'b' On Gear Selector

[RichieG]

Can anyone tell me what the B on the gear selector is for on an RX400h and when you might use it?

[Boxbrownie]

I had a 400h while my 300 was being TLC'ed last week.....the "B" is the "transmission" braking......similar to slapping a normal auto into a lower gear to give engine braking.

Best regards David

[jbanfie]

Yes,

Normally when in 'D', if you take your foot off the accelerator and free wheel, you do exactly that, the V6 is disengaged from the wheels (don't ask me how), and a gentle braking effect is produced by the front electric motor being used as a generator to charge the Battery. This is a very gentle effect compared with a normal car where engine braking is occuring.

The 'B' setting (not that I have used it much) seems to engage the V6 to provide drag, but also tries to charge the batteries harder to provide additional load on the drive train. When I go down long hills, I gently apply the foot brake, this charges the Battery much more than the 'B' setting in the gearbox.

Cheers

Jon

[ihpj]

IIRC the manual says to use 'B' when descending a steep hill to offer an effect similar of engine braking - yeah pretty much as what everyone else has posted - its just about offering more resistance when driving.

[Mr Pants!]

Is there a limit to how much you can use this?

I put it in B on the motorway and the engine really rev'd when I came off the power, so I clicked it back to D and braked instead. Is there a speed limit you can use it can you damage the car like the effects of putting a manual in 1st gear at 80mph...?

[Boxbrownie]

I would not have thought so.....a bit too easy to slip it in for that.....maybe just a character of the CVT rather than a normal "stepped" auto box.....if you can damage the box that easy then Lexus would deserve a rather large slap for such a design flaw.

Have you not got an owners manual?

Next time I get a loaner I will try it

Best regards David