Help me understand: Engineering Explained Hold issue

[drb3333]

Maybe I don't get it, but his biggest complaint is the loss of Hold mode while on an incline, and there is a very plausible explanation which bugs me.

I am new to this vehicle and seek input from the collective wisdom here.

He said he stopped in to rent skis. He returned to his car which is on a slope in Hold mode. He put his foot on the brake to Start and then shifted into Reverse, but rolled forward.

But, if you slide in behind the wheel and accidentally hit the brake pedal, or if you went to push it in but pumped to get better purchase, doesn't that disengage Hold as normal operation?

What bothers me is such a simple thing negates his whole argument that "it happened all by itself". Far more likely that he pressed twice, I think. Every test he did afterwards was with Hold mode deactivated.

I have watched his video at 4:00 many times and his entire argument hinges on only touching the pedal once. And it saves to your profile...

P.94 of the manual (emphasis mine):

 

[borski]

Maybe I don't get it, but his biggest complaint is the loss of Hold mode while on an incline, and there is a very plausible explanation which bugs me.

I am new to this vehicle and seek input from the collective wisdom here.

He said he stopped in to rent skis. He returned to his car which is on a slope in Hold mode. He put his foot on the brake to Start and then shifted into Reverse, but rolled forward.

But, if you slide in behind the wheel and accidentally hit the brake pedal, or if you went to push it in but pumped to get better purchase, doesn't that disengage Hold as normal operation?

What bothers me is such a simple thing negates his whole argument that "it happened all by itself". Far more likely that he pressed twice, I think. Every test he did afterwards was with Hold mode deactivated.

I have watched his video at 4:00 many times and his entire argument hinges on only touching the pedal once. And it saves to your profile...

P.94 of the manual (emphasis mine):

View attachment 38935​

That may disengage hold, but it doesn’t save it to your profile. Those are separate bullet points.

 

[joec]

Yes. That’s how I read that, too. You can only change the profile setting when the car is in park. And that will save to profile.

The disengaging with the brake is only supposed to be temporary.

 

[drb3333]

Okay, my mistake. I reviewed the video at 5:59 and he only uses profile settings to illustrate the point, and does not say his profile was changed. But my point remains RE plausible explanation...unless I am nuts. Open to correction.

 

[Halodde]

Yes. That’s how I read that, too. You can only change the profile setting when the car is in park. And that will save to profile.

The disengaging with the brake is only supposed to be temporary.

I guess I have to test this. I didn't realize that touching the brake did anything to affect the function of the Hold feature. I thought that once you come to a stop and Hold engages, it stays that way until you press the accelerator pedal.

But I think in his case, this doesn't really apply. He stopped the car, with the Hold feature likely engaging when he came to a stop. But he either put the car in park or the car put itself in park when he opened the driver's door to get out, right?

So, when he got back in and put the car in gear, it would only move (at all) when he released the brake if it had been somehow set to Roll. The direction of movement is bizarre though. It has happened to me once or twice but unrelated to the hold/roll setting. My car moved the wrong way when I pressed the accelerator. It's not without possibility of user error, of course. But I'm pretty sure I had the car in the correct gear.

 

[borski]

Okay, my mistake. I reviewed the video at 5:59 and he only uses profile settings to illustrate the point, and does not say his profile was changed. But my point remains RE plausible explanation...unless I am nuts. Open to correction.

No, it’s a valid question; I think he’s right, in this case, but crazier things have happened before.

There have been many cases (public, but also people I know personally, and more than one) where someone drove straight into a wall (or almost did) because they hit the accelerator instead of the brake. If you remember the Toyota floor mat fiasco, people still think, to this day, that that was Toyota’s fault and floor mats were accelerating cars into other cars. Nope - a very good example of mass hysteria, as people are generally certain they hit the brake and not the accelerator.

In this case, we’ve seen reports that the toggle changed after an update before, so it’s not implausible that happened here.

 

[drb3333]

Toyota case is an excellent comparison. Humans are fallible: I know this personally because I happen to be one.

 

[tonybot]

For my 2024 Pure, the hold setting has occasionally changed to roll on its own. Always in my wife’s secondary profile, and often after a software update. I know it happened at least thrice so far. The first time she called me in a bit of panic, thinking something was wrong with the vehicle, and I walked her through checking the settings and changing them back. The second time, she knew how to fix it herself. Now I make it a point to check after a software update, and I have once fixed it proactively. So we've experienced it 3 times so far, but we didn’t think it was a big deal as it was easily fixable. Not minimizing anyone else’s concern, but just sharing our perspective.

Actually, never reported this to Lucid either.

