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Tesla 3 Surges Backwards while Parallel Parking

How hard are you accelerating in reverse that your body shifts noticably?

I back into my garage every day in hold mode and it's never come remotely close to being an issue, concern, or danger.
Thanks, my estimate is that the acceleration was virtually maximum. From a full stop no more than 2 metres (6 feet) away the impact crumpled the whole front end of the car ahead.

As with you in your garage, I have done exactly (I think) the same thing hundreds of times without any hint of a problem.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
14,973
19,339
San Diego
Thanks, my estimate is that the acceleration was virtually maximum. From a full stop no more than 2 metres (6 feet) away the impact crumpled the whole front end of the car ahead.

As with you in your garage, I have done exactly (I think) the same thing hundreds of times without any hint of a problem.

(I assume you meant the whole front end of the car behind.)

Yeah, sounds like you most likely hit the accelerator by mistake. It can happen. I've nearly done it in Hold Mode a couple times. Probably best to use Creep until you are very familiar with the vehicle. And be cognizant of the potential ways that Hold Mode can lead to disaster (being aware of the ways things can go wrong may make them less likely). Personally, I live in a state of perpetual abject terror of slamming into something because I use Hold Mode, and I know that someday I'm just going to slam that accelerator to the floor. But I love it so much, I can't quit it. YOLO.
 
The OP could have been hung up on something (driving by "feeling the curb"), or whatever.

Unintended acceleration when driving a relatively unfamiliar car is not that unusual. Been going on for decades. For the reasons mentioned by Daniel, Hold Mode does probably make it more likely. (I use Hold Mode.)

Here's what someone did to my first car. They were just parked in front of me and kind of hit the gas a bit too hard when backing up. Driving a car borrowed from their mom. 2002. They left a note explaining what they thought happened (good on them...).

View attachment 517273
View attachment 517275
Thanks Alan. Yes, my first thought was that a wheel had hung up and sprung free--perhaps. but I'm not sure. The damage was much more severe than in your photos, and I hit the other car squarely in the centre. It wasn't inexperience; I have driven T3 for five months and over a million miles total (without accident).

I'm pursuing this because I don't want any repeat--me or anyone else.
 
Yeah, sounds like you most likely hit the accelerator by mistake.
His foot was on the accelerator because he was in hold mode. I don't think he said that he moved it to the brake.
Makes me wonder if there could be some stickiness or latency to the ibooster control which could cause the car to lurch backward when it breaks free causing ones body to fly forward. Sounds like a positive feedback system to me!
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
14,973
19,339
San Diego
His foot was on the accelerator because he was in hold mode

Yes, agreed. Foot is pretty much always over the accelerator when using Hold mode. Like I said, I live in a very, very fearful state.

ibooster control

What is this?

first thought was that a wheel had hung up and sprung free--perhaps

If you were pressing accelerator without a response that seems likely.

I have driven T3 for five months

Yeah, but that is not all that long. In any case, accidents happen. My main point is that it is not that unusual to have pedal misapplication, or excessive application, in the case of lack of pedal response. Definitely understand the desire to understand what you did wrong (it's a good way to reduce the chances of doing it again!). It's possible Tesla could provide you the data, so you can figure out what you did wrong, for certain. But might not be worth the runaround.
 
How hard are you accelerating in reverse that your body shifts noticably?

I back into my garage every day in hold mode and it's never come remotely close to being an issue, concern, or danger.
If I were planning on accelerating quickly it wouldn't be a problem. It sounds like this was an unplanned acceleration event in which case he might not have been bracing himself enough to quickly lift his foot off the accelerator. Maybe the brakes were sticking or there was a lip or a bug in the brake control algorithm and when it broke free it caused his body to lurch forward. Seems possible.
What is this?
electromechanical brake booster. iBooster
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
14,973
19,339
San Diego
a bug in the brake control algorithm and when it broke free it caused his body to lurch forward. Seems possible.

