Display shows C2; unit may operate but with incorrect temperature readings.

Safety: Unplug the unit before moving sensors.

Steps:

• Verify actual temperature: Use a separate room thermometer to compare against the unit's displayed temperature.
• Check sensor placement: Ensure the ambient temperature sensor is located in the return air stream, not touching the evaporator coil or discharge air outlet.
• Relocate if needed: Gently reposition the sensor to a more representative location in the intake airflow and secure it with a clip or zip tie.
• Replace sensor: If readings remain inaccurate, replace the ambient sensor. If C2 persists, the main control PCB may have a calibration fault and require replacement.