Automatic Emergency Breaking Front/Rear

The disc brakes are actuated mechanically, so I'd be curious how the brakes are held if that's the case. Some other system?

As far as engaging the system, you should be able to turn it on as soon as you start the vehicle, with your foot on the brake, and the parking brake has been disengaged.

This is the full list of conditions from the Mazda site:

When all of the following conditions are met, the AUTOHOLD operates and the brakes are held.

The ignition is switched ON (engine is running or stopped by i-stop).

The vehicle is stopped.

The brake pedal is being depressed.

The AUTOHOLD active indicator light turns on.

The accelerator pedal is not depressed.

The driver's seat belt is fastened.

The driver's door is closed.

There is no problem with the AUTOHOLD function.

The electric parking brake (EPB) is released.

There is no problem with the electric parking brake (EPB) function.

(Automatic transaxle vehicle)

The selector lever is in a position other than R position or the vehicle tilts forward with the selector lever in the R position.
 
I can't figure out how to engage the system. Do you have to turn it on before you start driving?

You should be able to push the button and see the light on the button any time you're driving, stopped or not. If it doesn't, see your dealer.
The disc brakes are actuated mechanically, so I'd be curious how the brakes are held if that's the case. Some other system?

It simply activates hydraulic pressure, exactly like stepping on the brakes. When you step on the gas, it releases.

[You mean the EPB is mechanical, don't you?]
 
Yeh, I just read the manual when this subject came up. All of those conditions are met when I pull up to a traffic light and try to turn it on. I've only tried it a couple of times when I first got the car. I'll have to get serious about it.

Regarding the mechanics of it...maybe an online repair manual could shed some light. I guess you saw that the Owner's Manual doesn't get into detail of how this works.
 
Here's some bedtime reading for you guys: Autohold
Compliments of our good friend Anchorman.
 
Thanks for the info. By mechanical, I meant physically (through brake fluid pressure, triggered by the master cylinder) rather than the EPB. I need to get ahold of these shop manual documents.
 
I will say this - there is one major downside to this. You might avoid a front end collision, but in my instance where it took over and braked for me (because the turd in front of me cut me off and slammed on his brakes), I had NO control over the braking and the car came to an ABRUPT stop. Had there been someone behind me not paying attention, they would have hit me.

However, I'd rather have to deal with a rear-end collision (in most cases unless its a truck or at highway speeds) than a front end one *I* caused.

I had kind of the same instance wasn't going very fast and car decided to go across my lane to turn, good thing I had my seat belt on or I would of probably hit the steering wheel hard. I was going to veer left and get by the car but the brake activated while I was swerving. All in all I am glad to have it.
 
I had kind of the same instance wasn't going very fast and car decided to go across my lane to turn, good thing I had my seat belt on or I would of probably hit the steering wheel hard. I was going to veer left and get by the car but the brake activated while I was swerving. All in all I am glad to have it.

I thought this was not supposed to engage if the system saw human interaction with the brakes, accelerator or steering wheel. Or am I thinking of something else?
 
Here's some bedtime reading for you guys: Autohold
Compliments of our good friend Anchorman.

Thanks to you and to Anchorman for the info.

I tried the Auto Hold again today, with the manual by my side, and [of course] it works fine. Not sure what was wrong before. I suspect I didn't have my foot on the brake long enough after turning it on at the red light for A.H. to engage.

I would use it all the time if I were still in DC traffic. It's a handy "anti-creep" feature...you can reach for the dropped cell phone worry-free.
 
I thought this was not supposed to engage if the system saw human interaction with the brakes, accelerator or steering wheel. Or am I thinking of something else?
That's my understanding as well, but it seems inconsistent with some of the other claims for/descriptions of it, and some of the stories we hear here.

Thanks to you and to Anchorman for the info.

I tried the Auto Hold again today, with the manual by my side, and [of course] it works fine. Not sure what was wrong before. I suspect I didn't have my foot on the brake long enough after turning it on at the red light for A.H. to engage.

I would use it all the time if I were still in DC traffic. It's a handy "anti-creep" feature...you can reach for the dropped cell phone worry-free.

You probably didn't apply enough pressure. It takes a small but distinct press on the brake pedal to invoke it after you've come to a complete stop. The time required of that pressure is "instant". That's nice because then you can apply LESS brake pressure than the threshold when you need to stop but might not want the brakes to hold, like when you drive up to a light that is just about to turn green.

It's perfect in town, irrelevant in the country. A great feature.
 
That's nice because then you can apply LESS brake pressure than the threshold when you need to stop but might not want the brakes to hold, like when you drive up to a light that is just about to turn green.

Funny, I engaged it 3-4 times, and one of those [inconveniently] was when the light was about to change.

Good to know about the brake pressure. I can see using A.H. when I go into the larger towns/cities around here. Since I've been here, Charlottesville at times has become as congested as Northern Virginia...not because of absolute volume, but because of relative capacity.

All this Drive-by-Wire opens up tons of feature options, huh?

edit to add: Regarding the Smart Braking, I commented that I had BRAKE! appear on my HUD (without braking) for no apparent reason one Sunday morning as I headed into a curve. Well, the manual cites the specific condition of heading into a curve where a fence is present (one was) as possibly triggering the system. I must have been doing just the right speed, because I go that way weekly and this happened that one time. Yet I've sometimes come up quickly on folks who are turning out of my way and had BRAKE! appear but not had the system engage under those conditions as others report.

It's had to pick apart because we're not testing in controlled conditions, we're cobbling memories after the fact.
 
