Scary incident: Car slides backwards after driver exits car

[dorondekel]

I just got a call from the Tesla service manager. He told me that the engineers looked at my log and found nothing unusual. They suggest that the locked back tires slid back on the snow (as some already suggested above) and stopped on its own. By pure coincidence, the stopping happened at the same time I pressed the P button. He was very confident that nothing is wrong with the car and I should be safe to continue driving it as before.

If no one else on the forum experienced or heard of a similar problem, then I guess I'll just accept their explanation.

 

[jerry33]

I just got a call from the Tesla service manager. He told me that the engineers looked at my log and found nothing unusual. They suggest that the locked back tires slid back on the snow (as some already suggested above) and stopped on its own. By pure coincidence, the stopping happened at the same time I pressed the P button. He was very confident that nothing is wrong with the car and I should be safe to continue driving it as before.

If no one else on the forum experienced or heard of a similar problem, then I guess I'll just accept their explanation.

I haven't heard of anyone having this before, but I've certainly had cars slip on ice and snow. Anecdote is that my S has parked on a sloped driveway for six years (121K miles) with no slipping. (Test if I'm going to be driving that day: If I fall down on the driveway, it's too slippery to drive. Yeah, the driveway's that steep.)

 

[dorondekel]

You need a log from Tesla, not just an assurance that everything was normal!

It would confirm what time you pressed P the first time and what time you did the second time.

It would tell you whether the Parking was activated once on the first push or twice with 2 pushes

or only once on first and remained throughout even there were 2 pushes...

The service manager claimed they didn't send him the log and he cannot share it with me. He stated that he was told the log just shows me stopping the car, engaging parking brake and that's it. No other events afterwards. They also reviewed the pictures and believe the small pileup of snow besides the rear tire tracks indicated it was slipping. I pointed out that the picture shows also some side-to-side tread marks in front of the rear wheel, which would not form when the tire is sliding, and that the pile up behind the wheel is small, implying that the slipping distance was short. He said he cannot explain it, but he trusts the engineer that said that everything was normal. The parking brake was pressed only once.

For those into forensics, here's a close up of the rear wheel with arrows showing the features I pointed out to the manager.


By the way, the treads on the tires were quite shallow. I replaced them yesterday.

 

[Vines]

The red arrow you show looks like the mark as you pulled into the driveway, overlaid with the dark sliding mark just to the left of the vehicle travel. Notice how there's no tread marks to the left of the red arrow, just a sliding mark a few feet long at least.
Notice how the edge of the tread which indicates a rolling tire is a couple inches to the background of the photo, compared to the sliding mark and tire, which is just a couple inches to the foreground. It looks to me like it slid backwards on the same marks as it made when rolling forward, except the wheels moved a tiny bit to the left, so the sliding mark from backwards movement, and mark of the shoulder of the tire made when rolling in are just slightly offset.

 

[Tam]

...rear wheel...

The picture does not confirm that it was rolling.

On the contrary, as @Vines pointed out, there was dark mark which definitely proof of sliding. And as you pointed out the pushed up of small mount of snow behind the rear tire proved that it was not rolling over the snow but it was sliding and pushing up the snow.

I would accept the manager's explanation.

I would park in the garage from now on.

 

[dorondekel]

The red arrow you show looks like the mark as you pulled into the driveway, overlaid with the dark sliding mark just to the left of the vehicle travel. Notice how there's no tread marks to the left of the red arrow, just a sliding mark a few feet long at least.
Notice how the edge of the tread which indicates a rolling tire is a couple inches to the background of the photo, compared to the sliding mark and tire, which is just a couple inches to the foreground. It looks to me like it slid backwards on the same marks as it made when rolling forward, except the wheels moved a tiny bit to the left, so the sliding mark from backwards movement, and mark of the shoulder of the tire made when rolling in are just slightly offset.

Yes, you are right. I think it stopped so suddenly because the locked back wheels hit a dry patch. The synchronizing between the P button press and the immediate stop was so perfect, I was totally convinced it was a cause and effect, but freak stuff happens.

Now I feel guilty for the title of the thread being misleading. Is there a way to edit it? I couldn't find one.

 

[jerry33]

Yes, you are right. I think it stopped so suddenly because the locked back wheels hit a dry patch. The synchronizing between the P button press and the immediate stop was so perfect, I was totally convinced it was a cause and effect, but freak stuff happens.

Now I feel guilty for the title of the thread being misleading. Is there a way to edit it? I couldn't find one.

I believe the moderator can edit the title.

 

[dorondekel]

I believe the moderator can edit the title.

How do I contact the moderator?
Sorry, I'm a new member. I searched but couldn't find a way to do that.

 

[jerry33]

How do I contact the moderator?
Sorry, I'm a new member. I searched but couldn't find a way to do that.

Click on "members" then "staff members". they'll point you in the right direction.

 

[commasign]

How do I contact the moderator?
Sorry, I'm a new member. I searched but couldn't find a way to do that.

Or click the "report" button at the bottom left of your post.

 

[MP3Mike]

How do I contact the moderator?
Sorry, I'm a new member. I searched but couldn't find a way to do that.

You can just click the "Report" link on the post and put in what you would like the title changed to.

