Car rolls backwards uphill in D

JamieGeek

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I understand that, but to go UP a hill, the car has to power the motors. The sections of the manual you have cited are referring to 1PD not being able to slow the car all the way to a stop when on a steep grade. That is not what is happening here.

Today, coming out of a parking garage near a baseball stadium, I was waiting to make a left turn onto the main street. The car was in D on 1PD mode, and I was stopped. The car was pointing down a maybe 15% grade on an apron. I inched forward to attempt the left turn, but traffic prevented it, so I lifted off the throttle again. The car stopped, AND THEN ROLLED BACKWARDS, UP the 15% graded apron as if it were in reverse. That requires active power -- gravity would have put me onto the street in front of my current position.

It is very fortunate that the drove of fans coming out of the baseball game saw the car rolling backward and jumped out of the way while I jammed on the brake. I don't want to overdramaticize this though, as the car moved no more than maybe 3 feet, and was at very low speed (< maybe 2 mph.)

So you see, this is not a case where the Mach-e was unable to stop. Instead, this is a case where the car actively powered backwards while in drive.
Right I had noted that.

This is very odd and something that my car to date hasn't done and I drive exclusively in 1-P mode.
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After reading this thread I recall somewhere in the owners that there is a level sensor in the vehicle associated with the anti theft system to warn of jacking the car up but it may also be related to the drive system to help hold the vehicle on a grade. Sounds like something that needs to be brought to the attention of Ford and your dealer.
 

ARK

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@dml105 maybe change the title to "car rolls backward UPHILL when in D on a downhill slope"; people aren't reading carefully and are assuming the auto hold is off and the car is rolling backward DOWNhill.
I just understood what OP is saying, I think the word ‘rolling’ caused confusion, at least to me rolling implies the car is moving without power due to its momentum or gravity. But OP seems to mean the vehicle is applying power to reverse itself up a hill while in drive and facing downhill.
 

ARK

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I understand that, but to go UP a hill, the car has to power the motors. The sections of the manual you have cited are referring to 1PD not being able to slow the car all the way to a stop when on a steep grade. That is not what is happening here.

Today, coming out of a parking garage near a baseball stadium, I was waiting to make a left turn onto the main street. The car was in D on 1PD mode, and I was stopped. The car was pointing down a maybe 15% grade on an apron. I inched forward to attempt the left turn, but traffic prevented it, so I lifted off the throttle again. The car stopped, AND THEN ROLLED BACKWARDS, UP the 15% graded apron as if it were in reverse. That requires active power -- gravity would have put me onto the street in front of my current position.

It is very fortunate that the drove of fans coming out of the baseball game saw the car rolling backward and jumped out of the way while I jammed on the brake. I don't want to overdramaticize this though, as the car moved no more than maybe 3 feet, and was at very low speed (< maybe 2 mph.)

So you see, this is not a case where the Mach-e was unable to stop. Instead, this is a case where the car actively powered backwards while in drive.
This is a big deal, the vehicle applied power to reverse itself when you were in drive. Particularly since you can replicate it, I think you should report it to your dealer.
 

OlyPen

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What drive mode (I know the drive modes alter 1PD)? And have you tried to replicate it with Auto Hold on?
 


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dml105

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OK. Just did some more investigating. The place I know where it happens, my kid's day care parking lot, is vacant at night, so I drove through the spot a bunch of times just now.

I think it's a transition from downhill to flat that is causing the problem. The parking lot has a downward incline towards a sidewalk, the sidewalk is level, and then the apron goes downhill again to the street. If I creep up to the sidewalk (going downhill) and then release the pedal so that the front tires just cross into the sidewalk (level), it rolls back up the hill. Not EVERY time, but about half the times I tried just now. Normally, when I feel it rolling back, I jam the brakes because it's pretty unsettling, but tonight, I decided to see what happens. It eventually did stop and the brakes engaged, but only maybe between 1 and 2 feet from the farthest forward I had gotten.

So, I think the car is thinking "I'm going down a hill towards a stop, I need to apply X force backwards to counter the downhill as I slow to a stop." But then hitting the level just before stopping, the car needs less than that force to actually stop, thus stopping sooner, and with excess pushing it backwards back up the hill.

I'm still going to engage @Ford Motor Company over this. That's a scary situation in cities where pedestrians walk close behind cars when they pass the sidewalk.

@OlyPen: I'm using 1PD in engage mode. I haven't tried other drive modes, or auto hold. I'll see if that makes any difference next time I go out.
 

