H27

Outdoor Air Temperature Sensor Abnormality

Home Appliance Error Codes Panasonic Split AC

Severity Low It can wait a little, but get it checked soon.
Can you still use it? With care until repaired
Who can fix it? Needs a technician
Typical repair time 30 minutes – 3 hours
Typical cost SAR 80 to 2,500

What it means

This code appears on Panasonic inverter split air conditioners when the fault history is read with the CHECK button. It means the board reads an impossible value from the outdoor air temperature sensor, which points to an open or shorted circuit; this sensor tells the board the outside temperature so it can set compressor and outdoor fan speeds. Depending on the model, the unit stops or keeps running with default settings and reduced efficiency until the fault is repaired. The same number can mean a different fault on other brands.

Models covered: Panasonic residential inverter split air conditioners (wall mounted); the code is read with the CHECK button on the remote control.

Symptoms4

  • A lamp blinks on the indoor unit and cooling stops or weakens.
  • The unit runs and then stops shortly after starting.
  • The unit does not respond properly to changes in the set temperature.
  • The code returns after a restart.

Possible causes5

  • A loose or unplugged outdoor air temperature sensor connector on the board.
  • A failed outdoor air temperature sensor whose resistance no longer matches the manufacturer table.
  • A cut or chafed sensor wire from heat, rubbing or rodents.
  • Sensor damage from direct sun, heat and dust on an exposed outdoor unit.
  • A fault in the sensor input circuit on the board (less common).

How to diagnose5

  1. Switch the unit off at the breaker for a few minutes, restart it and see whether the code returns.
  2. With power off, the technician inspects the sensor at the back of the outdoor unit near the coil, its wire and its connector on the board.
  3. The technician measures the sensor resistance at the current temperature and compares it with the manufacturer table.
  4. The technician checks the wire along its length for breaks or shorts.
  5. If the sensor and wire are good, the technician checks the input circuit on the board.

How to fix5

  1. Restart the unit after a power-off; a one-off glitch may clear.
  2. Reseat the sensor connector and clean its pins.
  3. Repair or replace a damaged sensor wire.
  4. Replace the outdoor air temperature sensor with a part that matches the model.
  5. Repair or replace the board if the input circuit is faulty, then run the unit and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost stays low when reseating the connector or replacing the sensor fixes it, and rises when the board has to be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions

Is H27 serious?

It does not damage the unit by itself, but the unit may stop or run inefficiently, so it should be repaired in the coming days.

Why can the repair reach the upper cost?

The sensor is cheap, but on some models its input is on the outdoor inverter board, which is expensive if it is the faulty part.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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