2017~2024 Parking brake sometimes engages automatically

[edbern]

I know there are other threads about this but they seem to wander off onto other topics without a conclusion.

I have a very simple question.

Sometimes when I park my 2017 Touring, the electronic parking brake engages automatically. Sometimes it doesn’t.

But I cannot for the life of me determine the conditions that allow that to happen.

I have tried it with and without auto hold engaged, with and without seatbelt on, door open etc. Plain and simple, does anyone know exactly what conditions have to be occurring for the electronic parking brake to engage automatically? I like the feature and want it to happen. I just don’t know how to ensure that it does.

Many thanks.

 

[shadonoz]

My informal observation is:
1- auto hold on
2- tranny to P
3- seat belt off
4- ignition off
Try that and see. Not sure if switching 3 and 4 matters.

But when it happens: BINGO!

 

[edbern]

My informal observation is:
1- auto hold on
2- tranny to P
3- seat belt off
4- ignition off
Try that and see. Not sure if switching 3 and 4 matters.

But when it happens: BINGO!

Thanks Shadonoz. Will give it a shot. Curious though, what do you think the engineers’ logic was behind that sequence?

 

[shadonoz]

Here's what the OM says:

If any of the following conditions
occurs while the AUTOHOLD function
is operating (AUTOHOLD active
indicator light is turned on), the
electric parking brake (EPB) is applied
automatically and the AUTOHOLD
function turns off....
The ignition is switched OFF....

So maybe 2 & 3 are unnecessary.

 

[boandlkramer]

I like autohold.

I seem to have to engage it every time. Is that normal?

 

[Goguinness]

This is why I am keeping my 2015 Touring. I detest electric parking brakes.

 

[edbern]

Here's what the OM says:

If any of the following conditions
occurs while the AUTOHOLD function
is operating (AUTOHOLD active
indicator light is turned on), the
electric parking brake (EPB) is applied
automatically and the AUTOHOLD
function turns off....
The ignition is switched OFF....

So maybe 2 & 3 are unnecessary.

Definitely doesnt work with just auto hold alone. Ive tried that. Weather is bad here so I havent been out the car yet but will check your original four steps shortly

 

[edbern]

I like autohold.

I seem to have to engage it every time. Is that normal?

Yes thats normal. It defaults to off every time. I guess they want you to consciously decide to use it and not take it for granted.

 

[shadonoz]

Yes that’s normal. It defaults to off every time. I guess they want you to consciously decide to use it and not take it for granted.

+1
And so it won't be on if the driver doesn't expect it.
But I can't see what the harm would be to have it on all the time.

 

[Anchorman]

Safety regs dont allow that a brake that uses stored energy (pressure generated by the ABS pump) to be activated automatically. Its to remove the risk of a car running away if the pressure drops for some reason. The driver has to make a conscious decision to engage it at the start of every journey.

 

[edbern]

Definitely doesnt work with just auto hold alone. Ive tried that. Weather is bad here so I havent been out the car yet but will check your original four steps shortly

Turns out you were right and I was making it way too complicated. The reason is that my habit was to check if the brake was on *before* unbuckling or turning off the car, out of an abundance of caution. Since one of those has to happen for the great brake to engage, I was never going to see it.

To confirm: if auto hold is set and you either unbuckle or turn off the car (after engaging Park), it works every time.

So your steps 1 and 2 are both necessary, but either 3 or 4 will cause it to engage.

 

[shadonoz]

Safety regs don’t allow that a brake that uses stored energy (pressure generated by the ABS pump) to be activated automatically. It’s to remove the risk of a car running away if the pressure drops for some reason. The driver has to make a conscious decision to engage it at the start of every journey.

That makes sense as a general rule, but it's hard to see how the car would go out of control if autohold were to fail while functioning.

 

[Xeler8ing]

From the owners manual:

 

[boandlkramer]

Safety regs don’t allow that a brake that uses stored energy (pressure generated by the ABS pump) to be activated automatically. It’s to remove the risk of a car running away if the pressure drops for some reason. The driver has to make a conscious decision to engage it at the start of every journey.

Interesting. My ‘18 X3’s Autohold remembers my last setting. So it stays only time I disable it is in the automatic car washes.

 

[Xeler8ing]

Interesting. My ‘18 X3’s Autohold remembers my last setting. So it stays only time I disable it is in the automatic car washes.

Different regs for different countries perhaps (uhm)

 

[boandlkramer]

Different regs for different countries perhaps (uhm)

Both of my vehicles are US Specs.

 

[Xeler8ing]

Both of my vehicles are US Specs.

So USA allows it whilst EU doesn't and depends on whether the manufacturer enables the feature

 

[boandlkramer]

So USA allows it whilst EU doesn't and depends on whether the manufacturer enables the feature

It would be nice if coding was as easy for Mazda as it was for BMW.

 

[Xeler8ing]

It would be nice if coding was as easy for Mazda as it was for BMW.

One of the perks for BMW being a larger automotive brand with lots of $$$

 

[shadonoz]

Turns out you were right and I was making it way too complicated. The reason is that my habit was to check if the brake was on *before* unbuckling or turning off the car, out of an abundance of caution. Since one of those has to happen for the great brake to engage, I was never going to see it.

To confirm: if auto hold is set and you either unbuckle or turn off the car (after engaging Park), it works every time.

So your steps 1 and 2 are both necessary, but either 3 or 4 will cause it to engage.

I think I've got it figured out, Ed. There's one more factor we didn't include: autohold engagement [as opposed to just being turned on].

If I have autohold active, come to a stop, and remove my belt [which does seem to be the trigger], the EPB will engage if and only if autohold has engaged.

So if you have a light foot on the brake [like I do] and you ease to a stop not applying enough pressure to make HOLD light up on the gauges, the EPB will not engage automatically. But if you push hard enough to make autohold [and the light] activate, it will engage the EPB every time when you release the belt.

Try it and see if yours is the same.