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Safety mode when driving through standing water

ICE vehicles don't do that when driving down the highway in the rain. What is the car protecting itself from, since it was able to continue on its way, do other ICE's on the same road need to protect themselves? This is obviously a glitch, maybe the car is just being "over" protective, but it's not welcome behavior.

How is it a "glitch" if it was designed to do that? :confused:

No, ICE vehicles don't have that safety feature and maybe they should? Sorry if this sounds a little flippant but I have $100k worth of EV and I'm happy the car is designed to protect itself when it thinks it's at risk of submersion.
 

jerry33

(S85-3/2/13 traded in) X LR: F2611##-3/27/20
Supporting Member
Mar 8, 2012
20,813
29,683
Texas
No, ICE vehicles don't have that safety feature and maybe they should? Sorry if this sounds a little flippant but I have $100k worth of EV and I'm happy the car is designed to protect itself when it thinks it's at risk of submersion.

Between the two choices:

1. Go to neutral and slow when submersion may happen.

2. Continue until something shorts out.

I'll take door number one.
 

JRP3

Hyperactive Member
Aug 20, 2007
23,908
67,045
Central New York
I'm suggesting that it's too sensitive, maybe it needs a bit of a time delay to differentiate between a splash that is harmless and an actual problem. Read the experience of the person driving down the highway in the rain, he was not crossing deep water from the sound of it. This car should be well protected from water ingress.
 

montgom626

Active Member
Dec 15, 2012
1,328
1
USA
How is it a "glitch" if it was designed to do that? :confused:

No, ICE vehicles don't have that safety feature and maybe they should? Sorry if this sounds a little flippant but I have $100k worth of EV and I'm happy the car is designed to protect itself when it thinks it's at risk of submersion.

ICE in high water can self destruct with water entering a running ICE. Bad news...............
 
Agree that some issues like this could be avoided if there was a comprehensive manual but I do have an answer......

I spoke to someone senior at Tesla today and he told me that, like any other car, going at speed through water high enough to hit the bumper is not a good idea. When it thinks it's being submerged, Model S puts itself into neutral and "safe mode" to prevent any big problems. All the customer has to do is put the car back into drive and there's no issue. The cars mentioned up-thread sound like they are performing exactly as they should, protecting themselves and the occupants.

As this was told to me by Tesla, I'm going to update the thread title to reflect that this is now a known safety procedure.



(P.S. my contact also pointed out that it's a performance sedan and not a Hummer! My exclamation mark)

I hope that the senior engineers are not as cavalier about this issue as the person you reached. If it is as sensitive as has been suggested here, someone will get into an accident. Going from 70mph into neutral in the fast lane of metropolitan highways is very dangerous. If it just takes driving on a freeway during a heavy rainstorm (like we have here EVERY DAY in the summer here), it is no longer my daily driver (for safety reasons). It would be a substantial impairment of the USE and SAFETY of the vehicle.

- - - Updated - - -

How is it a "glitch" if it was designed to do that? :confused:

No, ICE vehicles don't have that safety feature and maybe they should? Sorry if this sounds a little flippant but I have $100k worth of EV and I'm happy the car is designed to protect itself when it thinks it's at risk of submersion.

It is a "glitch" if the design is such that it "thinks" it's at risk when it is not. If it shifted itself into neutral because it felt a drop on the windshield would that be okay? Obviously not. If it shifted into neutral when it was completely submerged, would that be okay? Of course. It is no longer a glitch somewhere in between. It's possible (based on at least one report) that it is not set correctly. This must be fixed. Your conversation with Tesla makes it seem like they are dismissive of it and are unwilling to believe that it's set incorrectly. This is very, very worrisome to me. Since it's second-hand, I'll give them the benefit of the doubt, and choose to believe they will work on it.
 

swegman

Active Member
Mar 27, 2012
1,580
1,645
As one who has not yet received their car, I am concerned by this and take with a grain of salt what the tesla person told you. Perhaps that is the way the car was designed, and if it is, there must be a notice provided by tesla to this effect no later than at the time of delivery, such as publishing a notice in the owner's manual or posting a notice on the website. As of right now, I am inclined to believe that the matter is being dismissed, maybe because it is the holiday season and tesla is overloaded, or perhaps because tesla does not wish to overly concern people that there is a problem until they get to look into the matter.

It has been my experience that manufacturers are quick to initially dismiss customer's concerns. I am not saying that tesla is doing such. But if this issue is a "feature" of the car that does not require fixing, they need to inform all the current, future and potential customers of this "feature".
 
Going from 70mph into neutral in the fast lane of metropolitan highways is very dangerous.
Driving at 70mph through standing water is very dangerous.


