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Goodman Error Code 09: Low 24 V control voltage (AC)

Updated · by Aurora Star Tech Inc.

Goodman error code 09 on a air conditioner means: Low 24 V control voltage. It is also called Goodman diagnostic code 09.

Medium severityAir ConditionerAlso Heat PumpGoodman/Amana ComfortNet ASXC/GSXC/DSXC

Homeowner? What Goodman code 09 means for you

Check, then call Your air conditioner is reporting: Low 24 V control voltage. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Safe things you can check yourself

  • Check the thermostat: right mode (Heat or Cool), set a few degrees past room temperature, and fresh batteries if it uses them.
  • Check both breakers and the outdoor disconnect box beside the outdoor unit; all should be ON.
  • Look at the air filter. If it is grey and clogged, replace it; a blocked filter causes many shutdowns.
  • Keep about 2 feet around the outdoor unit clear of leaves, grass and debris.
  • If you see ice on the pipes or the indoor coil, turn the system off and run only the fan for a few hours, then call a technician.
  • Try one reset: turn the power off for 30 seconds, then back on. If the code comes back, stop resetting and call a technician.

Call (647) 657-2977Book a service call

Licensed technicians serving Vaughan, Toronto and the GTA.

What does Goodman error code 09 mean?

The control sees its 24 V supply below 18 VAC. The unit may still seem to run. Clears when the control voltage goes back above 21 VAC.

Applies to: Communicating 2-stage condensers and heat pumps with the PCBHR104 or PCBHR105 outdoor control (7-segment display): ASXC16/18, GSXC16/18, DSXC16/18, ASZC16/18, GSZC16/18, DSZC16/18

Common causes of Goodman code 09

  • Overloaded transformer
  • Low line voltage
  • Fuse or wiring problem in the 24 V circuit
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

Goodman models that use code 09

Show all 23 models

ASXC160241ASXC160361ASXC160481ASXC160601ASXC180241ASXC180361ASXC180481ASXC180601DSXC160241DSXC160361DSXC160481DSXC160601DSXC180361DSXC180481DSXC180601GSXC160241GSXC160361GSXC160481GSXC160601GSXC180241GSXC180361GSXC180481GSXC180601

Other Goodman AC codes

CodeMeaning
03Short cycling
04Locked rotor
05Open circuit - compressor off over 4 hours
06Open start circuit
07Open run circuit
08No line voltage
b0Indoor blower not running when it should be
b9Indoor airflow lower than requested
Comfort Alert 1Yellow ALERT 1 flash - long run time
Comfort Alert 2Yellow ALERT 2 flashes - system pressure trip
Comfort Alert 3Yellow ALERT 3 flashes - short cycling
Comfort Alert 4Yellow ALERT 4 flashes - locked rotor

All Goodman Air Conditioner error codes →

Goodman code 09: homeowner questions

What does Goodman code 09 mean?

Low 24 V control voltage. The control sees its 24 V supply below 18 VAC. The unit may still seem to run. Clears when the control voltage goes back above 21 VAC.

Is it safe to keep using my air conditioner with code 09?

It depends on the cause. This is often caused by something simple. Try the safe checks below; if the code returns, book a service call before it turns into a no-heat or no-hot-water emergency.

Can I reset Goodman code 09 myself?

You can try one reset (power off for 30 seconds, then on). If Goodman code 09 comes back, the cause is still there and a licensed technician should check it.

Who can fix Goodman code 09 near me?

Aurora Star Tech Inc. repairs Goodman air conditioners in Vaughan, Toronto and across the GTA. Call (647) 657-2977 or book a service call online.

Homeowner help: AC Running But Not Cooling: What to Check

Troubleshooting guides

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. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency HVAC Service

647-657-2977