F3
Pioneer Outdoor Ambient Temperature Sensor Fault

Indoor unit shows F3, often during heating mode

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Open or shorted outdoor ambient sensor, Sensor knocked loose from mounting, Corroded sensor connector, Outdoor PCB sensor input failure

How to Fix / Troubleshooting

Safety first: Turn off power at the outdoor disconnect before opening the outdoor unit panel.

Steps to try:

  • Locate ambient sensor: The outdoor ambient sensor is usually mounted near the air intake grille or on the piping, exposed to outdoor air.
  • Check connection: Ensure the sensor plug is fully seated on the outdoor PCB and free of corrosion.
  • Inspect sensor body: Look for cracks, broken leads, or UV damage. Replace if damaged.
  • Secure mounting: Make sure the sensor is positioned where it can accurately sense outdoor air, not touching hot components.

When to call a pro: If F3 remains after sensor replacement, the outdoor PCB may be at fault.

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Repair Difficulty

Medium 3/5

Required Part

Outdoor Ambient Temperature Sensor (NTC)
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