What It Means
Outdoor coil temperature sensor reading is missing or out of range.
Carrier Air Conditioner
Carrier Air Conditioner Error Code 55
Troubleshooting guide for the Carrier Air Conditioner system fault 55.
Possible Causes
- Faulty outdoor coil temperature sensor.
- Damaged or corroded sensor wiring/connector.
- Sensor unseated or improperly mounted on coil.
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
Outdoor Coil Sensor Fault. Coil sensor not reading or out of range.
All Recorded Causes
Ohm out the outdoor coil temperature sensor and compare to temperature/resistance chart. Check sensor wiring and connector. Verify sensor is properly seated on the coil. Replace sensor if out of spec.
Verify Before Replacing Parts
- Confirm the exact Carrier model family and air conditioners context before acting on a generic code description.
- Confirm filter condition, blower operation, and coil cleanliness before replacing any controls — start by ruling out whether ohm out the outdoor coil temperature sensor and compare to temperature/resistance chart.
- Measure airflow-related readings that match the symptom, such as temperature split or static pressure, and check whether check sensor wiring and connector.
- After the correction, run the system long enough to confirm the air conditioners fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Carrier Air Conditioner diagnostics step-by-step — so you confirm the cause before swapping parts.
