Car rolls backwards uphill in D

[Earplug]

This might be an issue to report to the NTSB.

https://www.nhtsa.gov/report-a-safety-problem#index

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[jdpdx]

I haven't seen any updates or other conversation around this so I want to share related findings I've had with mine in 1PD.

I have similar issues, but well, in reverse.

I've had issues when I'm going *up* an incline and try to go into reverse.

1st time was a few weeks ago parked in a short drive with a tree at the end. The pitch isn't even that much, just a casual slope. Parked it under the tree to get shade so I could wax it. Turned the car on, put it into reverse and the thing lunged forward. Uh oh. I put it back in park, then back into reverse and tried to back out again. Went forward. This time every sensor is screaming at me that I'm going to hit a tree. I'm screaming at the car that it's going to hit the tree. So I stop again, put it in neutral and try to push...can't budge it.

Ok.

So last ditch is remembering that if my wife's profile is up I know because the car just starts backing up in reverse on it's own in 2PD. So I switch to my wife's profile, put it in reverse and back out fine.

Huh. I wrote it off as a fluke and first year glitch.

Then this weekend it happened again in a different spot. Needed to do a turn around and pulled half way into an apartment parking lot that had a slight incline. Got halfway into the drive, put it in reverse and it just started lunging forward again. So this time I had more space and wasn't going to run into anything so I just kept letting it do the opposite thing. After another 2-3 feet and getting the front tires off the incline it got better.

It seems to be worse in situations where you don't have a flat surface. By flat I mean say parking on the side of a street on a hill. That hasn't given me problems...thank god because that would be a parallel parking nightmare.

It seems to be worse when you are transitioning from the road to an inclined driveway apron or approach. Think of the the space under the car. When you approach an apron from the street and start to go up there's a lot more space under the car in the middle. I don't know if there is a sensor that is freaking out on that but it seems much worse in those variables than general hills/slopes.

 

[Blue highway]

Really interesting 1PD situation. Never had this, it's worked fine for me (blue cruise, not so much )

I wonder...
are all of your modules up to date?
does having hill "hold" on stop this?

It seems like there are circumstances where the car can't tell the difference between decelerating and being tilted front to back. (you have experienced this if you have ever been in one of those simulators that shows a video and tilts you around... being tilted feels just like acceleration up to 1 G)

The car has a tilt sensor (solid state gyro) but I'd expect it to have an accelerometer as well to make 1PD on a hill work predictably. Maybe it doesn't.

 

[i8iridium]

I haven't seen any updates or other conversation around this so I want to share related findings I've had with mine in 1PD.

I have similar issues, but well, in reverse.

I've had issues when I'm going *up* an incline and try to go into reverse.

1st time was a few weeks ago parked in a short drive with a tree at the end. The pitch isn't even that much, just a casual slope. Parked it under the tree to get shade so I could wax it. Turned the car on, put it into reverse and the thing lunged forward. Uh oh. I put it back in park, then back into reverse and tried to back out again. Went forward. This time every sensor is screaming at me that I'm going to hit a tree. I'm screaming at the car that it's going to hit the tree. So I stop again, put it in neutral and try to push...can't budge it.

Ok.

So last ditch is remembering that if my wife's profile is up I know because the car just starts backing up in reverse on it's own in 2PD. So I switch to my wife's profile, put it in reverse and back out fine.

Huh. I wrote it off as a fluke and first year glitch.

Then this weekend it happened again in a different spot. Needed to do a turn around and pulled half way into an apartment parking lot that had a slight incline. Got halfway into the drive, put it in reverse and it just started lunging forward again. So this time I had more space and wasn't going to run into anything so I just kept letting it do the opposite thing. After another 2-3 feet and getting the front tires off the incline it got better.

It seems to be worse in situations where you don't have a flat surface. By flat I mean say parking on the side of a street on a hill. That hasn't given me problems...thank god because that would be a parallel parking nightmare.

It seems to be worse when you are transitioning from the road to an inclined driveway apron or approach. Think of the the space under the car. When you approach an apron from the street and start to go up there's a lot more space under the car in the middle. I don't know if there is a sensor that is freaking out on that but it seems much worse in those variables than general hills/slopes.

Are you using the brake to stop? If you're just relying on 1pd to "stop" you like the OP seems to be describing, it's not meant to be a method to stop and hold the car. If you're using 2pd, then the car is going act exactly like an ICE car where it's going to move when the engine is idle and no foot on the brake.

 

[jdpdx]

I don't understand what you mean by use the 1PD to "stop".

