2008 Toyota Sienna Owners Manual - Page 505
2008 Toyota Sienna Manual
Page 505 highlights
08 SIENNA_U (L/O 0801) CAUTION Never turn off the engine to coast down hills. Your power steering and brake booster will not function without the engine running. Also, the emission control system operates properly only when the engine is running. 464 2008 SIENNA from Aug. '08 Prod. (OM45455U)