Fuel System Pressure Release
WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
ALWAYS release fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components.
For procedure, see FUEL SYSTEM in REMOVAL & INSTALLATION - EXCEPT GX470 article.