What It Means
Secondary 24VAC control voltage is below 18 VAC limit.
Goodman All Systems
Goodman Error Code 09
Troubleshooting guide for the Goodman system fault 09.
Possible Causes
- Secondary control voltage below 18 VAC.
- Overloaded 24V control transformer.
- Low incoming line voltage to transformer.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Control detects secondary voltage less than 18 VAC./Transformer overloaded./Low line voltage.
All Recorded Causes
Verify Before Replacing Parts
- Confirm the exact Goodman model family and default context before acting on a generic code description.
- Verify current draw, overload status, and control signal before condemning the compressor or drive, given that the most likely cause listed above.
- Look for upstream conditions such as airflow or charge issues that may be pushing the compressor into protection, and check the next candidate on the list.
- After the correction, run the system long enough to confirm the default fault does not return under normal load.
Not sure which system this Goodman code is on?
ACLogics has guided diagnostics for 20 Goodman fault codes and asks the right questions to narrow it down.
