2005 Lexus LS 430 Owners Manual - Page 44

QUICK REFERENCE NOTE: Vehicles with the cruise control: When the cruise control is being used, even if you downshift from "D" or "6" (sixth range) to "5" (fifth range), or "D" or "5" (fifth range) to "4" (fourth range), engine braking will not be enabled because the cruise control is not cancelled. For vehicle speed reduction, see page 329. Vehicles with the dynamic radar/laser cruise control: When the cruise control is being used in the conventional (fixed speed) cruise control mode or in the vehicle−to−vehicle distance control mode, even if you downshift from "D" or "6" (sixth range) to "5" (fifth range) or D", or "5" (fifth range) to "4" (fourth range), engine braking will not be enabled because the cruise control is not cancelled. For vehicle speed reduction, see pages 360 and 345. 5