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@OlyPen: I'm using 1PD in engage mode. I haven't tried other drive modes, or auto hold. I'll see if that makes any difference next time I go out.
I get my MME next week, so I'm curious about reproducing this. I have a 2019 Leaf and it does some interesting things in 1PD that required a learning curve, especially when using the brake LOL (when you apply the brake, the car reverts out of 1PD and goes into coasting with the brake applied and when you let off the brake it strongly reverts back to 1PD and stops quicker as you let off the brake). Once I figured out what was happening, it was fairly easy to compensate for it so I didn't fly through the windshield. ?

And I'm curious if Auto Hold corrects the issue.
 

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I bet auto hold is makes the car knock off its antics. I’m an OPD guy myself but have had auto hold on since I picked it up. With all the other assists on, why not auto hold as well?
 

67 Stang Convertible

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I am still a few weeks away from ownership. However when I took one for the day from my dealer I did notice the car would aggressively brake at the end of my driveway as it's approximately a 20 degree downhill slope. I believe it thinks I'm running into a wall; just as my Kia chimes go nuts when I go down the driveway. But your issue seems different that it actually switches gear. Just wondering if the "crash detection" has anything to do with it.

Also wondering from current owners is the car will "learn" that this is the end of my driveway over time?
 

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This still makes no sense. The rear collision detection should kick in if there are any obstacles (such as pedestrians) behind you and slam on the brakes, no matter what the ghost in the machine is trying to do.
 
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dml105

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I bet auto hold is makes the car knock off its antics. I’m an OPD guy myself but have had auto hold on since I picked it up. With all the other assists on, why not auto hold as well?
I tried auto hold this morning. I only gave it one try since there were people around, but it did seem to grab the car when it stopped on the level sidewalk instead of rolling back up the hill. More testing required.
As to why no auto hold, I had turned it off when I was using 2PD cuz I just didn’t love it. And I had never turned it back on when I switched to primarily using 1PD, because 1PD pretty much does that automatically.
 

JamieGeek

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I tried auto hold this morning. I only gave it one try since there were people around, but it did seem to grab the car when it stopped on the level sidewalk instead of rolling back up the hill. More testing required.
As to why no auto hold, I had turned it off when I was using 2PD cuz I just didn’t love it. And I had never turned it back on when I switched to primarily using 1PD, because 1PD pretty much does that automatically.
If you do leave auto-hold on and use 1-P then at a car wash (er if you do such a travesty to your car like I do LOL) then you'll either have to put it in N while the car is still slightly rolling or use the N-L-Ok procedure to get it to roll.
 

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I think it's a transition from downhill to flat that is causing the problem. The parking lot has a downward incline towards a sidewalk, the sidewalk is level, and then the apron goes downhill again to the street. If I creep up to the sidewalk (going downhill) and then release the pedal so that the front tires just cross into the sidewalk (level), it rolls back up the hill. Not EVERY time, but about half the times I tried just now. Normally, when I feel it rolling back, I jam the brakes because it's pretty unsettling, but tonight, I decided to see what happens. It eventually did stop and the brakes engaged, but only maybe between 1 and 2 feet from the farthest forward I had gotten.
Is the area both your wheels are on down hill and not at a slight incline. Plus you might want to check with a level as the optical illusion of it is happens more offen than you think in the real world. Our eyes are telling us one thing and that is what we tend to trust as humans more than gravity even though gravity says another.
Mix with say the front wheels are on an incline going backwards even though the rear wheels might be higher than the front so gravity ends of forcing the car backwards because the front wheels want to roll backwards a lot harder than it will be from the back. Mix that with brake hold is not going to be super strong.
The reason I ask that is I used to drive a manual hand had some odd roll backwards on what I though should of been a roll forward when I took my foot off the brake before I hit gas. I threw me off but it would happen from time to time and I even knew some spots I could force it and it took some really close looking to figure out the exact cause. Remember the car had zero power when it would happen in a manual.
 
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If you do leave auto-hold on and use 1-P then at a car wash (er if you do such a travesty to your car like I do LOL)
HOW. DARE. YOU.

(Kidding of course. Only handwashes for Shadowfax, even if he does try to take out pedestrians.)

Is the area both your wheels are on down hill and not at a slight incline.
It is definitely a downhill leading to a flat sidewalk leading to a downhill. He rainwater flows to the street, not along the sidewalk.


Mix that with brake hold is not going to be super strong.
In this scenario, the brakes aren't engaging unless I jam them, until after a moment of rolling up the hill. It goes from slowing down the hill to stopping for an instant on the flat, to rolling backwards back up the hill without the brakes catching.
 

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I'm still going to engage @Ford Motor Company over this. That's a scary situation in cities where pedestrians walk close behind cars when they pass the sidewalk.

@OlyPen: I'm using 1PD in engage mode. I haven't tried other drive modes, or auto hold. I'll see if that makes any difference next time I go out.
It's wild behavior. I would appreciate if you can share when Ford answers, especially if it's a helpful response.
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