For Component Replacement
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.
Turn ignition switch to LOCK position. Remove auxiliary battery access panel located in trunk. Disconnect and shield negative battery cable. If working near Toyota Hybrid System (THS) wiring or components, disable THS. See DISABLING & ACTIVATING TOYOTA HYBRID SYSTEM (THS) . Wait at least 90 seconds before starting any work on vehicle.