01 / L1
Low-side fault / low-pressure lockout
This code typically points to
- Low refrigerant charge
- Restricted airflow on indoor coil
- Stuck TXV or metering device
- Compressor operating below low-pressure cutoff
Next checks to confirm
- Check refrigerant charge level
- Inspect indoor coil and filter for restriction
- Verify TXV/metering device operation
- Check low-pressure switch
Escalation
Outdoor unit locks out compressor
Reset behavior
Auto-clears after 30 consecutive normal cycles OR manually cleared by cycling 24 VAC to the outdoor control.
Urgent
Fix now