Is error 0x4013 a fault or a warning?

0x4013 is a fault code: the ESS unit enters protection and stops normal operation until it is cleared.

0x4013

Felicity ESS error 0x4013

Failure to connect the main positive circuit relay in the battery cluster high-voltage box

Critical — the ESS unit shuts down and latches a protection fault. Don't keep restarting it — the cause needs checking first.

Energy storage systemCritical

Failure to connect the main positive circuit relay in the battery cluster high-voltage box

Cause: Open-circuit fault detected on main positive relay.

Send faults externally, limit power, request lower high voltage; if command not received within 5s, cut off the main circuit relay.

Source: FLS-ES232LC-S.pdf

What does error 0x4013 mean on a Felicity ESS?: 0x4013 means: Failure to connect the main positive circuit relay in the battery cluster high-voltage box. Open-circuit fault detected on main positive relay.
Is error 0x4013 a fault or a warning?: 0x4013 is a fault code: the ESS unit enters protection and stops normal operation until it is cleared.
How do I clear or fix error 0x4013?: Send faults externally, limit power, request lower high voltage; if command not received within 5s, cut off the main circuit relay.

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.