F/S Relay
WARNING: This page is about a different car, the 2013 Nissan Leaf. However, it is still accessible from the selected car via links, so may be relevant.
The F/S (fail-safe) relay supplies the driving power for the system main relay inside the Li-ion battery. VCM activates the F/S relay to make the system main relay controllable when the system is set to READY or when the battery is charged.
When VCM detects a malfunction in the EV system and judges that the system main relay must be deactivated, VCM deactivates the F/S relay to shut off the system main relay driving power.