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Mitsubishi Electric Air Conditioner P6 Error Code

Freeze or overheat protection. Here is what it means and how to clear it, easiest fix first.

P6
Moderate DIY

The indoor coil got too cold in cooling mode or too hot in heating mode, so the unit stopped to protect itself. Restricted airflow from dirty filters or blocked vents can trigger it; if those are fine, the cause needs a technician to diagnose.

These check codes appear on wired wall controllers, mainly with P-series, Mr. Slim and ducted or ceiling units; wall-mounted M-series units (MSZ) usually report faults by blinking the OPERATION light instead. The meanings here come from Mitsubishi Electric's Mr. Slim code list for Singapore models and its North American wired-controller manual, and they can differ by series and region, so check your manual.

Safety first: unplug the air conditioner (or switch off its breaker) before touching filters, hoses or panels. If you smell burning or gas, or see water near the outlet, stop and call a professional.

How to fix Mitsubishi Electric P6

  1. Clean the filters

    Switch off the breaker, remove and wash the indoor filters, let them dry fully and refit them.

  2. Clear the airflow

    Make sure furniture, curtains or stored items aren't blocking the indoor unit's air intake or outlet, and that supply and return grilles on ducted systems are open.

  3. Reset the power at the breaker

    Switch off the breaker that feeds the air conditioner (some systems have separate breakers for the indoor and outdoor units, so switch off both). Wait about five minutes, switch the power back on and restart the unit to see if the code clears.

When to call a technician

If P6 returns with clean filters and clear airflow, a technician should check the refrigerant charge and fans. Don't open the refrigerant lines.

Parts that commonly cause P6

Order parts by your exact model number so they fit.

Other Mitsubishi Electric air conditioner codes

Frequently asked questions

What does P6 mean on a Mitsubishi Electric air conditioner?

The indoor coil got too cold in cooling mode or too hot in heating mode, so the unit stopped to protect itself. Restricted airflow from dirty filters or blocked vents can trigger it; if those are fine, the cause needs a technician to diagnose.

Can I fix Mitsubishi Electric P6 myself?

Often. The first steps above are safe checks a homeowner can do. If they don't clear P6, the cause is likely a worn part that needs replacing.

What if P6 keeps coming back?

A code that returns after a reset and the checks above usually means a part is wearing out. Note when P6 appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.

Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.

References