P mode vs Park mode

[Mario Veras]

What’s the difference between putting the Model 3 in P versus Park mode? I’ve seen some YouTubers talk about that it makes no difference, so why is there a logo displayed on the screen if it makes no difference?
I can’t seem to find this in the manual.

 

[mtmra70]

...and further to my point, if I put the car in park then go to the screen to set the parking brake, it notes that it is already set.

So if there were truely two different modes then one should expect to see the parking brake status set and not set. However, in both short and long press of P it notes that the parking brake is set.

 

[mtmra70]

They are two different systems and must be for safety reasons. If standard braking fails, you must have a second method available to you for engagement of the brakes.

Yes, there are two different ways to drive and engage the brake, we see this on a lot of vehicles, like you noted.

However, when putting it in short P vs long P they appear to be an identical processes which is engaging the "parking brake" in both cases....or Tesla is just lieing on their parking brake screen...which could be true too...lol

 

[launchd]

I just got in my M3LR and was able to engage park and then the parking brake. Two different noises. Maybe the M3P engages both at the same time?

 

[android04]

I just got in my M3LR and was able to engage park and then the parking brake. Two different noises. Maybe the M3P engages both at the same time?

They both just activate the EPB motor (Park mode and Parking Brake). The brake booster and hydraulic brakes are not used as the parking brake because it is powered down when the car is parked and asleep. The EPB motor is what is used to clamp down the brake pads in both cases because it will hold the pressure even with no power. Have you never heard the EPB motor whine when you first get in the car and put the car in Drive (assuming you don't always engage the Parking Brake). The hydraulic system and the EPB work together in regular park, but ultimately the EPB motor is what clamps down and holds even when the car is off or it has no power.

Now here is one difference that I have noticed between Park and Parking Brake: when you enable regular park and are on an incline or are otherwise in a situation where the car can roll a little bit it will because there is a slight delay in clamping down the EPB when you let go of the brake pedal. If you press and hold the Park button to engage the Parking Brake, it clamps down right away so the car will not roll down at all when you release the brake pedal.

 

[mtmra70]

When I short press Park I get this. It indicates the parking brake is applied, but does let you "press" the button (turns on red P indicator). This could be one of those legal things? Either way, its saying the parking brake is applied.

If I press it all you hear is a quick "tick" sound, which I believe is it attempting to drive the motor again, or maybe some relay. It is not the same sound if I'm in N and press the button, which is the long drive sound/pedal feel you get when doing either the short P, long P, or pressing this button while in N.

 

[DerbyDave]

Non performance models, including Long Range, had a separate Parking brake caliper thru early 2021.

 

[gearchruncher]

@launchd is completely wrong here.
The iBooster isn't involved at all.
You can prove this by datalogging break pressure.
Or just by observing that the brake pedal doesn't move.

 

[android04]

Non performance models, including Long Range, had a separate Parking brake caliper thru early 2021.

The Model S and X had a separate Electronic Parking Brake caliper up to year 2021. All Model 3 and Y and newer than 2021 Model S and X have the EPB integrated into the rear brake calipers.

 

[mtmra70]

@launchd is completely wrong here.
The iBooster isn't involved at all.
You can prove this by datalogging break pressure.
Or just by observing that the brake pedal doesn't move.

My brake pedal moves when putting it in park *shrug*

 

[gearchruncher]

My brake pedal moves when putting it in park *shrug*

Only if your foot is already on the brake.
It moves because the rear electronic parking brake moves the rear caliper pistons, which will cause the pedal to move some if already depressed.

 

[T4M3]

I just got in my M3LR and was able to engage park and then the parking brake. Two different noises. Maybe the M3P engages both at the same time?

I can confirm the same in my 2022 M3LR. I was able first to engage park and then the parking brake and there are definitely two different noises.

 

[android04]

I can confirm the same in my 2022 M3LR. I was able first to engage park and then the parking brake and there are definitely two different noises.

The difference in sound is the difference in sound between the parking brake motor being able to turn some (Park mode) and being stalled (Parking Brake). If Tesla would let us activate Park Brake over and over again you would hear the same sound over and over again, but once it is applied once it will not let you apply it again.

 

[rrolsbe]

Great discussions. Maybe I missed this but how do you use the park brake, if the hydraulic brakes totally fail, for emergency stopping? I assume there must be a way to stop the car if the normal braking method totally fails. If the parking brake is used while the car is in motion, it would need to be smart enough to brake in a controlled manner (not lock up). Using the park brake to stop the car is be something I would like to try at low speed.

 

[mtmra70]

Great discussions. Maybe I missed this but how do you use the park brake, if the hydraulic brakes totally fail, for emergency stopping? I assume there must be a way to stop the car if the normal braking method totally fails. If the parking brake is used while the car is in motion, it would need to be smart enough to brake in a controlled manner (not lock up). Using the park brake to stop the car is be something I would like to try at low speed.

Press and hold Park. Though the motor regen should slow you down pretty quick as it is.

 

[DerbyDave]

Press and hold Park. Though the motor regen should slow you down pretty quick as it is.

Correct... This procedure is in the manual for emergency braking if the hydraulic brakes go out.

 

[rrolsbe]

Correct... This procedure is in the manual for emergency braking if the hydraulic brakes go out.

Thanks for the replies! Has anyone tried this emergency braking method when there is no regen or is very limited due to cold HV battery cells?

 

[gearchruncher]

Thanks for the replies! Has anyone tried this emergency braking method when there is no regen or is very limited due to cold HV battery cells?

Yes, I have in both my Model X and 3. In the snow it's a lot of fun and lets you spin the car as it locks up only the rear axle, just like an old school "emergency" brake.

You all are aware that electronic parking brakes are the standard now on almost all cars? And that Teslas aren't any different? The parking/emergency brake is actuated both when you put it in park, and when you request manual activation. It's just that on a Tesla the way you request manual activation is by holding the park button.

 

[DerbyDave]

Thanks for the replies! Has anyone tried this emergency braking method when there is no regen or is very limited due to cold HV battery cells?

There is new software to equalize battery regen and braking that you can set so it feels the same all the time. It is in some software versions now, if not, yours soon. You should only use the emergency brake for an emergency, according to the manual.

Regenerative Braking​

Available in the United States
Has Regen Backfill
Models: S 3 X Y
Your vehicle can now automatically apply regular brakes for consistent deceleration when regenerative braking is limited due to battery temperature or state of charge. To enable, tap Controls > Pedals & Steering > Apply Brakes When Regenerative Braking Is Limited.
Editor's note: This feature has been added to additional regions and vehicles.

 

[gearchruncher]

I was able first to engage park and then the parking brake and there are definitely two different noises.

Like mentioned above, the distinct noise is because you are re-engaging the same brake. This is covered in detail in the linked thread.

 

[gearchruncher]

It is in some software versions now, if not, yours soon.

Not all Teslas have compatible hardware with this update. Some cars will never get it.