I have tons of use cases where I pull into an inclined spot (nose up, butt down), and have zero issues. When I back out from a flat spot it does the same. Plop down, put foot on brake, hit start. Take foot off brake, put car in reverse, hit accelerator and back out in a shaky studder. 1PD sucks at reverse.

There's just been a few situations where I do that same exact thing and instead of going backwards when I want, it goes forward. And that seems to be specific to some weird angle issue.

 

[tannerk89]

I have this happen to me from time to time as well. 1PD slow down to a stop, then my car slowly creeps backwards up a gradual incline. It’s unnerving because at first you don’t know you’re moving backwards. I was close to hitting a car once because of this. I’ve also had it happen in blue cruise more than once in stop and go traffic. I had to tap the brake pedal to prevent the car from backing up a hill into a stopped car behind me.

 

[Ford Motor Company]

I have this happen to me from time to time as well. 1PD slow down to a stop, then my car slowly creeps backwards up a gradual incline. It’s unnerving because at first you don’t know you’re moving backwards. I was close to hitting a car once because of this. I’ve also had it happen in blue cruise more than once in stop and go traffic. I had to tap the brake pedal to prevent the car from backing up a hill into a stopped car behind me.

Hey there! This does not sound like something you want to happen to your Mach-E. Will you send us a private message with your VIN and local Ford dealer? I can see how I can help.

 

[jdpdx]

Hey there! This does not sound like something you want to happen to your Mach-E. Will you send us a private message with your VIN and local Ford dealer? I can see how I can help.

Good morning, I have a separate thread going on regarding some paint peeling and responded back via DM with my VIN and also mentioned this issue.

 

[Motomax]

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.

Auto hold doesn’t do anything extra when in 1PD because 1PD will auto hold by design. If you look at the auto hold icon, it won’t come on unless you actually touch the brake. Even activated, nothing acts differently from 1Pd. it only acts differently in neutral( 1PD will not hold in neutral).

I always use 1PD and I’ve had it slowly roll back down hill before but it’s not by much and I think it has to do with not lifting off the pedal completely. I’ve also had it roll back downhill in my driveway then correct itself and move uphill. In all cases I’d say it wasn’t more than a foot of travelling.

 

[Mach-Lee]

I always use 1PD and I’ve had it slowly roll back down hill before but it’s not by much and I think it has to do with not lifting off the pedal completely. I’ve also had it roll back downhill in my driveway then correct itself and move uphill. In all cases I’d say it wasn’t more than a foot of travelling.

Agree, same behavior. I just tested it in my sloped driveway, it will only roll the opposite direction about a foot before it stops itself and brakes apply. It will keep rolling if you have the pedal pressed slightly so make sure you lift off completely to stop.

If you have older powertrain software it may be worse, go get the recall done and that may make it better.

 

[jdpdx]

Ideally I'd have a user override that would let me set the drive mode for reverse. I live by 1PD for basically everything. But have hated it since day one for reversing. It's just got an overly hard to press pedal in that mode and the engagement is unlike any other time driving it. You have to press really hard for it to do almost nothing speed wise. It's very unnatural compared to 1PD going forward.

I really prefer the the self propelled nature of reverse under normal 2PD and am almost to the point of creating two profiles to make that work that way. Just use the 3rd memory slot for reverse mirrors and 2PD and then toggle it back after I'm ready to put it in drive.

 

[ohmslaw]

This sounds potentially like they aren’t resetting an integrator quick enough when they are requesting negative torque.

Take this with a grain of salt; I do design control systems for vehicles for a living (just bigger and not with propulsive wheels) and this would be my thoughts.

What is probably being done is there is some type of PI (proportional/integral) control on torque request. When slowing I am assuming that integrator has spooled up to a negative limit. When the vehicle comes to a total stop the integrator should probably reset. If not reset quick enough there might still be a negative torque request.

 

[hbund216]

I think this may have happened to me over the weekend. We were parked with the front wheels on an uphill grade and the rear wheels downhill (Like parked in a V). The car was in one pedal driving mode. I attempted to revers out of the lot. Let go of the brake and the car began to roll forward and getting on the accelerator did not seem to get it to go back. But I hardly pressed the accelerator because I got back on the brakes again. This happens to me when pulling out of our driveway while is a steep downhill and ends at a street that is uphill. Taking the car out of 1 pedal mode got rid of this behavior. I have a video of this and will try to get it and upload it.

 

[DYohn]

One of the many reasons why I don't use one-pedal driving mode.

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