How to Fix / Troubleshooting

Safety first: Disconnect power at the breaker and outdoor disconnect before cleaning or inspecting components.

Clean condenser coil: Remove debris and gently wash the Trane condenser coil from inside out with low-pressure water. Use a coil cleaner if heavily soiled.
Verify fan speed: Confirm the condenser fan motor runs at full speed and in the correct direction. A weak motor or incorrect replacement can reduce airflow.
Check ambient conditions: Extremely high outdoor temperatures combined with restricted airflow can cause E8. Improve shading and airflow around the unit if possible.
Inspect sensor wiring: Locate the discharge temperature sensor on the compressor discharge line (if accessible). Ensure its wiring harness is intact and firmly connected to the control board.

If E8 recurs, a technician should measure discharge temperature, check refrigerant charge, and test the discharge sensor.

Trane air conditioner shows E8 and may shut down due to abnormal discharge temperature or compressor protection.

Possible Causes