Hill Hold / Start Assist

[pshawfocus]

I’ve noted that my 2010 450h doesn’t ‘hold’ the car on a very steep hill if I release the brakes, the car roles backwards whilst the yellow warning flashes on the dash.  It’s no real hardship to press the brake with me left foot and balance the car on the gas for a moment, but presumably this means there’s a mechanical / sensor fault somewhere? Or am I talking nonsense and the car doesn’t have this feature installed?  

[Herbie]

Depends which system you have as 'Hill Hold' and 'Hill Start Assist' are two different things.

My 2013 RX450h has Hill Start Assist and requires that you still keep your foot pressed on the brake pedal. If you take your foot off the pedal, after a second or two the HSA will cancel and the car starts to creep forward - this is how it's meant to work, so that the car doesn't roll back in the second or two between releasing the brake pedal and depressing the accelerator. The Owner's Manual also states that this will not work on very steep hills.

Hill Hold, which my car is not equipped with, will do as it says on the tin and hold the car in position on a hill.

[royoftherovers]

I`ve never noticed my 2010 GS450h rolling backwards on any slope.

I do not have any of Hill Start or Assist.

I shall have to try that when I return home.

[Herbie]

36 minutes ago, royoftherovers said:

I`ve never noticed my 2010 GS450h rolling backwards on any slope.

I do not have any of Hill Start or Assist.

I shall have to try that when I return home.

All you do is press the brake pedal down fully and at some point in the travel you'll hear a beep and the TRC light will flash, which means that Hill Start Assist is activated.

I don't know what happens if you have Hill Hold as my car doesn't have it.

[KayCee]

Maybe the Handbrake may need to be adjusted it may be at the limit of its travel

 

[Deathstar]

My IS does this, however, if I put the car in numeral, put the break on, then put it back into drive and release the break she stays put. It caught me out when I had the car new. Just for reference mine is a 2012 IS therefore not a hybrid. I don’t really ever leave the auto box hold me on a hill, that’s what my foot brake is for. 

[pshawfocus]

I’m talking about 20-25% hills where most automatics will role back upon release of the brakes. On less steep hills the ‘creep’ will tend to hold you for that nanosecond before you can push down on the gas and move off. However, on these super steel hills I though my car had assurance that would inhibit it from rolling back as the right foot transitions  from brake to gas pedal. I agree, it’s super bad form to hold a car stationery on a hill with the gas pedal, in a hybrid you’ll typically be wasting Battery power needless and putting the drivetrain through unnecessary stress. I’ll have to have a read of the owner’s manual and see what it says. 

[johnatg]

I just hold the car stationary with my left foot on the brake pedal then release it as I accelerate away. It is the only time I use my left foot on the brake pedal!

[Herbie]

9 hours ago, pshawfocus said:

However, on these super steel hills I though my car had assurance that would inhibit it from rolling back as the right foot transitions  from brake to gas pedal

You still haven't said whether your car has Hill Hold or Hill Start Assist.

My car has the latter and the owners manual states that it does not work on very steep hills.