Understanding How Tesla's Shifting Works, Its Protective Protocols, and Neutral

[ACRei]

Please pardon my question. I tend to overthink things (GAD). But instead of ruminating, I figured it'd be best to ask for help in understanding my Tesla.



I've never had a need to use Neutral for my Tesla. I read the manual, and it states that if the Tesla is in Neutral, it can’t shift into Drive or Reverse without first pressing the brake pedal (if going slower than 5MPH).

I was curious if the Tesla would throw out an error if I tried this and sure enough, it does.

I tried this a few times, and 8 times out of 9, the Tesla will scream at you if you try to go into Drive or Reverse while in Neutral.

I was curious about the singular time where I was able to enter Reverse while in Neutral, while rolling forward downhill due to gravity.

Would you guys consider that singular time a malfunction?

Would any harm happen to the Tesla if you were in Neutral, moving forward downhill, then shifted into Reverse and proceeded to press the accelerator? Or does the design of the electric motor negate any potential damage?


Thanks for your patience and any potential help

 

[Gauss Guzzler]

Shifting is just a state of mind in the Tesla. Nothing mechanical or electrical happens, it's just a software setting.

From the motor/inverter/controller standpoint it doesn't matter which direction you accelerate and which direction you're going at the time. It'd be perfectly fine going from 160mph into full-torque reverse if you (and Tesla) wanted it to.

Neutral is also just a state of mind of course. All it does is disable the Gauss pedal and any automatic braking.

The 5mph limit when shifting between any gear is for your own safety, the car couldn't care less. The warnings are just to help you avoid mistakes.

 

[ACRei]

Shifting is just a state of mind in the Tesla. Nothing mechanical or electrical happens, it's just a software setting.

From the motor/inverter/controller standpoint it doesn't matter which direction you accelerate and which direction you're going at the time. It'd be perfectly fine going from 160mph into full-torque reverse if you (and Tesla) wanted it to.

Neutral is also just a state of mind of course. All it does is disable the Gauss pedal and any automatic braking.

The 5mph limit when shifting between any gear is for your own safety, the car couldn't care less. The warnings are just to help you avoid mistakes.

Thank you for the input.


So if I understood you correctly, no harm would happen if I did somehow manage to shift into Drive or Reverse, while in Neutral? The car has no real preference, and any preventative software protocols are purely for the driver's protection?



Regarding its programming, specifically the one that prevents you from shifting into Drive or Reverse from Neutral, if under 8 km/h.
8 times out of 9, the Tesla did prevent me from shifting into Reverse as my car coasted forward in Neutral whilst going downhill.

Why do you think there was that one instance wherein I was able to essentially perform what should've been prevented by programming?

 

[RayK]

I've gotten used to the shifter in my car and it probably has given me a bad habit if/when I ever have to drive my wife's Ridgeline. Of course the position of the shifter is totally different but in my mind I should be able to go from Drive directly to Reverse without having to come to a complete stop.

I park in my driveway tail-first. That means I have to reverse when performing what is essentially half a three-point turn. When I drive up to my house, I turn the wheel to the left and am diagonally positioned across the street before reversing into my driveway. I've been pushing up the control stalk into Reverse while I'm still moving forward. It's only a few miles an hour but I'm not stopping, and if I recall, don't even use the brake pedal (regen is enabled). I've never received any warning message, nor had the car refuse to change "gears".

Going from Neutral to Drive has been a problem at times for me. Before Car Wash Mode and the associated Free roll, when I've gone and washed the car using an automatic tow-through facility, at the end of the line where I have to drive off the ramp when the car is already in Neutral, I'd have to hit the brake before being allowed to shift. Sometimes I could not get the timing right and the workers would be telling me to "go, don't brake, just drive away".

 

[rpiotro]

We understand. Change is hard. Imagine people giving up their horses. You'll quickly get used to it.

 

[ACRei]

I believe the manual said we can shift from Drive to Reverse, and vice versa without any issue, if below 5mph. I like that feature. The transition is so smooth in Tesla's.

