What It Means
Evaporator coil temperature sensor T2 open or shorted.
Carrier Ductless Mini-Split
Carrier Ductless Mini-Split Error Code E5
Troubleshooting guide for the Carrier Ductless Mini-Split system fault E5.
Possible Causes
- Damaged T2 sensor wiring or loose connector.
- Unseated thermistor not making contact with coil pocket.
- Out-of-calibration or failed T2 thermistor.
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
Evaporator Coil Temperature Sensor T2 Open or Short. The indoor unit detects an open or short circuit on the T2 sensor, which is mounted directly on the evaporator coil to track coil temperature for freeze protection and defrost-related logic — a different function from T1 (code E4), which reads room air temperature for thermostat control rather than coil condition. T2 also sits on the indoor coil, distinguishing it from the outdoor-side sensors T3, T4, and T5 (codes F2, F1, and F3) that monitor condenser coil, outdoor ambient, and compressor discharge temperatures. Because T2 feeds coil-freeze protection, a failed sensor can leave the indoor coil unprotected against icing even if the rest of the system otherwise appears to run normally. The system typically halts or restricts operation while T2 reads out of range rather than continuing to run without coil temperature feedback.
All Recorded Causes
Check T2 sensor wiring and connector at the evaporator coil for damage, corrosion, or a loose connection. Verify the sensor is properly seated in its coil pocket or clip and making good thermal contact — a dislodged sensor can read as open or drift out of range without being electrically failed. Measure sensor resistance and compare it to the manufacturer's temperature/resistance chart. Confirm the fault is T2 (E5) and not T1 (E4), since the two sensors serve different control functions despite similar failure symptoms. Replace the T2 sensor if resistance is out of specification and wiring and connector both test correctly.
Verify Before Replacing Parts
- Confirm the exact Carrier model family and ductless systems context before acting on a generic code description.
- Verify airflow first, then confirm operating pressures and temperature relationship before adjusting charge, since check T2 sensor wiring and connector at the evaporator coil for damage, corrosion, or a lo….
- Look for restrictions, iced coils, or dirty heat-transfer surfaces that can mimic a charge problem, and separately confirm verify the sensor is properly seated in its coil pocket or clip and making good thermal co….
- After the correction, run the system long enough to confirm the ductless systems fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through Carrier Ductless Mini-Split diagnostics step-by-step — so you confirm the cause before swapping parts.
