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Goodman · Heat pump

A3 Outdoor coil temperature sensor fault

High severity Goodman/Amana ComfortNet ASZC/GSZC/DSZC

What the control is telling you

The outdoor coil temperature (OCT) sensor reads open, shorted, disconnected or out of range. This sensor drives defrost, so the heat pump will not run in heating while it is faulted.

Applies to: ComfortNet heat pumps ASZC/GSZC/DSZC (PCBHR104/105 outdoor control)

Likely causes

  • Sensor unplugged or loose at the outdoor control
  • Open or shorted sensor or leads
  • Sensor reading outside the valid range

Test and repair steps

  1. Warning: Kill power to the outdoor unit before touching wiring, the compressor terminals or the control.
  2. Check the OCT sensor plug at the outdoor control and the sensor clip on the coil; repair any damaged leads.
  3. Unplug the sensor and measure resistance roughly 10,000 ohms (plus or minus 10%) around 75-77 F; use the resistance chart for other temperatures.
  4. Replace a sensor that is open, shorted or off the chart, refit it to the coil tube and verify heating and defrost operation.

Models that show this code

24 models in Goodman/Amana ComfortNet ASZC/GSZC/DSZC

ASZC160241ASZC160361ASZC160421ASZC160481ASZC160601ASZC180241ASZC180361ASZC180481ASZC180601DSZC160241DSZC160361DSZC160481DSZC160601DSZC180361DSZC180481DSZC180601GSZC160241GSZC160361GSZC160481GSZC160601GSZC180241GSZC180361GSZC180481GSZC180601

Other codes on the same units

  • 07 Open run circuit
  • 08 No line voltage
  • 09 Low 24 V control voltage
  • A2 Outdoor air temperature sensor fault
  • b0 Indoor blower not running when it should be
  • b9 Indoor airflow lower than requested
  • d0 No shared data on the network
  • d1 Invalid shared data on the network

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Source: Goodman ComfortNet ASXC/GSXC/DSXC, ASZC/GSZC/DSZC, AVPTC/MBVC service manual, Unitary Diagnostic Codes PCBHR104 p.71-77 and PCBHR105 p.78-84; sensor check p.42-43. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.