I'm trying to understand why the car won't shift out of Neutral into Drive or Reverse, if under 5 mph lol, my best guess is it's a safety feature. Yet you can shift out of Neutral into Drive or Reverse, if going over 5 mph.

Also, I'm trying to figure out how I was able to overwrite the software controls by going into Reverse from Neutral, while coasting at < 5 mph downhill.


Nothing's perfect, I suppose

 

[jjrandorin]

I believe the manual said we can shift from Drive to Reverse, and vice versa without any issue, if below 5mph. I like that feature. The transition is so smooth in Tesla's.

I'm trying to understand why the car won't shift out of Neutral into Drive or Reverse, if under 5 mph lol, my best guess is it's a safety feature. Yet you can shift out of Neutral into Drive or Reverse, if going over 5 mph.

Also, I'm trying to figure out how I was able to overwrite the software controls by going into Reverse from Neutral, while coasting at < 5 mph downhill.


Nothing's perfect, I suppose

It appears that you have been looking into this since at least april of this year, since thats when you posted the same basic question here on TMC. What have you determined during this time (since april) and what is drawing your interest in this fairly niche situation?

 

[ACRei]

It appears that you have been looking into this since at least april of this year, since thats when you posted the same basic question here on TMC. What have you determined during this time (since april) and what is drawing your interest in this fairly niche situation?

I've been paranoid with shifting from Drive to Reverse since I've had 5+ ICE cars until now.

But with Tesla's, it's perfectly fine. There's no mechanism to "break," per se. I'm grateful for that. I honestly like that transition when you back out of a parking spot, and can go into Drive asap.


I suppose I just became a bit worried about Neutral. @Gauss Guzzler helped in giving me more information that essentially Neutral just suspends automatic braking and acceleration.

I know I have overthinking issues. I was just curious how I was able to shift into Reverse from Neutral when the software should've stopped that.


Does anyone have any insight as to why Tesla decided you can't shift into D or R, from N, if going under 5 mph?

 

[Gauss Guzzler]

It's great to have curiosity about these things, and even better to seek a good understanding of the complex machine in which you entrust your life.

My understanding of the shifting logic (excluding Park) is as follows:

• Between +5mph and -5mph you can freely shift between D and R without the brake (for convenience) but cannot shift into N (to prevent mistakes)
• At any speed over +5mph you can freely shift between D and N without the brake. This provides a safe option for people who kick their floormat into the gauss pedal and then don't want to use the brake. Being able to get back into D when coasting at high speeds in traffic is also important for safety.
• At any speed over -5mph you cannot shift at all. You should probably reconsider your priorities in that case.
• When the brake pedal is used you can freely shift between all gears at speeds between -5mph and +5mph.

The Park logic is:

• Between +5mph and -5mph you can freely shift *into* Park from any gear without the brake, but the brake is always needed to shift *out* of Park.
• Beyond +5mph and -5mph the Park button functions as an emergency brake and is only active for as long as you hold it. The brake pedal is not needed to release the emergency brake but if it gets under 5mph it will go into Park and of course the brake is then needed to shift out.
• Note that the emergency brake *intentionally* bypasses the entire hydraulic braking system and all related safety features, so while it doesn't directly hurt the car to use it at high speeds, it could lead to other problems.

 

[al-capone]

Another gear tip. Many first time Tesla owners come to a full stop when going from R to D. Try this... reverse at any normal speed when getting out of your garage but do not press on brake or let go of the throttle when time to shift to D. Just tap the stalk and go to D. Notice how it smoothly slows down and then changes direction...

 

[Gauss Guzzler]

Indeed! No need to lift off the throttle, just tap the gearshift and be whisked off in a new direction!

 

[Tiger]

I know I have overthinking issues. I was just curious how I was able to shift into Reverse from Neutral when the software should've stopped that.


Does anyone have any insight as to why Tesla decided you can't shift into D or R, from N, if going under 5 mph?

