Toyota PRIUS V 2016 Quick Reference Manual page 13

Transmission
* The engine brake is the equivalent of downshifting. Shift to "B" when engine
braking is desired (i.e. downhill driving, coasting to a stop, etc.).
Eco Mode
Eco Mode helps achieve low fuel consumption during trips that involve frequent
accelerating and braking.
Refer to the Owner's Manual for more details.
Power Mode
Use when a higher level of response is desired, such as when driving in
mountainous regions.
Refer to the Owner's Manual for more details.
11
Park button
Reverse
Neutral
Drive
Engine brake*
Push
Push