DIY HVAC Tools

Lennox mini split code AP

Wi-Fi pairing (access point) mode.

  • TypeStatus, not a fault
  • SystemDisplay
  • Can I fix it?Usually a homeowner fix
  • Applies toMPA / MPB / MLA indoor unit display

What AP means on a Lennox

The unit's Wi-Fi module is broadcasting its own network so the app can connect and configure it. It shows AP during setup, and sometimes after a power interruption if the module reboots.

On this platform, AP is a status, not a fault: the unit is telling you what it is doing; nothing is wrong.

What to do

You can almost always clear this yourself with the steps below.

  1. Finish pairing in the manufacturer's app, or wait; the unit exits AP mode on its own after several minutes.
  2. To force it out, turn the unit off and on with the remote.

When to call a technician

This is not a fault. No technician is needed unless it will not clear.

Which Lennox units show AP

This page applies to Lennox MPA / MPB / MLA single-zone, MPA / MPB / MLA multi-zone, MCB / MWCB, MWMA / MWMB, MCFA / MCFB and MMDA / MMDB units on the MPA / MPB / MLA indoor unit display. Lennox's own documentation lists AP as "Wi-Fi pairing (access point) mode", the same definition used across the Midea platform (classic codes) it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.

Where Lennox shows this code

MPA / MPB / MLA indoor unit display: 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.

Other Lennox codes

Same part of the system as AP:

dFDefrost cycle runningCLFilter cleaning reminderFPLow-temperature heating hold (46°F freeze-protection mode)FCForced cooling test modeLLRemote or wired controller lockedcFAnti-cold-air (heating warm-up)CPRemote on/off contact open
E0Indoor unit EEPROM parameter error / Outdoor unit EEPROM parameter error (outdoor display)E1Communication error between indoor and outdoor unitsE2Zero-crossing signal detection error / Communication error between the outdoor unit and the indoor units (outdoor display)E3Indoor fan speed out of control (indoor fan motor fault) / Communication error between outdoor main board and IPM board (outdoor display)E4Indoor room temperature sensor (T1) open or short circuit / Outdoor temperature sensor fault: coil (T3), ambient (T4), discharge (T5) or a zone coil outlet (T2B)E5Evaporator coil temperature sensor (T2) open or short circuit / Over-voltage or under-voltage protection (outdoor display)ECRefrigerant leak detected (low refrigerant charge)F0Overload current protection (compressor over-current)

All Lennox error codes

AP on other brands

The same characters do not always mean the same thing. Check the brand on your unit.

Questions people ask

Is AP on a Lennox mini split an error?

No. AP is a status message: wi-Fi pairing (access point) mode. The unit's Wi-Fi module is broadcasting its own network so the app can connect and configure it.

Do I need a technician for Lennox AP?

You can almost always clear this yourself with the steps below. This is not a fault. No technician is needed unless it will not clear.

Sources

  • Lennox Corp1816-L7 Mini-Split Systems Service Manual: Indoor and Outdoor Unit Error Codes (MPA/MPB/MLA, MWMA, MCFA, MMDA), 10/2020
  • Lennox MCB / MWCB Mini-Split Service Manual (error code table 2.1)

Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.