If it shifted into neutral when it was completely submerged, would that be okay?
No, IMO that wouldn't be okay. It would be too late.


Your conversation with Tesla makes it seem like they are dismissive of it and are unwilling to believe that it's set incorrectly.
Unless you're spying on me you have absolutely no idea what the tone was. I'm not defending anyone but I'm equally not sure why you need to see it as a major problem that Tesla is working on? If the drivers concerned reported their issues to Tesla I'm 100% certain it will be formally reviewed to make sure there's no safety issue. I was repeating the message I received saying that (at least as far as the stated posts in this thread are concerned) the car acted as it is programmed to do so.
 
Agree that some issues like this could be avoided if there was a comprehensive manual but I do have an answer......

I spoke to someone senior at Tesla today and he told me that, like any other car, going at speed through water high enough to hit the bumper is not a good idea. When it thinks it's being submerged, Model S puts itself into neutral and "safe mode" to prevent any big problems. All the customer has to do is put the car back into drive and there's no issue. The cars mentioned up-thread sound like they are performing exactly as they should, protecting themselves and the occupants.

As this was told to me by Tesla, I'm going to update the thread title to reflect that this is now a known safety procedure.


(P.S. my contact also pointed out that it's a performance sedan and not a Hummer! My exclamation mark)


exactly. this. i would think this behavior is exactly fine for the circumstances. sounds safe and smart. and not terribly inconvenient (unless your car never restarts..:) )

i do agree however, that this mode, behavior, like many other things, should be noted in a more comprehensive manual for the car. there are many things it does, and modes it gets in, that are not documented. the manual is more like a macbook pro manual, where 'we'll tell you everything you need to know to get going...', but the really inside intricacies we'll save you from. laptop, ok.. car, maybe not.... what we need is the 'model s: the missing manual'.... or, 'model s for dummies'??

lol.

anyway....
 
Driving at 70mph through standing water is very dangerous.

It depends what you mean by "standing water". For all definitions of standing water, your statement is not true (for most cars).

Quote taken out of context snipped.

Unless you're spying on me you have absolutely no idea what the tone was. I'm not defending anyone but I'm equally not sure why you need to see it as a major problem that Tesla is working on? If the drivers concerned reported their issues to Tesla I'm 100% certain it will be formally reviewed to make sure there's no safety issue. I was repeating the message I received saying that (at least as far as the stated posts in this thread are concerned) the car acted as it is programmed to do so.

Unless you misreported your conversation, there was enough there to characterize it as dismissive, by definition. Tone played no part it in and I never characterized the person's tone.
I agree with your follow-on statement to the extent that I am sure it will be formally reviewed -- your contact's statement notwithstanding.
 
After thinking about this some, I think it actually makes a lot of sense.

First, if conditions are such that there is standing water on the road--enough to set off this behavior--then speed should be less and following distance more than in drying conditions.

If a sensor in an air intake is detecting immersion (needs to be much more than just a splash), then as far as the car is concerned the driver is trying to continue forward through deep water. Switching to neutral is the fastest way (short of uncommanded braking, which would definitely NOT be a good idea) to reduce the amount of intruding water, as a wake would have developed ahead of the car as it was pressing through the water. In neutral, the hydrodynamic force of the water would then slow the car and allow the water buildup ahead of the car to dissipate.

Do I think this behavior is dangerous? No--as long as the driver expects it as a possibility. So I think the behavior is OK--however Tesla needs to put these things in the manual for everyone's safety.

Having said that though, if this was set off by simply speeding through a puddle then the threshold for setting off the alarm is too low.
 
After thinking about this some, I think it actually makes a lot of sense.

First, if conditions are such that there is standing water on the road--enough to set off this behavior--then speed should be less and following distance more than in drying conditions.

I appreciate what you are trying to say, but personally, I would make some changes. You say "enough to set off this behavior". That assumes that the sensors are set correctly. It could be set to "just a splash" at the extreme (as you mention below). So you can't just say "enough to set off this behavior" unless you know that this level is correct. Also, I have no control over following distance of the person behind me (and it's almost never where it should be, no matter what the conditions).

If a sensor in an air intake is detecting immersion (needs to be much more than just a splash), then as far as the car is concerned the driver is trying to continue forward through deep water. Switching to neutral is the fastest way (short of uncommanded braking, which would definitely NOT be a good idea) to reduce the amount of intruding water, as a wake would have developed ahead of the car as it was pressing through the water. In neutral, the hydrodynamic force of the water would then slow the car and allow the water buildup ahead of the car to dissipate.

