DIY HVAC Tools

Carrier mini split error codes

Carrier's current ductless lineup is built by Midea and uses the Midea code set: the Comfort, Performance and Infinity service manuals (38MHRB, 40MAQ / 38MAQ, 40MPHA / 38MPRA) all reproduce the same E, F and P table. Newer units show the four-character version of the same table (EL 01, PC 04). If your indoor unit shows codes of a different shape, check the model number on its label against your manual.

Covers: Comfort 38MHRB / 40MHHQ, Comfort 38MGR / 40MGQ, Performance 40MAQ / 38MAQ, Infinity 40MPHA / 38MPRA, Carrier multi-zone.

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 Carrier codes

E1Communication error between indoor and outdoor unitsE5Evaporator coil temperature sensor (T2) open or short circuitECRefrigerant leak detected (low refrigerant charge)P4Inverter compressor drive errorF1Outdoor ambient temperature sensor (T4) open or short circuitE4Indoor room temperature sensor (T1) open or short circuitP1Over-voltage or under-voltage protectionF0Overload current protection (compressor over-current)

All Carrier codes

58 codes. Type to filter the list.

CodeMeaningTypeFix
E0Indoor unit EEPROM parameter errorFaultDIY checks
E1Communication error between indoor and outdoor unitsFaultDIY checks
E2Zero-crossing signal detection errorFaultDIY checks
E3Indoor fan speed out of control (indoor fan motor fault)FaultDIY checks
E4Indoor room temperature sensor (T1) open or short circuitFaultDIY checks
E5Evaporator coil temperature sensor (T2) open or short circuitFaultDIY checks
ECRefrigerant leak detected (low refrigerant charge)FaultDIY checks
F0Overload current protection (compressor over-current)ProtectionDIY checks
EBCommunication error between indoor main board and display boardFaultDIY checks
EFIntelligent eye (occupancy sensor) module errorFaultDIY
F1Outdoor ambient temperature sensor (T4) open or short circuitFaultDIY checks
F2Condenser coil temperature sensor (T3) open or short circuitFaultDIY checks
F3Compressor discharge temperature sensor (TP) open or short circuitFaultDIY checks
F4Outdoor unit EEPROM parameter errorFaultTechnician
F5Outdoor fan speed out of control (outdoor fan motor fault)FaultDIY checks
P0Inverter module (IPM) malfunctionProtectionTechnician
P1Over-voltage or under-voltage protectionProtectionDIY checks
P2High temperature protection (compressor top or inverter module)ProtectionDIY checks
P3Outdoor temperature too low protection (heating lockout)ProtectionDIY
P4Inverter compressor drive errorProtectionTechnician
P5Mode conflict (multi-zone)ProtectionDIY
P6Outdoor low pressure protectionProtectionDIY checks
dFDefrost cycle runningStatusDIY
CLFilter cleaning reminderStatusDIY
APWi-Fi pairing (access point) modeStatusDIY
EH 00Indoor unit EEPROM parameter errorFaultDIY checks
EL 01Communication error between indoor and outdoor unitsFaultDIY checks
EH 02Zero-crossing signal detection errorFaultDIY checks
EH 03Indoor fan speed out of controlFaultDIY checks
EH 60Indoor room temperature sensor (T1) open or short circuitFaultDIY checks
EH 61Evaporator coil temperature sensor (T2) open or short circuitFaultDIY checks
EL 0CRefrigerant leak detected (low charge)FaultDIY checks
EH 0AIndoor unit EEPROM parameter errorFaultDIY checks
EH 0bCommunication error between indoor main board and display boardFaultDIY checks
EC 51Outdoor unit EEPROM parameter errorFaultTechnician
EC 52Condenser coil temperature sensor (T3) open or short circuitFaultDIY checks
EC 53Outdoor ambient temperature sensor (T4) open or short circuitFaultDIY checks
EC 54Compressor discharge temperature sensor (TP) open or short circuitFaultDIY checks
EC 56Coil outlet temperature sensor (T2B) open or short circuitFaultDIY checks
EC 07Outdoor fan speed out of controlFaultDIY checks
PC 00Inverter module (IPM) malfunctionProtectionTechnician
PC 01Over-voltage or under-voltage protectionProtectionDIY checks
PC 02Compressor top temperature (overload) protectionProtectionDIY checks
PC 03Pressure protection (high or low pressure switch)ProtectionDIY checks
PC 04Inverter compressor drive errorProtectionTechnician
PC 08Outdoor over-current protectionProtectionDIY checks
PC 0ACondenser high temperature protectionProtectionDIY checks
PC 0FPFC module malfunctionProtectionTechnician
PC 40Communication error between outdoor main board and inverter boardFaultTechnician
PC 43Compressor missing phase (lack of phase) protectionProtectionTechnician
PC 44Compressor zero-speed protectionProtectionTechnician
PC 46Compressor speed out of controlProtectionTechnician
PC 49Compressor over-current (phase current) protectionProtectionTechnician
FPLow-temperature heating hold (46°F freeze-protection mode)StatusDIY
FCForced cooling test modeStatusDIY
LLRemote or wired controller lockedStatusDIY
cFAnti-cold-air (heating warm-up)StatusDIY
CPRemote on/off contact openStatusDIY

How Carrier shows error codes

indoor display, classic two-character codes (38MHRB, 38MGR, 40MAQ): 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.

indoor display, four-character codes (newer units): The display shows a two-letter prefix and a two-character suffix, either together (EH60) or alternating (EH, then 60). Write both parts down; the suffix is what identifies the fault. EH and EL are indoor-side faults, EC is an outdoor-side fault, and PC is an outdoor protection: the unit stopped itself to prevent damage.

Brands built on the same platform

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

Sources

  • Carrier 38MHRB Single Zone Ductless Service Manual SG-38MHRB-01 (Diagnosis and Solution section)
  • Carrier 40MAQ / 38MAQ High-Wall Ductless Service Manual 40MAQ-01SM (Diagnosis and Solution section)
  • Carrier 40MPHA / 38MPRA Infinity High Wall Ductless Service Manual (error code table)

Updated September 2026. Manufacturer site: www.carrier.com/residential/en/us/products/ductless-systems