What it means
Battery cluster relay sticking detection circuit failure
Cause: After low voltage applied without enabling relay: DO4 input voltage not 20-32V or DI1/2 feedback state is 0; after enabling relay: DO4 input voltage not 20-32V or DI1/2 feedback state is 1.
How to fix it
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