You'd have to explain this a bit more...presumably the brakes weren't involved here since the driver's foot was on the accelerator, not the brake? I guess I'm not sure I'm following this explanation and how it relates to Hold mode.
 
You'd have to explain this a bit more...presumably the brakes weren't involved here since the driver's foot was on the accelerator, not the brake? I guess I'm not sure I'm following this explanation and how it relates to Hold mode.
I believe, could be wrong, that Hold mode blends the brake and motor control at low speeds.
I seem to recall someone logged data and made a plot comparing the three modes but I can't find it.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
17,580
23,639
Riverside Co. CA
Thanks Alan. Yes, my first thought was that a wheel had hung up and sprung free--perhaps. but I'm not sure. The damage was much more severe than in your photos, and I hit the other car squarely in the centre. It wasn't inexperience; I have driven T3 for five months and over a million miles total (without accident).

I'm pursuing this because I don't want any repeat--me or anyone else.

With that much damage (as mentioned) the pedal was pressed more than "lightly" would be my guess. Enough to override the low speed collision detection. The car will accept driver input to move, even if it thinks it shouldnt.

If you "dont want a repeat" you should use creep mode as mentioned so that you are rolling forward and hovering over the brake instead of using the accelerator / go pedal. I use hold mode every day to pull into my garage but I have a decent amount of space. I also know how to parallel park, but do not parallel park anywhere that I can avoid it (I dont like parking on the street). I will walk further to avoid parallel parking, from personal choice. If I was parallel parking, I would use creep mode.

No way for you to "not have a repeat for anyone else" because hold mode vs creep mode is a personal choice allowed by the car. As long as cars have had accelerators, people have pushed the wrong pedal or pushed the pedal "too hard" so you need to focus on how you prevent "yourself" and "others that drive your car" from doing this, and not worry about "everyone else".
 
I firmly believe that "creep mode" should be the default while in reverse. I like one-pedal driving, but I absolutely hate using the accelerator pedal to back up. It shouldn't even be an option to use regenerative braking in reverse.

Personal question for the OP: Are you by chance, short in height? I own a driving school. Most people keep the heel planted, but there are a few people who cannot... especially if they're trying to look over their shoulder through a relatively small rear window.

If a driver is unable to keep the heel planted (or if he/she just doesn't for whatever reason), then when the car is in reverse, acceleration will tend to be "amplified" as the leg tends to be "thrown" toward the accelerator if the car moves even a little bit abruptly. (The same is true of the brake pedal when moving forward if the heel isn't planted.)
 
Back when I did Desktop Support IT jobs for companies, we commonly referred to this as a PEBKAC problem -- Problem Exists Between Keyboard And Chair.

If you're using Hold mode it can be touchy until you get used to it.

I'm also a former software developer. Often, even if the "Problem Exists Between Wheel And Seat" (PEBWAS)... Poor design greatly contributes to the likelihood that the user (driver) will not behave as the designers intended.

In this case, Tesla should require creep mode for reverse. This issue is likely to reoccur until such change is made. I doubt the OP is the only such case.
 
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TLLMRRJ

Active Member
Dec 19, 2019
2,163
2,621
Houston
Back when I did Desktop Support IT jobs for companies, we commonly referred to this as a PEBKAC problem -- Problem Exists Between Keyboard And Chair.

If you're using Hold mode it can be touchy until you get used to it.

We had several terms that we commonly used to refer to Desktop IT Support people that only knew how to tell you to reboot your PC, even though you did that 5 times before hesitantly calling support, and if that didn’t work, they just jumped straight reimaging your PC.

But we won’t list those terms here.
 
We had several terms that we commonly used to refer to Desktop IT Support people that only knew how to tell you to reboot your PC, even though you did that 5 times before hesitantly calling support, and if that didn’t work, they just jumped straight reimaging your PC.

But we won’t list those terms here.

The correct term is "incompetent". By definition, that's not troubleshooting.
 

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