The Charcoal Cansiter (also known as the EVAP Canister) on your Lexus LS400 is located towards the front passenger side of the engine compartment near the radiator. See the attached Lexus LS400 Fuel System Diagram. The EVAP canister is the round object toward the front passenger side of the drawing.
www.smogtips.com/images/LS400_Fuel_Diagram.jpg