 

[dorondekel]

Just asked for a change of title.
Many thanks to all who responded. It was very helpful!

 

[mswlogo]

This was suggested earlier, but it doesn't explain how I managed to stop the car (abruptly, on the spot) by pressing the P button. If pressing the P button made such a dramatic and immediate difference, the car was not in P before I pressed it. Besides, my driveway is not nearly as steep as the one in the video, and the snow was very light with no ice underneath.

First of all I believe you something went very wrong.

The snow pile behind the wheel was probably from when you did manage to put it in park (in Panic mode) it skidded to a stop.

If you look in front of the rear wheel you can see tracks from pulling in (with tread grooves showing). And a track from going back out that is not exactly on the same path. But for about half a wheel diameter (to the left) and for a good couple feet it does look like it was sliding rather than rolling.

Problem is, it's hard to know if that sliding happened before you hit the P (the Panic P) or after.

How quickly did it stop when you hit the P (the Panic P).

By chance did you also hit the brake?

The chances of you forgetting to hit P AND the automatic P failing to initiate when getting out are really low.
And if it did fail for what ever reason. Why did it suddenly work?

Will an Alarm sound if it's in N (intentional or not) and you get out? Could it have erroneously gone into N?

It certainly doesn't look like it's enough snow to have the car slide out (with 2 wheels locked) of that slight incline.

Is Summon active on this car?

 

[daxz]

For peace of mind, whenever I park with a slight hill I push and hold the parking stalk for a few seconds. A brake indicator lights up on the instrument panel. I've had a non-Tesla stick shift car roll on me before.

https://www.tesla.com/sites/default/files/model_s_owners_manual_north_america_en_us.pdf Page 67

Warning: In snowy or icy conditions the rear wheels may not have sufficient traction to prevent Model S from sliding down a slope, particularly if not using winter tires. Avoid parking on hills in snowy or icy conditions. You are always responsible for parking safely

 

[dorondekel]

How quickly did it stop when you hit the P (the Panic P).

By chance did you also hit the brake?

The chances of you forgetting to hit P AND the automatic P failing to initiate when getting out are really low.
And if it did fail for what ever reason. Why did it suddenly work?

Will an Alarm sound if it's in N (intentional or not) and you get out? Could it have erroneously gone into N?

It certainly doesn't look like it's enough snow to have the car slide out (with 2 wheels locked) of that slight incline.

Is Summon active on this car?

I could not hit the brake, because I was stretched across the front seat sideways.
The stop when I pressed P was very quick (I felt a jolt). The car could have slipped some distance, but probably not more than, say, 50cm.
There was no summon active, and, as I explained above, the car could not have been in N (it would have started rolling once I released the brakes.

I think I noticed that the front wheels were turning as the car started sliding back. However, I learned today that the parking brake doesn't apply to the front wheels, unfortunately, so this is not evidence of anything.

My wife, who came out to the driveway shortly after the incident, is also skeptical about the sliding explanation, confirming that she didn't feel any loss of friction when she walked towards my car.and around hers, which was parked besides mine. However, on balance of evidence, I tend to accept Tesla's explanation, at least until it happens again (to me, or someone else).

 

[mswlogo]

I could not hit the brake, because I was stretched across the front seat sideways.
The stop when I pressed P was very quick (I felt a jolt). The car could have slipped some distance, but probably not more than, say, 50cm.
There was no summon active, and, as I explained above, the car could not have been in N (it would have started rolling once I released the brakes.

I think I noticed that the front wheels were turning as the car started sliding back. However, I learned today that the parking brake doesn't apply to the front wheels, unfortunately, so this is not evidence of anything.

My wife, who came out to the driveway shortly after the incident, is also skeptical about the sliding explanation, confirming that she didn't feel any loss of friction when she walked towards my car.and around hers, which was parked besides mine. However, on balance of evidence, I tend to accept Tesla's explanation, at least until it happens again (to me, or someone else).

That's a good point why it started to move AFTER you got out.

Keep a close eye on it.

 

[bmah]

Moderator note: Edited thread title per request, to reflect general conclusions about what happened.

Glad all are safe!

Bruce.

 

[TampaRich]

Wow, so many nightmare stories from 1st time posters these days.

 

[frenchie22]

I've had my p85 and my p90 both slide after parking on an incline with slush or ice on the ground. It's due to how the parking brake works and its exacerbated by how aggressively it locks.

 

[dorondekel]

I've had my p85 and my p90 both slide after parking on an incline with slush or ice on the ground. It's due to how the parking brake works and its exacerbated by how aggressively it locks.

The tires I had on were the original ones, and they were replaced by Tesla after the incident to the same "all season" Michelin ones (Primacy mxm4). I drove on these tires for 4 long winters now, and they are fine on packed snow, rain and slush, but I noticed that a couple of times I slid when stopping on freshly fallen loose snow, which is what was on my driveway that day (albeit only a little bit of it).

I never had trouble going up the driveway to get into the garage, even just before the incident, but driving up is using all 4 wheels, while the parking brake uses only 2. Why don't they apply the front brakes too in P? Cost saving? Beats me.

Next winter I'm going to switch to snow tires.