DIY HVAC Tools

ACiQ mini split error code P2

2 meanings on ACiQ, depending on which series you have. Check the model number on the indoor unit's label.

If yours is a standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built) unit

High temperature protection (compressor top or inverter module).

  • TypeProtection
  • SystemCompressor / inverter
  • Can I fix it?Homeowner checks, then maybe a tech

What P2 means on a ACiQ

Either the thermal protector on top of the compressor opened or the inverter module (IPM) got too hot; different Midea-built models assign P2 to one or the other. Both come down to the outdoor unit not shedding heat. The compressor is being protected from overheating.

On this platform, P2 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.

Common causes

  • Blocked outdoor coil or a failed outdoor fan (in cooling mode).
  • Low refrigerant charge, which makes the compressor run hot.
  • Service valves partly closed, or a kinked or restricted line set.
  • Extremely high outdoor temperatures combined with a dirty coil.
  • A failing compressor.

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

  1. Look at the outdoor unit: clear leaves, cottonwood fluff, snow or ice from the coil and make sure the fan can spin freely and nothing is stacked against the cabinet.
  2. Give the unit 30 to 60 minutes with the power off to cool down, then restart.
  3. Confirm both service valves are fully open.
  4. Inspect the line set for kinks, especially at tight bends near the wall penetration.
  5. Anything inside the refrigerant circuit (sensors are fine, but valves, compressors and leaks are not) needs EPA-certified refrigerant handling. That is a technician job.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

If it returns after the coil is clean and the fan runs, have a technician check the charge and the discharge temperature.

If yours is a K-series (ACiQ-K09W-HP…, TCL-built) unit

Over-current protection.

  • TypeProtection
  • SystemPower supply
  • Can I fix it?Homeowner checks, then maybe a tech

What P2 means on a ACiQ

The outdoor unit's total current exceeded its limit and it shut down.

On this platform, P2 is a protection: the system stopped or throttled itself to prevent damage; many clear on their own once conditions return to normal.

Common causes

  • A dirty outdoor coil or failed fan.
  • Low supply voltage.
  • A refrigerant overcharge.
  • A failing compressor.

How to fix it yourself

Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.

  1. Look at the outdoor unit: clear leaves, cottonwood fluff, snow or ice from the coil and make sure the fan can spin freely and nothing is stacked against the cabinet.
  2. If you own a multimeter and are comfortable using it, measure the supply voltage at the outdoor unit's L1 and L2 terminals with the unit running. A 230 V system should read roughly 208 to 253 VAC.
  3. Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.

Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.

When to call a technician

If the coil is clean and voltage is normal, a technician should check compressor current.

Which ACiQ units show P2

ACiQ sells Standard single-zone (ACiQ-09Z-HP…B / W-HP) and multi-zone and K-series (ACiQ-K09W-HP…, SZDM / WHP / KZHP) units, and this code carries more than one meaning across them: on the standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built), P2 means high temperature protection (compressor top or inverter module); on the K-series (ACiQ-K09W-HP…, TCL-built), P2 means over-current protection. The model number on the indoor unit's label, and which display you are reading, tell you which applies.

Where ACiQ shows this code

standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built): 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.

K-series (ACiQ-K09W-HP…, TCL-built): The indoor display shows the code in place of the set temperature. E codes are faults: something has failed and needs diagnosis. P, H, d and F codes are protections: the system stopped or throttled itself to prevent damage, and many clear on their own once conditions return to normal.

Other ACiQ codes

Same part of the system as P2:

P0Inverter module (IPM) malfunction / IPM module protectionP4Inverter compressor drive error / Excessive outdoor discharge temperatureE9Outdoor IPM or compressor drive faultEPOutdoor compressor casing top (overload) faultP9Compressor drive abnormal load protectionF6Compressor phase loss or reversed phase protectionF7IPM module temperature protection
E0Indoor unit EEPROM parameter error / Communication error between indoor and outdoor unitsE1Communication error between indoor and outdoor units / Indoor room temperature sensor fault (open or short circuit)E2Zero-crossing signal detection error / Indoor fan coil (evaporator) temperature sensor fault (open or short circuit)E3Indoor fan speed out of control (indoor fan motor fault) / Outdoor fan coil (condenser) temperature sensor fault (open or short circuit)E4Indoor room temperature sensor (T1) open or short circuit / Abnormal system operation or lack of refrigerantE5Evaporator coil temperature sensor (T2) open or short circuit / Model configuration or mismatch errorECRefrigerant leak detected (low refrigerant charge) / Outdoor module communication faultF0Overload current protection (compressor over-current) / Infrared (remote receiver) sensor fault

All ACiQ error codes

P2 on other brands

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

  • Pioneer P2 High temperature protection (compressor top or inverter module) / Low pressure protection (outdoor display)
  • Blueridge P2 High temperature protection (compressor top or inverter module)
  • Zone Air P2 Over-current protection
  • Mitsubishi Electric P2 Indoor pipe (liquid) temperature sensor fault (open or short circuit)
  • Trane P2 Over-current protection / Indoor pipe (liquid) temperature sensor fault (open or short circuit)

Questions people ask

Why does P2 have more than one meaning on a ACiQ?

ACiQ sells units built on more than one control platform, and each platform has its own code table. The model number on the indoor unit's label tells you which series you have: standard single-zone and multi-zone (ACiQ-09Z-HP…, Midea-built) units read P2 as high temperature protection (compressor top or inverter module); K-series (ACiQ-K09W-HP…, TCL-built) units read P2 as over-current protection.

Can I reset a ACiQ P2 code myself?

Yes. Turn the system off at the breaker for five minutes, then restart it. If P2 comes back, the fault is real and needs the checks above.

Is it safe to keep running a ACiQ showing P2?

Not repeatedly. A protection code means the unit stopped itself to prevent damage, and resetting it over and over can turn a cheap repair into a compressor failure. Reset once, check the basics, and stop if it returns.

Sources

  • ACiQ Standard Single-Zone Mini Split Service Manual (SZ-Z-HP / W-HP), Quick Maintenance by Error Code
  • ACiQ Mini-Split Air Handler and Condenser Service Manual (MS-SZDM / WHP / KZHP), error code table

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