The "B" on the Shifting Lever
The "B", as I understand it, is a type of engine brake, similar to a Jake Brake on big trucks, without all the ear splitting noise. When I took my 07 TCH in for it's 5000 mile check up, I was told never to use the "B". It could ruin the engine or the transmission or the electric drive motor or some such nonsense. He really didn't seem to know why or at least that is the way it seemed to me; he sounded like he was trying feed me a line. Why would a mechanic say something like that? Why would Toyota make it so readily available if you shouldn't use it? That was one of my favorite features, next to all my other favorite features.
I LOVE MY TCH and I don't want to damage it.
All trucks can use engine
All trucks can use engine braking, whether they're equipped with a "Jake" or not. To clarify...a Jake is an additional braking system, technically called an "engine compression" brake (Jake is a brand name but is what they're commonly called, similar to "Band-Aid" instead of "self-adhesive bandage").
Under normal circumstances, when your foot is off the accelerator or lightly on the brake, the car uses regenerative braking to help slow down either in place of or in conjunction with the physical braking system on the car. When doing this the engine is not engaged so you're saving fuel (as opposed to a non-hybrid, where the engine still uses fuel even though it's not powering the car).
My understanding of the "B" position is that the engine does NOT cut out when you're coasting or braking. Instead, it continues to run and actually helps slow the car down since the engine isn't turning as fast as the car wants (like shifting into a lower gear on a "standard" type vehicle or a big truck).
You would use the "B" position if you were rolling down a long downhill grade rather than constantly riding on the brakes. Constant pressure on the brakes down the side of a mountain would cause them to overheat and eventually fail.