Lennox Mini Split Error Codes
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Featured codes
- EC07 — EC07 on Lennox mini splits (3WMC/MWMC indoor units) means the outdoor fan speed is op
- EC52 — EC52 on Lennox mini splits means the condenser coil temperature sensor T3 is in open
- EC53 — EC53 on Lennox mini splits means the outdoor ambient temperature sensor T4 is in open
- EC54 — EC54 on Lennox mini splits means the compressor discharge temperature sensor TP is in
- EC56 — EC56 on Lennox mini splits means the evaporator coil outlet temperature sensor (T2B,
- EL01 — EL01 on Lennox mini splits means a communication malfunction between the outdoor unit
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Safe checks with an external tool or supply
These pages list the check you can do from outside the unit, with an optional external tool or maintenance supply. None of them repair an internal fault.
- EC07 — EC07 on Lennox mini splits (3WMC/MWMC indoor units) means the outdoor fan speed is operating outside the norma…
Related troubleshooting guides
Manufacturer manuals
- Lennox Mini-Split Systems Service Manual Corp1816-L7 (E4 sections 4.4/5.5)
- Lennox Mini-Split Systems Service Manual Corp1816-L7 (E5 sections 4.5/5.6, pp 18-21, 43)
- Lennox Mini-Split Systems Service Manual 100030 (official Lennox PDF; 3WMC Table 1 + Sections 5-6 Extended Reference Guide)
- MRCOOL DIY 4th Gen Troubleshooting Manual mc-diy-4-es-tsg-en-01 (same Midea platform; Sections 7.2/7.4/7.5/7.8/7.10-7.13 match the Lennox code family)
- Midea official F2_FULL-DC-R32 troubleshooting sheet (Midea platform used by Lennox 3WMC) - condenser pipe sensor open/short
- MRCOOL DIY 4th Gen Troubleshooting Manual mc-diy-4-es-tsg-en-01 (same Midea platform)
- Midea official E1_FULL-DC-R32 troubleshooting sheet (Midea platform used by Lennox 3WMC) - indoor-outdoor communication error
- MRCOOL DIY 4th Gen Troubleshooting Manual mc-diy-4-es-tsg-en-01 (same Midea platform; PC 08 section)
E codes
- Lennox E1 error code
On most Lennox mini-split code lists E1 is a high-pressure protection trip - dirty/blocked outdoor coil, poor clearance, or an overcharge pushing high… - Lennox E3 error code
On Lennox mini-split code lists E3 means outdoor coil blockage (with possible low refrigerant from a leak) - clean the outdoor coil and reset once; lo… - Lennox E4 error code
E4 on Lennox mini splits is a temperature sensor error: on single-zone units it is the indoor return-air (T1) sensor; on multi-zone outdoor boards it … - Lennox E5 error code
E5 on Lennox mini splits means different things by series: single-zone units show E5 for an indoor coil (T2) sensor error, while multi-zone outdoor bo… - Lennox EC07 error code
EC07 on Lennox mini splits (3WMC/MWMC indoor units) means the outdoor fan speed is operating outside the normal range - the outdoor DC fan ran below a… - Lennox EC51 error code
EC51 on Lennox mini splits (3WMC indoor units) means an outdoor unit EEPROM parameter error - the outdoor control board's main chip is not receiving v… - Lennox EC52 error code
EC52 on Lennox mini splits means the condenser coil temperature sensor T3 is in open circuit or short circuited - the outdoor coil thermistor circuit … - Lennox EC53 error code
EC53 on Lennox mini splits means the outdoor ambient temperature sensor T4 is in open circuit or short circuited - the outdoor air thermistor circuit … - Lennox EC54 error code
EC54 on Lennox mini splits means the compressor discharge temperature sensor TP is in open circuit or short circuited - the discharge thermistor circu… - Lennox EC56 error code
EC56 on Lennox mini splits means the evaporator coil outlet temperature sensor (T2B, multi-zone free-match indoor units) is in open circuit or short c… - Lennox EL01 error code
EL01 on Lennox mini splits means a communication malfunction between the outdoor unit and the indoor unit(s) - the indoor unit received no feedback fr…
F codes
- Lennox F0 error code
F0 on Lennox mini splits (indoor display; outdoor equivalent PC 08) means outdoor compressor current overload sensed - the outdoor current exceeded th… - Lennox F2 error code
F2 on Lennox mini splits (indoor display; outdoor equivalent EC 52) means a faulty outdoor coil temperature sensor T3 - the condenser thermistor circu… - Lennox F3 error code
F3 on Lennox mini splits (indoor display; outdoor equivalent EC 54) means a compressor discharge temperature sensor error - the discharge thermistor (… - Lennox F5 error code
F5 on Lennox mini splits (indoor display; outdoor equivalent EC 07) means an outdoor unit fan speed error - the outdoor fan ran too slow (about 300 RP… - Lennox F6 error code
F6 on Lennox mini splits (indoor display; outdoor equivalent EC 56) means the evaporator coil outlet temperature sensor (T2B) is in open circuit or sh…
P codes
- Lennox P1 error code
P1 on Lennox mini splits means high-pressure protection: the high pressure switch opened (trips at 639 PSI, resets at 464 PSI) because of poor outdoor… - Lennox P2 error code
P2 on Lennox mini splits means low-pressure protection: the low pressure switch opened (trips at 20 PSI, resets at 43 PSI) - typically from low refrig… - Lennox P3 error code
P3 on Lennox mini splits means outdoor unit low-temperature lockout: in heating, the outdoor unit locks out when the temperature stays below -13 F (-2… - Lennox P7 error code
P7 on Lennox mini splits means an outdoor integrated power module (IPM) temperature sensor malfunction - the IPM module's temperature feedback circuit…