That's definitely not how I interpreted that message you posted...what I read was someone who didn't have the answer and was being polite about the extent of their knowledge.
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When, specifically, are hills held when hill holder is ON?
- Thread starter scottm
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- Driving Dynamics Model S
That's definitely not how I interpreted that message you posted...what I read was someone who didn't have the answer and was being polite about the extent of their knowledge.
My take is that if it worked based on pedal pressure, that information would be available to Tesla customer service as well as owners via the Owners Guide. Nowhere is it said that you have to do anything but apply the break normally. If it required added pressure, then Tesla would say so. Based upon my own experience, break pedal pressure does not engage the feature. It is entirely dependent upon the grade of the hill. You can test this out quite easily. If break pedal pressure activates the feature, you should be able to activate it on demand. By the same token, on a 4% or higher grade the feature should enable as soon as you come to a stop and without applying any undue pressure to the break pedal. This can be easily and quickly tested out in the field, and based upon my tests and experience, it works exactly as Tesla has described.
Some other vehicles may use break pedal pressure and I think that's where the confusion may have occurred for some owners. The fact that it activates on grades 4% and higher means that it doesn't function when on a hill less than 4% grade, and the variability of how this works may have led some owners to equate its operation with brake pedal pressure because, coincidentally, that's what they were doing at the time.
I can get hill hold on my driveway, which is under 1% grade. I've never seen an explanation from Tesla on how it actually works, but if that 4% number actually comes from them, either they have a calibration problem (which would explain a lot) or there are more variables involved.
Hi
i went through this back when the feature was first released. I can't find the original email from Tesla but my initial information was later corrected and I got the following (excerpt) from a reliable source.
Apparently the system will only hold the hydraulic pressure applied to it through the brake pedal, through use of the ABS / ESP module. This makes a little more sense in terms of pedal pressure having an affect on the performance of this feature. If you only slightly apply the pedal at full stop, chances are it might not be enough pressure to hold the weight of the vehicle. I suppose drivers who use the creep feature may naturally apply more pedal pressure to stop the vehicle.
The only thing I've found that works reliably (besides being on a very steep hill) is if I release the brake and it starts to roll, I reapply the brakes aggressively and thereafter the car holds.
i went through this back when the feature was first released. I can't find the original email from Tesla but my initial information was later corrected and I got the following (excerpt) from a reliable source.
Apparently the system will only hold the hydraulic pressure applied to it through the brake pedal, through use of the ABS / ESP module. This makes a little more sense in terms of pedal pressure having an affect on the performance of this feature. If you only slightly apply the pedal at full stop, chances are it might not be enough pressure to hold the weight of the vehicle. I suppose drivers who use the creep feature may naturally apply more pedal pressure to stop the vehicle.
The only thing I've found that works reliably (besides being on a very steep hill) is if I release the brake and it starts to roll, I reapply the brakes aggressively and thereafter the car holds.
Franko30
Member
That might be why I never had the feature not working: I use the creep feature. And with my car, too, it works at very shallow inclines.
Frank
Frank
I also imagine that with creep on, a very minor uphill slope is probably less obvious as the creep might overcome the backwards motion.
Franko30
Member
Yes, that's true, but the hill assist feature actually engages on "hills" with less tgan 4 % incline.
Frank
Frank
I wish this worked like my wife's MBZ E350. The brake has a "HOLD" function. Just press a little harder on the brake pedal and hold there for a couple of seconds. Brakes stay on until the accelerator pedal is pushed. No issues about % slope or anything. Just works when you want it.
Johann Koeber
Happy Owner
Yes that is what I want.
More generally, I am annoyed by the unpredictable behaviour of the break assist. How do I know whether it has 4 % slope? The car will move backwards even if the slope is only 2 %, possibly creating a dangerous situation.
So foremost for me is a predictable functioning of the brake. I would not mind, if it would be engaged every time the car wants to start moving in the 'wrong' direction. This would be consistent and user friendly. It could then disengage as soon as the car wants to move in the 'right' direktion, be it because of creep or because I am pressing the accelerator.
Sounds easy to implement to me. But you never know.
Thanks everyone and especially Amp'd for digging in and even bothering to bug Tesla. The answer is %grade.
Makes sense it's grade related. 4% grade is not much. That's a 4 inch rise over about 8 feet, and is what a concrete slab of a driveway would have to allow water run-off.
But like others have said, there probably should be no grade dependency on the feature working. And this gets away from having to use logic if the car is in D or R and facing uphill or downhill.
The only driving (car in gear) conditions should be "car is at rest and brake pedal is applied". These two conditions becoming TRUE should fire the hill assist trigger to hold braking. Conditions could be arrived at in either order while car is in gear: First the brake is applied then car rolls to stop, then hill hold. Or, the car rolls to a stop, then the brake is applied, then hill hold. Hill hold is held, until go pedal is pressed. So each time the go pedal is pressed the hill hold is cleared. Changing the gear while car being hill held would not cause it to release.
Easy peasy. Whole lot less code, and no trigonometry required.
Tesla: take one of your Apple new hires and have them clean up this piece!
Makes sense it's grade related. 4% grade is not much. That's a 4 inch rise over about 8 feet, and is what a concrete slab of a driveway would have to allow water run-off.
But like others have said, there probably should be no grade dependency on the feature working. And this gets away from having to use logic if the car is in D or R and facing uphill or downhill.
The only driving (car in gear) conditions should be "car is at rest and brake pedal is applied". These two conditions becoming TRUE should fire the hill assist trigger to hold braking. Conditions could be arrived at in either order while car is in gear: First the brake is applied then car rolls to stop, then hill hold. Or, the car rolls to a stop, then the brake is applied, then hill hold. Hill hold is held, until go pedal is pressed. So each time the go pedal is pressed the hill hold is cleared. Changing the gear while car being hill held would not cause it to release.
Easy peasy. Whole lot less code, and no trigonometry required.
Tesla: take one of your Apple new hires and have them clean up this piece!
billarnett
Member
But what if you WANT the car to roll downhill a little, say parallel parking on an uphill? You don't want to shift into R and press the accelerator! Too much opportunity for a major screw up
Nah, the best hill hold mechanism is your left foot.
Nah, the best hill hold mechanism is your left foot.
mknox
Well-Known Member
Neutral? I assume they wouldn't implement hill hold in neutral 'cause that kinda defeats the purpose of neutral.
