Error Codes for Carrier Air Conditioners

Carrier air conditioner error codes help both technicians and users identify potential causes of issues in HVAC systems.

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Carrier Error Codes for Indoor Units

Code	Possible Cause
E0	EEPROM parameter error in the indoor unit
E1	Communication failure between indoor and outdoor units
E3	Indoor fan speed out of control
E4	Open circuit or short circuit in the indoor ambient temperature sensor (T1)
E5	Open circuit or short circuit in the evaporator coil temperature sensor (T2)
CE	Refrigerant leak detected
F1	Open circuit or short circuit in the outdoor ambient temperature sensor (T4)
F2	Open circuit or short circuit in the condenser coil temperature sensor (T3)
F3	Open circuit or short circuit in the compressor discharge temperature sensor (T5)
F4	EEPROM parameter error in the outdoor unit
F5	Outdoor fan speed out of control
P0	IPM malfunction or IGBT overcurrent protection
P1	Overvoltage or undervoltage protection
P2	High-temperature protection on the top of the compressor
P4	Inverter compressor drive error
P5	Mode conflict
P6	Compressor voltage protection

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Carrier Error Codes for Outdoor Units

Code	Possible Cause
E0	Malfunction of the outdoor EEPROM
E2	Communication failure between indoor and outdoor units
E3	Communication issues between the IPM board and the outdoor main board
E4	Open circuit or short circuit in the outdoor unit temperature sensor
E5	Voltage protection
E8	Outdoor fan speed malfunction
F1	Defective indoor coil outlet temperature sensor or connector
F2	Defective indoor coil outlet temperature sensor or connector
F3	Defective indoor coil outlet temperature sensor or connector
F4	Defective indoor coil outlet temperature sensor or connector
F5	Defective indoor coil outlet temperature sensor or connector
P1	High-pressure protection
P2	Low-pressure protection
P3	Compressor current protection
P4	Compressor temperature protection
P5	High-temperature condenser protection
P6	IPM module protection

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Other Carrier Error Codes

Code	Possible Cause
DN	Communication error between the main board and EXV
EC	Refrigerant leak detected
EE	Memory card error
EN	Frequency limitation for module circuit protection
EU	Frequency limitation for module temperature protection
FH	Frequency limitation for freeze protection
H1	Defrost cycle or heating oil return
H3	Compressor overheating protection
H5	IPM protection
H7	Compressor speed reduction
HC	PFC protection malfunction
HE	Compressor demagnetization protection
L9	High-voltage compressor protection
LC	Compressor start failure
LD	Compressor phase loss protection
LE	Compressor stalling
LF	Compressor overspeed protection
LP	Mismatch between indoor and outdoor units
PA	Input current protection
PC	Current sensor malfunction
PD	Wiring error protection for the current sensor
PF	Malfunction of the inverter board ambient temperature sensor
PH	High-voltage protection
PL	Low-voltage protection
PP	Abnormal AC input voltage
PU	Capacitor charging malfunction

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