Circuit Description - DTC P3125 - Information Code 308: Notes
WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.
If the HV ECU detects the collision signal from the AIRBAG or inverter, the HV ECU recognizes it as the destruction of the vehicle and then shuts down the high voltage system to ensure safety.