Suffered medical emergency while driving

[SomeJoe7777]

On the model 3 it’s not the motors that “lock up” in hold mode. It’s the brakes that are actuated by the master cylinder. When my car comes to a stop with hold mode, I can visually see the brake pedal move inward and when I touch the gas it releases. The same operation could be implements on older model S/X easily since the master cylinders all have automation built in for emergency braking/autopilot

You need the PMSR motor to be able to regen down to 0 MPH where the brakes can then be actuated. Pre-Raven Model S/X does not have the PMSR motor, they use induction motors only.

 

[Xminus6]

Pre-Raven Model S and Model X do not have the motor hardware necessary to implement Hold mode.

There is a hold mode on my 2017 X. But I can’t regen to stop and hold.

 

[jfinephilly]

The AP equipped cars I believe have a "hill" mode where if you press hard at a stop it will hold till you apply throttle.

Yes there is a hardware different 3s are permanent magnet motors, the Ravens have those in front but an AC Induction motor in back and the older ones are all AC Induction, and those do not provide any Regen or resistance at very low speeds.

My 3 has induction front motor and magnet rear.

 

[SSedan]

My 3 has induction front motor and magnet rear.

Thank you for the correction. Appears I am too late to edit and correct my first post. Otherwise I would.

 

[vogz]

You need the PMSR motor to be able to regen down to 0 MPH where the brakes can then be actuated. Pre-Raven Model S/X does not have the PMSR motor, they use induction motors only.

I never claimed that they could regen down to 0mph. I simply stated that the “HOLD” feature is a function of the brakes and not the motors.

 

[DopeGhoti]

I believe the 3 uses the regen to bring the speed to 0 before applying the brakes.

Both TACC and Hold mode use a combination of regen braking and friction braking to slow and/or stop the car. The brake pedal can be physically observed to move when the car is automagically slowed (don't stare it it; keep your eyes on the road. Instead, hook your left foot's toe under the pedal's footpad and feel it pull your foot down when it actuates). The brake pedal is physically connected to the friction brakes: if it's moving, the calipers are squeezing. Hold will start actuating the friction brakes late in the process (but it will engage them, and well before your speed is zero), while TACC tends to engage the friction brakes rather earlier.