Lennox Error Code Search
Error code search offers information on the cause of the malfunction and the status of your air conditioner by entering the error code.
Disclaimer:
- This page provides a simple explanation concerning content relating to error codes and their possible causes. Please note that the content may slightly differ depending on the model.
2. It is always advised that you consult with an HVAC repair professional before attempting to provide any repairs yourself.
3. Precision Air assumes no responsibility for any accidents or troubles caused in the disassembly or repair of equipment performed according to the information on this page.
Caution:
If molded case circuit breakers or earth leakage circuit breakers have tripped, do not reset the breaker immediately without first checking for any problems with the insulation of equipment.
Resetting breakers without a check of insulation may cause damage to equipment.
Lennox Air Conditioning Codes:
INDOOR UNIT ERROR DISPLAY:
CODE: E0
RESULT: EEPROM parameter error
CODE: E1
RESULT: Indoor/outdoor units communication protection
CODE: E2
RESULT: Zero-crossing signal error
CODE: E3
RESULT: Indoor fan speed out of control
CODE: E5
RESULT: Open or short circuit of outdoor temperature sensor or outdoor unit EEPROM parameter error
CODE: E6
RESULT: Open or short circuit of room or evaporator temperature sensor
CODE: E7
RESULT: Outdoor fan speed out of control
CODE: P0
RESULT: IBM malfunction or IGBT over-strong current protection
CODE: P1
RESULT: Over voltage or too low voltage protection
CODE: P2
RESULT: Temperature protection of compressor top
CODE: P4
RESULT: Inverter compressor drive error
LENNOX SPLIT AC ERROR CODES
F1: Return air temperature sensor open/ short-circuited
P6: Drive board communication error
F2: Evaporator temperature sensor open/ short-circuited
H3: Compressor overheating protection
b5: Indoor unit liquid valve temperature sensor open/short circuited
LP: Indoor and outdoor units unmatched
b7: Indoor gas valve temperature sensor open/ short-circuited
dn: Communication line misconnected or expansion valve error
P7: IPM temperature sensor open/short circuited
E7: Running mode conflict
F3: Outdoor ambient temperature sensor open/ short-circuited
Fo: Pump-down
F4: Outdoor unit condenser mid-tube temperature sensor open/short circuited
C5: Jumper error
F5: Discharge temperature sensor open/ short-circuited
H1: Forced defrosting
E6: Indoor and outdoor communication error
Lc: Compressor start-up failure
PL: DC bus under-voltage protection
E4: High discharge temperature protection
PH: DC bus over-voltage protection
E8: Overload protection
U1: Compressor phase current sensing circuit error
E5: Whole unit over-current protection
HE: Compressor demagnetization protection
P5: Over phase current protection
Hc: PFC protection
H7: Compressor desynchronizing
P8: IPM Temperature Protection
H5: IPM Current protection
L9: Over-power protection
Ld: Compressor phase loss/reversal protection
F0: System charge shortage or blockage protection
F8: Frequency restricted/reduced with whole unit current protection
PU: Capacitor charging error
IPM: Frequency restricted/reduced with
En: Current protection
E1: High pressure protection
F9: Frequency restricted/reduced with high discharge temperature
E3: Low pressure protection
FH: Frequency restricted/reduced with anti-freezing protection
LE: Compressor stalling
F6: Frequency restricted/reduced with overload protection
LF: Over-speeding
EU: Frequency restricted/reduced with IPM temperature protection
PF: Drive board temperature sensor error
E9: Indoor unit full water error
P9: AC contactor protection
E2: Anti-freezing protection
PE: Temperature drift protection
PP: AC input voltage abnormal
Pd: Sensor connection protection
U5: Whole unit current sensing circuit error
U3: DC bus voltage drop error
U7: 4-way valve reversing error
L3: Outdoor fan 1 error protection
H6: Motor stalling
LA: Outdoor fan 2 error protection
U8: PG motor zero-crossing protection
LENNOX AIR CONDITIONER MINI SPLIT ERROR CODES
Lennox MS8 SERIES AC Error Codes
C5: Indoor control jumper is missing
E0: EEPROM failure
EE: EEPROM failure
E1: Communication failure between indoor unit and outdoor unit
E2: Indoor coil freeze protection – All system functions are terminated except indoor fan
E3: Outdoor coil blockage or low refrigerant due to leak
E4: Discharge line temperature protection
E5: Compressor overcurrent protection
E6: Communication failure between indoor unit and outdoor unit
FH: Anti-freezing upper and lower limit range
FO: Indoor coil is gathering refrigerant
F1: Indoor ambient sensor (RT1) open or short-circuited
F2: Indoor coil sensor (RT2) open or short-circuited
F3: Outdoor ambient sensor (RT4)open or short circuit
F4: Outdoor coil sensor (RT3) open or short circuit
F5: Discharge line sensor (RT5) error
F6: Compressor overload limit issue
F8: High current limit issue
F9: Discharge line temperature too high
HC: Power factor correction protection
H1: Defrosting (heat pump only)
H3: Compressor overload protection sensor (CT1.2) malfunction
H4: Compressor high temperature protection
H5: Intelligent Power Module (IPM) module protection
H6: Indoor fan not communicating
LP: Indoor and outdoor unit mismatch
L3: Outdoor DC fan motor malfunction
L9: Power factor protection
PH: High voltage protection
PL: Low voltage protection
Lennox MPA012S4S-1L AC Error Codes
EO: Outdoor EEPROM error
E2: Communication error between outdoor unit and all indoor units
E3: Communication error between outdoor unit main control and IPM control
E4: Temp sensor error
E5: High or Low voltage protection
E8: Outdoor DC fan speed error
F1: Indoor unit #1 coil outlet temp, sensor error
F2: Indoor unit #2 coil outlet temp, sensor error
F3: Indoor unit #3 coil outlet temp, sensor error
F4: Indoor unit #4 coil outlet temp, sensor error
F5: Indoor unit #5 coil outlet temp, sensor error
F6: Indoor unit #6 coil outlet temp, sensor error
P1: High pressure switch open
P2: Low pressure switch open
P3: Outdoor Compressor current overload sensed
P4: High temperature sensed at compressor discharge line
P5: High temperature sensed at outdoor coil
Lpe: Inverter module (IPM) error
Lennox Universal Mini-Split Error Codes
E0: Indoor unit EEPROM error
E1: Communication error between indoor unit and outdoor units
E3: Indoor fan speed error
E4: Indoor Return air temperature sensor error