 

[drb3333]

I guess I have to test this. I didn't realize that touching the brake did anything to affect the function of the Hold feature. I thought that once you come to a stop and Hold engages, it stays that way until you press the accelerator pedal.

Exactly, but new to me.

But I think in his case, this doesn't really apply. He stopped the car, with the Hold feature likely engaging when he came to a stop. But he either put the car in park or the car put itself in park when he opened the driver's door to get out, right?

True, but later when he returns perhaps...

So, when he got back in and put the car in gear, it would only move (at all) when he released the brake if it had been somehow set to Roll. The direction of movement is bizarre though. It has happened to me once or twice but unrelated to the hold/roll setting. My car moved the wrong way when I pressed the accelerator. It's not without possibility of user error, of course. But I'm pretty sure I had the car in the correct gear.

As I read it, things were fine in Park, but if he inadvertently hit the brake twice, then lifting his foot meant Hold was now disengaged and he rolled downhill. I don't think wrong way plays into it, but please check me on this.

I am tall at 6'4" and nearly always squirm when I get in. I do find myself bracing on the left foot pad, for example to settle into the seats.

Without being critical of anyone, I am just considering the option of a guy after renting skis touching the pedal as he got set.

 

[drb3333]

Thanks to all who contributed a response.

Just trying to work out an Occam's Razor scenario.

I was unaware of other similar experiences of profile changes, vs his modification on-the-fly.

Does he ever actually say his profile was changed also? I do not think so--he just toggles it for the camera.

 

[Halodde]

Exactly, but new to me.

True, but later when he returns perhaps...

As I read it, things were fine in Park, but if he inadvertently hit the brake twice, then lifting his foot meant Hold was now disengaged and he rolled downhill. I don't think wrong way plays into it, but please check me on this.

I am tall at 6'4" and nearly always squirm when I get in. I do find myself bracing on the left foot pad, for example to settle into the seats.

Without being critical of anyone, I am just considering the option of a guy after renting skis touching the pedal as he got set.

I just watched that part again. He said he put the car in reverse and when he let go of the brake, he rolled forward/downhill. I don't feel like you should roll forward under any circumstances when the car is in reverse, independent of the hold/roll setting. Maybe I'm off base on that. But, it's not like the car was in neutral and rolled down the hill. If the car is in reverse, it should either stay put on the hill or roll backwards (yes, up the hill- after all the car is supposed to be in reverse). It's not like putting a manual transmission car in reverse when the car could/would roll fwd or downhill as you feathered the clutch to engage the gearing for reversing up the hill.

But, someone can correct me. If you have an automatic transmission ICE vehicle parked on a hill and with the brake pedal depressed, you put the car in the gear that should make it go uphill, would it ever roll downhill when you took your foot off the brake?

Anyway, like I said, I've had the car move the opposite direction from what I expected a couple of times. I never thought much of it because it could have possibly been my fault.

 

[drb3333]

I just watched that part again. He said he put the car in reverse and when he let go of the brake, he rolled forward/downhill. I don't feel like you should roll forward under any circumstances when the car is in reverse, independent of the hold/roll setting. Maybe I'm off base on that. But, it's not like the car was in neutral and rolled down the hill. If the car is in reverse, it should either stay put on the hill or roll backwards (yes, up the hill- after all the car is supposed to be in reverse). It's not like putting a manual transmission car in reverse when the car could/would roll fwd or downhill as you feathered the clutch to engage the gearing for reversing up the hill.

This is a reasonable feature request. But I think you may be describing the intended function of Hold. I am just suggesting that he inadvertently disengaged it from doing its job.

But, someone can correct me. If you have an automatic transmission ICE vehicle parked on a hill and with the brake pedal depressed, you put the car in the gear that should make it go uphill, would it ever roll downhill when you took your foot off the brake?

Yes, the torque converter has limited slipping and will roll you backwards until there is sufficient engine RPM to have an effect.

To tow a car up a hill, the sequence is to hook up, with foot on the brake rev the engine to maybe 2000, then slip off the brake. Done it too many times in my youth pulling my reckless friends out of the ditch.

 

[Halodde]

I had to check this out for myself. I just verified that tapping/touching/pressing the brake pedal once or multiple times does NOT disengage the hold feature in any way regardless of the gear the car is in (fwd or reverse). Once engaged, it will keep you in place until you press the accelerator.

I went so far as to recreate his scenario. Even putting on my seat belt as if I was actually going to drive. When the setting is set to Hold, the car shows 'Hold' when you take it out of park. And it will stay there until you press the accelerator. I fully believe that his setting changed on its own and that's why the car rolled fwd unexpectedly. But I still don't like that it rolled fwd while in reverse.

