E4 01 (FJM Outdoor) — Outdoor unit freezing (compressor stop)

What does E4 01 mean?

The FJM outdoor unit displays E4 01, indicating that freezing conditions have been detected on the outdoor coil, causing the compressor to stop as a safety measure. This can be caused by various factors affecting heat exchange.

• Dirty indoor unit air filters restricting airflow
• Obstructions (ice, debris) on the outdoor unit's coils
• Low refrigerant charge or improper refrigerant flow
• Incorrect pipe length or service port issues

Click steps to track your progress.

1. 1

   Check and clean the air filters in all indoor units to ensure proper airflow.

2. 2

   Inspect the FJM outdoor unit for any ice buildup or obstructions (leaves, debris) that might restrict airflow. Clear any obstructions.

3. 3

   Turn off the unit at the main circuit breaker and allow any ice to melt naturally (if present).

4. 4

   If the problem reoccurs frequently, a qualified technician should check pipe lengths, refrigerant levels, and service ports.