor communication faultProtectionDIY checks
FyRefrigerant deficiency protectionProtectionDIY checks
d4Water-full (drain) protectionProtectionDIY
d5Access control protectionProtectionDIY
F6Compressor phase loss or reversed phase protectionProtectionTechnician
F7IPM module temperature protectionProtectionDIY checks
F8Four-way (reversing) valve abnormality protectionProtectionTechnician
F9Module test circuit temperature faultFaultTechnician
FACompressor phase current (frequency reduction protection)ProtectionDIY
FbCooling or heating overload limit (frequency reduction protection)ProtectionDIY
FCHigh power limit (frequency reduction protection)ProtectionDIY
FEModule or compressor phase current (frequency reduction protection)ProtectionDIY
FFModule temperature (frequency reduction protection)ProtectionDIY
FHDrive limit (frequency reduction protection)ProtectionDIY
FPAnti-condensation (frequency reduction protection)ProtectionDIY
FUAnti-freezing (frequency reduction protection)ProtectionDIY
FjDischarge temperature (frequency reduction protection)ProtectionDIY
FnExternal AC current limit (frequency reduction protection)ProtectionDIY

How ACiQ shows error codes

standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): The code appears on the indoor unit's LED display in place of the set temperature. Some models also blink the indicator lamps in a pattern that matches the code. E codes are faults in the indoor unit or its communication link, F codes are faults on the outdoor side, and P codes are protections: the outdoor unit has stopped itself to prevent damage. EC is the refrigerant leak check.

K-series (ACiQ-K09W-HP…, TCL-built): The indoor display shows the code in place of the set temperature. E codes are faults: something has failed and needs diagnosis. P, H, d and F codes are protections: the system stopped or throttled itself to prevent damage, and many clear on their own once conditions return to normal.

Brands built on the same platform

These brands share a code table with ACiQ because the same factory builds them, so their pages describe the same faults: AirEase, American Standard, Ameristar, Arcoaire, Arctic King, Armstrong Air, Blueridge, Bosch, Bryant, Carrier, Comfortmaker, Concord, Day & Night, Della.

Sources

  • ACiQ Standard Single-Zone Mini Split Service Manual (SZ-Z-HP / W-HP), Quick Maintenance by Error Code
  • ACiQ Mini-Split Air Handler and Condenser Service Manual (MS-SZDM / WHP / KZHP), error code table

Updated September 2026. Manufacturer site: aciq.com