Code: PL🔧 Mitsubishi Mini Split

Mitsubishi Mini Split Error Code PL: Abnormal Refrigerant Circuit (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 3 manufacturer & service sources

What the code means

Mitsubishi Electric's outdoor unit service manual for the PUZ-A/PUY-A NKA7 and NHA7 series (OCH636E) defines PL as "Abnormal refrigerant circuit." During Cooling, Dry or Auto Cooling operation, the control flags a failure when both of these are detected for 1 second: the compressor has been running for 30 seconds or more, and the liquid pipe temperature or the condenser/evaporator temperature is 167°F (75°C) or more. In other words, the indoor coil is getting hot when it should be cold, which is what happens when the reversing valve is in the heating position or refrigerant isn't moving through the circuit properly. The manual adds that this error is not cancelled until the power source is reset. On the indoor unit's self-diagnosis, Mitsubishi's indoor service manuals (for example OCH637 for the PKA-A12/18HA7 wall units) show PL as 14 blinks or beeps of the OPERATION INDICATOR, listed as "Abnormality of refrigerant circuit." On the outdoor controller board, PL shows as LED1 (green) blinking 2 times and LED2 (red) blinking 4 times. Mitsubishi Electric Singapore's Mr. Slim error chart uses the same "refrigerant circuit abnormal" name and the same leak, vacuum and refrigerant-circuit checks.

Likely causes

Safe DIY checks

⚠ Before you start

Unplug the appliance or switch off its breaker before opening panels.

  1. Write down the code, the mode the system was in (PL is only detected in cooling, dry or auto cooling) and roughly how long it had been running.
  2. Look at the indoor unit while it's trying to cool. If the fan isn't spinning, tell the technician; Mitsubishi lists a stopped indoor fan as a PL cause.
  3. Check that the indoor unit's air filters are clean and the intake and outlet aren't blocked.
  4. If the system was just installed, moved or had refrigerant work done, call that installer back first. Leaks, disconnected pipes and air in the lines are installation items on Mitsubishi's list.
  5. PL stays on until the power is reset. You can turn the system off at the breaker for a few minutes and restart it in cooling, but if PL comes back, stop restarting it and call a licensed HVAC technician.
  6. Don't try to open the refrigerant circuit or add refrigerant yourself; that work requires an EPA-certified technician.

🛠 When to call a pro

  • Confirm the code on the outdoor controller board (LED1 2 blinks, LED2 4 blinks) or with the A-Control Service Tool (PAC-SK52ST) on connector CNM.
  • Check the 4-way valve and its coil. Mitsubishi's PL table says to be sure to replace the 4-way valve when this error occurs, and its "How to check the parts" section covers the valve and coil tests.
  • Check the refrigerant pipes and flare connections for disconnection or leakage.
  • Check the indoor fan motor and indoor control board if the indoor fan isn't rotating.
  • After recovering the refrigerant, vacuum dry the whole refrigerant circuit. Mitsubishi warns that moisture or air in the circuit can cause abnormally high pressure, so purge the air or replace the refrigerant, then recharge to the nameplate amount.
  • Check the refrigerant circuit for restrictions and verify normal operation before returning the system to service. Under warranty, go through the installing contractor or a Mitsubishi Electric Diamond Contractor.

Parts that commonly fix it

Always match the part number to your exact model.

⚙

Mini split 4-way reversing valve coil or valve (exact part for your outdoor model)

Mitsubishi's PL table says to replace the 4-way valve; match the part number to your outdoor unit's service manual and have a technician install it.

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⚙

Refrigerant leak detector

Leaks and disconnected pipes are on Mitsubishi's PL cause list; a technician uses one to find the leak before vacuuming and recharging.

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⚙

Mini split indoor fan motor (exact part for your indoor model)

A non-rotating indoor fan is a listed PL cause; match the part number to your indoor unit.

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Sources

  1. Mitsubishi Electric outdoor unit service manual OCH636E (PUZ-A/PUY-A12-42 NKA7/NHA7): PL abnormal refrigerant circuit detection (cooling/dry/auto cooling, compressor 30 s, liquid or condenser/evaporator temperature 167°F/75°C, held for 1 s, cleared only by power reset), causes and actions; outdoor board LED1 2 blinks / LED2 4 blinks, via Mitsubishi Tech Info Canada
  2. Mitsubishi Electric PKA-A12HA7/PKA-A18HA7 indoor unit service manual OCH637: self-diagnosis table, PL abnormality of refrigerant circuit = 14 blinks/beeps, via Mitsubishi Tech Info Canada
  3. Mitsubishi Electric Singapore Mr. Slim error code chart (PL refrigerant circuit abnormal, 14 blinks; check pipes for disconnection or leakage, vacuum dry after refrigerant recovery, check refrigerant circuit operation)

Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.