Pre-Charge Relay
WARNING: This page is about a different car, the 2012 Infiniti M35h. However, it is still accessible from the selected car via links, so may be relevant.
The pre-charge relay is contained in the DC/DC converter, and is controlled by HPCM. When supply of high-voltage power is needed, HPCM activates the pre-charge relay and power is supplied via the charging resistor, preventing the sudden application of high-voltage.