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When, specifically, are hills held when hill holder is ON?

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scottm

Legacy account
Jun 13, 2014
3,070
2,387
Canada
I guess hill hold brakes came along since 6.1. I have MS Classic (Sept.14) with no auto-pilot gear.

I have it turned on. And I've witnessed it working, so I've seen it do its job.

Yet, in similar stopped situations, I've also witnessed no holding after taking my foot off the brake.
The car will roll forward or reverse as soon as brake pedal lifted.
It's been like this ever since I've had the car... and same through every software release since.

Not sure if this is by design or something else?

Are there a specific set of criteria under certain conditions that must be met for a hill hold happen?
I've tried experimentation looking for a repeatable and predictable case:
Degree of slope. How hard I press on the pedal at the stop sign, before release.
When I apply brake (late or early) in the slope of regen doing most of the work.
How hard or fast I initiate braking after getting off the accel pedal.
Putting the brakes on only after regen has practically stopped the car.
Repeated application of brakes at the stop sign.
The amount of time at rest with pedal pressed.
blah blah blah

Can't find a pattern.

Are there situations where we can expect hill hold not to happen (by design), even when switched ON?

Not that this matters hugely... it's just nice to know if we have a "sometimes" feature, when turned on.
I'd expect an ON feature to always be the same and react the same... right now it seems the car is just moody.

FYI, I have Creep OFF, always keep it off.
 
I have noticed a similar pattern. However, I think how long the brake is pressed for has something to do with it. In my own experiments, how forceful the brake is pressed seems to also play a part in it.
I think it works about 80% of the time when I am on an offramp at the lights at the top of the slope.
(I also have creep off).
 
I wonder if slope degree is the major factor?

At a given stop, I've been able to repeatedly press brake, release, it holds then lets go, press brake again, release, it holds then lets go, .... many times in a row. With varying pressures, time waited between releases.

My wife gives me these what the heck are you doing looks when I do experiments like this. Usually followed by "don't! it makes me car sick".
 
For me, it's hit and miss. My driveway has a barely perceptible slope, and Hill Hold almost always works there, yet I've been at intersections with much greater slopes and have had it not work.

I've found that if the car rolls back and I "jab" the brake jerking the car to a stop, the Hill Hold will engage. If I gently apply the brakes at the same spot, it will not engage.
 
Tesla's hill assist should extend to all situations when the car is stopped, even on flat terrain. The "hill assist" should hold the car indefinitely until you press on the accelerator pedal. This way it will always work.

Yes, that is the way I thought it would be when it was announced. However, it is not like that (at least not for me and 2 others so far).
Is there any one that has Hill Assist working all the time like AmpedRealtor described?
 
Has anyone looked at the manual to see if it explains how to activate the hill assist? In my Prius it activates only with a fairly hard press of the brake.

So release notes said:
"When Model S is on a hill,Hill Start Assist will automatically hold the car for one second when the brake pedal is released."

So I guess the inconsistency is when Model S detects a hill?
 
Is hill assist now a toggleable option? When it was introduced in 5.x? it was always on. Based on angle of incline. Subtle hills don't seem to trigger it. Holds for 1 second after releasing brake.

EDIT: I see ItsNotAboutTheMoney beat me to it.
 
Tesla's hill assist should extend to all situations when the car is stopped, even on flat terrain. The "hill assist" should hold the car indefinitely until you press on the accelerator pedal. This way it will always work.

Except that that way you'd have less control over a maneuver on a hill. Personally, I think that the 1 second delay is a bit short. I think the Prius does 2 seconds.
 
mibaro2 said:
Originally Posted by AmpedRealtor

Tesla's hill assist should extend to all situations when the car is stopped, even on flat terrain. The "hill assist" should hold the car indefinitely until you press on the accelerator pedal. This way it will always work.



Yes, that is the way I thought it would be when it was announced. However, it is not like that (at least not for me and 2 others so far).

Is there any one that has Hill Assist working all the time like AmpedRealtor described?

Hi,

It always works for me in my Model S Signature (Germany, 09/2013) ever since Tesla introduced it way before 6.1

Sent from my phone using Forum Fiend.
 
Except that that way you'd have less control over a maneuver on a hill. Personally, I think that the 1 second delay is a bit short. I think the Prius does 2 seconds.

How so? In order for this assist to work, you have to use your brake and be at a complete stop. You are not doing any maneuvering when you are stopped, and to go forward you have to press the pedal in all circumstances anyway. Hill assist is transparent to the driver and should have no impact on maneuverability as far as I can tell.
 
Well, a few of us are here to say, no, it doesn't work on every terrain. We have each found examples where she no work.

And I am wondering under what conditions it decides (or forgets to decide) that it is to work.


...p.s. you can edit posts but maybe you have to be a member for so long or have some number of posts under your belt in order to do so.

- - - Updated - - -

I should clarify, there is no ON switch for the feature it is just on all the time, is my understanding.

I think the feature was announced to me when the car upgraded to 6.1 which was the second day of ownership.

Not sure if it was a selectable feature before that on earlier software versions.

- - - Updated - - -

I guess what I am asking for is for somebody find a spot where hill hold works sometimes, and sometimes not, and they can figure out what driving dynamic it takes to induce it to happen.
 
I guess what I am asking for is for somebody find a spot where hill hold works sometimes, and sometimes not, and they can figure out what driving dynamic it takes to induce it to happen.

As far as I can tell, it's just the grade of the road coupled with the rolling resistance of the road for a given set of tires. If the grade is steep enough it works every time; if it's not, it doesn't. I assume this would be more of a problem if creep mode was turned on, but I've never tested. I suppose there is a "perfect" grade that could sometimes work and sometimes not depending upon the exact placement of the tires relative to the stop line and lane centre.