The newer S and X versions have automatic gears. In my experience my Model 3 also has some kind of "fuzzy smart logic" to determine when switching to reverse is allowed without pressing the brake pedal. For example, if I drive on road, it often does not allow (switching to reverse without brake pedal), but if I drive onto a parking lot (to do a 3-point turn, for example), it does not require pressing brake pedal.

https://twitter.com/x/status/1360930513935081484

 

[bay74]

Another gear tip. Many first time Tesla owners come to a full stop when going from R to D. Try this... reverse at any normal speed when getting out of your garage but do not press on brake or let go of the throttle when time to shift to D. Just tap the stalk and go to D. Notice how it smoothly slows down and then changes direction...

I wish this worked reliably the other way, going forwards and shifting into reverse. Much of the time it fails for me, presumably because I'm going just a little too fast. Then I have to smash the brakes before I hit the kerb.

I find the shift rules pretty dumb, coming from an old manual without any nannies.

 

[Gauss Guzzler]

Model 3 also has some kind of "fuzzy smart logic" ... it often does not allow (switching to reverse without brake pedal), but if I drive onto a parking lot (to do a 3-point turn, for example), it does not require pressing brake pedal.

No, it's just a simple 5mph rule and it applies everywhere. But I agree it would be better if that limit could be raised to 30mph or 60mph as sometimes I'm in a hurry and don't quite get under the limit before trying to shift.

 

[Mario Veras]

In an ICE vehicle you can always go from N to D while going downhill without any consequences. In fact, it is a good thing to take a down hill and let the car go to N while letting the gravity drive you down if the ICE car has a manual transmission since that saves a bit of gas.

However, on a Tesla, I would not put it on N on a downhill because then you lose all the regen energy to charge your battery. But other than that there should be no harm.

 

[sightman]

In an ICE vehicle you can always go from N to D while going downhill without any consequences. In fact, it is a good thing to take a down hill and let the car go to N while letting the gravity drive you down if the ICE car has a manual transmission since that saves a bit of gas.

However, on a Tesla, I would not put it on N on a downhill because then you lose all the regen energy to charge your battery. But other than that there should be no harm.

I thought shifting to N on an ICE car actually consumed more fuel because instead of the momentum from the wheels turning the engine, the fuel pump is engaged to idle the engine. When in gear and coasting an ICE vehicle will typically not send fuel to the engine.

 

[Gauss Guzzler]

On a Tesla, N is exactly the same as pressing the gauss pedal however much is needed to accelerate/decelerate at the same rate.
On a fossil car, N might use more or less gas than staying in gear, depending on the conditions and auxiliary loads.
On any car, it is foolish, risky, and illegal to coast in N.

 

[Tiger]

No, it's just a simple 5mph rule and it applies everywhere. But I agree it would be better if that limit could be raised to 30mph or 60mph as sometimes I'm in a hurry and don't quite get under the limit before trying to shift.

You're joking, totally unnecessary edge case.

 

[XPsionic]

You're joking, totally unnecessary edge case.

Agreed. That guy's got some wacky ideas.

On a related note, not everyone agrees with how the Teslas can switch from D to R without engaging the brakes below 5mph. Personally I love that feature and use it all the time.

Researcher Asks U.S. To Recall Every Single Tesla After 2013 Over Sudden Unintended Acceleration | Carscoops

A Greek accident investigator is petitioning NHTSA to recall 1.6 million Teslas over their ability to shift from Drive to Reverse without touching the brake pedal

www.carscoops.com

"The ability of some Tesla vehicles to shift from the forward to reverse gear (or vice versa) without the application of the brake pedal is facing increased scrutiny from federal regulators following the submission of a defect petition by a Greek researcher."

“One such ‘special feature’ is the ability of the car to stop and shift into reverse gear when the driver is ready to park, without the requirement of an actual brake pedal activation,” writes Lakafossis. “There is no practical benefit for this potentially dangerous ‘party trick’.”

 

[holmgang]

is reverse enabled via a gear in opposite direction to forward gear, or is it the same fixed gear with the electric motor itself reversing direction?