Lennox Mini Split P2 Error Code

Updated 2026-08-30 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-30

Check your model first

  • Lennox outdoor (Service Manual 100030, Section 5.9, P2/PC 31)
  • Lennox indoor (100030 Section 6.18, P2/PC 02)
  • Midea-built platform (MRCOOL PC 02/PC 03; Midea P6 low-pressure sheet)

Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.

Quick answer

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 refrigerant, a closed service valve, too-cold outdoor conditions, or poor indoor airflow in cooling. Some indoor displays use P2 for the PC 02 compressor-top over-temperature protection instead. One power cycle; refrigerant, pressure-switch, and gauge work is technician-only.

Severity: high · DIY difficulty: easy

Safety

Stop at the breaker power-cycle and any plug-accessible checks (filters, remote settings, visible wiring). The outdoor unit's capacitor holds a lethal charge and the refrigerant circuit is both pressurized and (on R-32 units) flammable — opening panels or servicing the sealed system is licensed-technician work (EPA 608).

What P2 means

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 refrigerant, a closed service valve, too-cold outdoor conditions, or poor indoor airflow in cooling. Some indoor displays use P2 for the PC 02 compressor-top over-temperature protection instead. One power cycle; refrigerant, pressure-switch, and gauge work is technician-only.

Code meaning varies by series

  • Lennox outdoor (Service Manual 100030, Section 5.9, P2/PC 31): P2 = low pressure switch open; trips at 20 PSI, resets at 43 PSI; static pressure ~188 PSI
  • Lennox indoor (100030 Section 6.18, P2/PC 02): P2 (indoor display form) = compressor top high temperature protection (OLP)
  • Midea-built platform (MRCOOL PC 02/PC 03; Midea P6 low-pressure sheet): Platform low-pressure / compressor-top over-temperature protection family - same remediation

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

  1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

    Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

    Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

  2. 2. Fault persists after a clean reset occasional pro only

    Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

    Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.

Related codes

Cross-references for the same fault family, by brand:

Lennox P1 · Lennox P3 · Lennox EC54 · Lennox F3 · Lennox F0 · Lennox EC07

Commonly searched as: "lennox p2" · "lennox error code p2" · "lennox air conditioner p2"

Sources

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