What It Means
Compressor discharge line temperature protection threshold reached.
York All Systems
York Error Code P4
Troubleshooting guide for the York system fault P4.
Possible Causes
- Low refrigerant charge causing high discharge superheat.
- Liquid line restriction or expansion valve failure.
- Failing compressor internal valves or high compression ratio.
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
Discharge Pipe Temp. Protection.
All Recorded Causes
Verify Before Replacing Parts
- Confirm the exact York model family and default context before acting on a generic code description.
- Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since the most likely cause listed above.
- Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm 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 York code is on?
ACLogics has guided diagnostics for 60 York fault codes and asks the right questions to narrow it down.
