What does E1 mean?
Suction pressure is too low — possible refrigerant undercharge or airflow restriction.
Common causes
- Refrigerant leak
- Restricted filter
- Frozen evaporator coil
- Failed TXV
Diagnostic & testing steps
- 1. Check suction pressure - R-410A should be 100-130 PSI at 70°F return
- 2. Inspect filter and indoor coil
- 3. Check for ice on suction line or indoor coil
- 4. Leak check all refrigerant joints
Tools required
- Manifold gauges
- Electronic leak detector
OEM parts & part numbers
TXV, R-410A Refrigerant
Part numbers: AP13893-3, 59-100879-00
Safety warning
⚠️ EPA 608 certification required for refrigerant service.
Try DiagBuddy AI free — instant 30-second diagnostics for technicians.