Do I think this behavior is dangerous. No--as long as the driver expects it as a possibility. So I think the behavior is OK--however Tesla needs to put these things in the manual for everyone's safety.

As mentioned above, I don't think you can say that the behavior is OK, unless you know that it's not just a splash, which you don't know yet. I would go a level above "just a splash" and say that if it's typical highway in heavy rain level, that is too sensitive too.
 
As mentioned above, I don't think you can say that the behavior is OK, unless you know that it's not just a splash, which you don't know yet. I would go a level above "just a splash" and say that if it's typical highway in heavy rain level, that is too sensitive too.

Right--I'm not saying the threshold is correct. I don't even have my car and I wasn't there when it happened to other drivers. The threshold may very well be way too low. However, what I'm saying is that the car's reaction to sensing immersion seems to make sense to me. We just don't know if the amount of water that sets off this reaction is correct.

As far as the following distance behind you, correct--you have no control over that. I'm tailgated every day, as most people on this forum probably are. But in my current ICE, there are often cases where I lift off the accelerator (which is a stronger deceleration than just shifting to neutral), and sometimes I need to do it while being tailgated. If the moron tailgating behind me smashes into me because of it, well then s**t happens and the driver in back just has to suffer the consequences of his own idiocy...higher insurance premiums, etc.

(Spoken from someone who's been rear-ended twice in the last year--both times sitting at a stop light. Let's hope that trend is over).
 
I'm a bit torn as far as how I feel on this topic. On the one hand I like the car going into a safety mode to assess the status of the system if it gets submerged but on the other hand it seems way too sensitive based on user accounts. The problem I'm seeing arising is what an inexperienced driver would do in this situation. Someone who doesn't know any better could just freak out with a bunch of WTFs avert their eyes from the road and an unfortunate incident could happen. A 1 second change of nominal operating behavior is plenty of time for something to happen. And a more detailed manual would only help those that would mostl likely already know how to handle themselves in this saftey mode situation.

I'm ok with the behavior but the way it is now it is a PR nightmare waiting to happen due to people who wouldn't know how to properly handle a vehicle when this safety mode activates

One driver mentioned that the warning message just flashed and went away with not enough time to read it. There's so much screen real estate. Tesla should let the driver know in an easy to find location when system anomalies like this happen and keep it there for a reasonable duration even after the system determined everything was ok. Maybe by overriding one of the displays by the steering wheel.

Thanks to those members that are letting these types of situations known to the forum members.
 
One driver mentioned that the warning message just flashed and went away with not enough time to read it. There's so much screen real estate. Tesla should let the driver know in an easy to find location when system anomalies like this happen and keep it there for a reasonable duration even after the system determined everything was ok. Maybe by overriding one of the displays by the steering wheel.
Agree. If this is truly intended behavior, I don't see why the alert message doesnt' stay up on the screen and featured more prominently. Flashing lights and sounds, put into neutral with no information is not a proper safety alert.
 

JakeP

S P4996 ==> P02547
Supporting Member
Apr 27, 2012
1,862
164
Bradfordwoods, PA
Thanks for digging into this NigelM, it is good to know that this is "intended behavior", even if it is a bit of an undocumented feature, which is surprising for something with an obvious safety impact when operating at speed. The Manual needs to state this in a big, bold font somewhere, I would think.

Perhaps now the engineers will review if this behavior is the best approach, or if alternatives should be explored (such as perhaps instantly raising the suspension to High or even Very High, depending on where the sensors are and what measurements they are making).
 
One driver mentioned that the warning message just flashed and went away with not enough time to read it. There's so much screen real estate. Tesla should let the driver know in an easy to find location when system anomalies like this happen and keep it there for a reasonable duration even after the system determined everything was ok. Maybe by overriding one of the displays by the steering wheel.

A good idea--hopefully it gets incorporated into a future firmware release.
 

GLDYLX

Member
Dec 22, 2012
102
150
CA
As a manual transmission driver, I'm not sure why dropping into neutral in >4" water is a problem. When I start to lose traction in deep puddles, I always automatically engage my clutch, letting momentum take me forward until I can feel the tires start to grip, and release the clutch in the appropriate gear. Perhaps that's not the *correct* thing to do, but it's worked nicely for me for 35+ years of (apparently aggressive) driving.

Perhaps the drop into neutral is triggered by the TC function, essentially doing what I do to avoid out-of-control hydroplaning.

Of course, all drivers MUST be informed of this behavior BEFORE they start tooling around, a message should appear AND STAY on the touchscreen until the car is put back in gear, and I would hope that the brake lights (or hazards) come on (temporarily) when it happens, to warn those behind, who might not see the upcoming puddle...

Just sayin’.
 

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