 

[drb3333]

I had to check this out for myself. I just verified that tapping/touching/pressing the brake pedal once or multiple times does NOT disengage the hold feature in any way regardless of the gear the car is in (fwd or reverse). Once engaged, it will keep you in place until you press the accelerator.

But not Park?

I went so far as to recreate his scenario. Even putting on my seat belt as if I was actually going to drive. When the setting is set to Hold, the car shows 'Hold' when you take it out of park. And it will stay there until you press the accelerator. I fully believe that his setting changed on its own and that's why the car rolled fwd unexpectedly. But I still don't like that it rolled fwd while in reverse.

Thanks for checking this out! But the original owners manual in the first post says the operation is in Park. So, get in Park with Hold, press and release the brake, and see if Hold is still in effect, perhaps.

 

[borski]

Yes, the torque converter has limited slipping and will roll you backwards until there is sufficient engine RPM to have an effect.

And if the car is 5500 lbs, that's a lot of potential energy to overcome.

 

[Pragmatic]

I just watched that part again. He said he put the car in reverse and when he let go of the brake, he rolled forward/downhill. I don't feel like you should roll forward under any circumstances when the car is in reverse, independent of the hold/roll setting. Maybe I'm off base on that. But, it's not like the car was in neutral and rolled down the hill. If the car is in reverse, it should either stay put on the hill or roll backwards (yes, up the hill- after all the car is supposed to be in reverse). It's not like putting a manual transmission car in reverse when the car could/would roll fwd or downhill as you feathered the clutch to engage the gearing for reversing up the hill.

But, someone can correct me. If you have an automatic transmission ICE vehicle parked on a hill and with the brake pedal depressed, you put the car in the gear that should make it go uphill, would it ever roll downhill when you took your foot off the brake?

Well I disagree. I leave mine in roll specifically to allow movement opposite the gear selected. During parking maneuvers on grades I always let the car roll opposite to the direction selected.
For example parking on a grade I will reverse into the spot, release the accelerator, let the car roll forward, pulling the nose in. Finally I'll press the accelerator to back to my final position.
Also my experience automatics (limited in that I've only owned one) is on moderate grades they will roll opposite the gear selected unless fed some throttle.
Either way choice is good, but the car should not change a drive setting.

 

[joec]

I had the car spontaneously change its hold setting once. No idea how it happened. Once I figured it out, I changed it back. Never happened again.

So it does happen. Legitimate software bug. Maybe some combination of tapping brakes triggers it? Maybe something else triggers it? Who knows?

I do agree with the OG poster here that even if this did happen to the creator of the video, the "multiple" times it happened to him were all just the result of him now being in roll instead of hold. In other words, the bug happened to him once. His explanation makes it sound like there was a consistent bug happening over and over again. But the car itself was doing what is should have done, given it was now in roll mode. He just didn't know yet that it was in roll mode.

At least that's how I saw it?

 

[Halodde]

But not Park?

Thanks for checking this out! But the original owners manual in the first post says the operation is in Park. So, get in Park with Hold, press and release the brake, and see if Hold is still in effect, perhaps.

I'm confused by that because I don't know that Hold applies in Park. The car does not display Hold and Park at the same time on the center screen. Once you put the car in a gear, it shows the Hold symbol next to that display. But Park overrides either drive setting.

 

[drb3333]

I'm confused by that because I don't know that Hold applies in Park. The car does not display Hold and Park at the same time on the center screen. Once you put the car in a gear, it shows the Hold symbol next to that display. But Park overrides either drive setting.

First of all, thanks for using some of your holiday time to think about this. My car is in the shop so I cannot do the same.

I am just pointing out what I interpret the manual as saying that when in Park, pressing and releasing the brake pedal will exit Hold mode. So if you then shift to Drive or Reverse without the accelerator pressed, the car may roll. But maybe I am misunderstanding.

I really wish I could personally test this out without wasting your and everyone else's time. But thank you!

 

[borski]

First of all, thanks for using some of your holiday time to think about this. My car is in the shop so I cannot do the same.

I am just pointing out what I interpret the manual as saying that when in Park, pressing and releasing the brake pedal will exit Hold mode. So if you then shift to Drive or Reverse without the accelerator pressed, the car may roll. But maybe I am misunderstanding.

I really wish I could personally test this out without wasting your and everyone else's time. But thank you!

I just tried this. The manual is wrong.

If you open the door, it goes into Park. Once it is in park, the brake and accelerator pedal do nothing.

If I am in hold, depressing and releasing the brake also does nothing.