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I thought this was not supposed to engage if the system saw human interaction with the brakes, accelerator or steering wheel. Or am I thinking of something else?
I hadn't hit the brake yet as I was going to steer around, maybe it happened prior to me moving the steering wheel, but my hands were on the wheel.
 
Anyway, I'm still unclear if it would of braked or not. I'm not taking the chance.

Oh trust me...you'll know, it's crystal clear, and you'd better be ready for it. It's a full on 'slam the brakes', pedal to the floor, ABS activation, the whole works. Likely screwed up my drivetrain as I was not at all in a braking posture. Two weeks into owning the thing and I was almost rear-ended by a Jeep while passing a buggy (a maneuver so mundane around here it's like taking a breath). The automotive software systems 'engineers' (loose term), apparently didn't take into account local driving styles. The what-ifs of programming...it's a perfect world ya know. Like our driving style around here regarding buggies in the road. The brakes slammed on hard same time as the warning (it's setting was as low as it can go). Full slam, full stop. My hand was resting on the shifter which then was pushed forward into neutral, because, well, I wasn't expecting the stupid car to slam the brakes (that's the be ready part). Now I have zero forward drive power to get out of the way of the Jeep following me (extremely pissed off evidenced by the horn and screeching tires) because he wasn't expecting "me" to pull a stupid, bone-headed stunt like coming to a complete stop while performing the common everyday maneuver of rounding a buggy. Nice huh? How's that for 'safety'?? Absolutely hate all of this annoying half-azzed and over-complicated automation chit in vehicles that can't be disabled. But hey, no heated side mirrors in a $30k+ AWD vehicle in the Northeast U.S. right? Makes perfect sense.
 
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It's a good tool to assist you if it detects the possibility of an impact with the vehicle in front of you, given your speed and distance to that vehicle. I've had it pop up twice on my CX5, both times when there was a slow turning vehicle in front of me.
 
This particular PITA (almost quite literally for the CX5's hind quarters several times now) is, most definitely, not a tool...one can choose to select and use a tool, or, leave it in the drawer. I can't choose NOT to use this this particular annoyance the same way I can choose to not use lane keep assist or radar assist cruise control. Great idea, in theory. However, as is the case all too often anymore with vehicle automation, very poorly planned and implemented. It is, however, an excellent, over-complicated, high-priced, nanny-minder feature for people who like to sit behind the wheel and do everything else BUT drive the vehicle. Still want some heated side mirrors...now those are excellent tools to have in the part of the country where I commute.
 
I thought this could be turned off through the accessories settings (although it automatically turns back on each time you start the car).

Do I misunderstand?
 
@Avoidin Deer...digging your screen name right about now. Negative. Sensitivity can be changed (and it remains where it's set from one driving cycle to the next), but, the 'feature' can not be completely disabled...at least on my 2018. Dealer has no way of completely disabling it either because...it's supposedly a "safety" feature...least that's the line I was fed when I demanded it to be shut off last visit. I'm certain there's probably a way to do so, but they can't per Mazda for perceived liability reasons. I stated in my service order that this so-called "safety feature" nearly caused me to be rear-ended several times. They, dealer and Mazda both, could have cared less. I get rear-ended because of this "safety feature" and I'll send them both the bill. Been driving like I drive for 40+ years and never ran into anything (on 4-wheel drum brakes long before ABS), nor, have ever been rear-ended. I get this safety-laden techno-marvel and I've nearly been rear-ended three times and it's braked on its own for stupid reasons many times. The automation needs to learn how I drive and not the other way around.
 
This particular PITA (almost quite literally for the CX5's hind quarters several times now) is, most definitely, not a tool...one can choose to select and use a tool, or, leave it in the drawer. I can't choose NOT to use this this particular annoyance the same way I can choose to not use lane keep assist or radar assist cruise control. Great idea, in theory. However, as is the case all too often anymore with vehicle automation, very poorly planned and implemented. It is, however, an excellent, over-complicated, high-priced, nanny-minder feature for people who like to sit behind the wheel and do everything else BUT drive the vehicle. Still want some heated side mirrors...now those are excellent tools to have in the part of the country where I commute.

Have you considered disconnecting the physical lead to the radar? Don't know if it would work, would likely generate a constant error message, but might suit your purposes better.
 
@Avoidin Deer...digging your screen name right about now. Negative. Sensitivity can be changed (and it remains where it's set from one driving cycle to the next), but, the 'feature' can not be completely disabled...at least on my 2018. Dealer has no way of completely disabling it either because...it's supposedly a "safety" feature...least that's the line I was fed when I demanded it to be shut off last visit. I'm certain there's probably a way to do so, but they can't per Mazda for perceived liability reasons. I stated in my service order that this so-called "safety feature" nearly caused me to be rear-ended several times. They, dealer and Mazda both, could have cared less. I get rear-ended because of this "safety feature" and I'll send them both the bill. Been driving like I drive for 40+ years and never ran into anything (on 4-wheel drum brakes long before ABS), nor, have ever been rear-ended. I get this safety-laden techno-marvel and I've nearly been rear-ended three times and it's braked on its own for stupid reasons many times. The automation needs to learn how I drive and not the other way around.

Systems like this are meant to prevent the close calls you seem to have been putting yourself in for the past 40+ years. It's great that you've never had any issues (up until now), but it sounds like you're pulling out from behind the buggy way too late (or coming up on it too fast). I drive pretty aggressively in my CX-9 sometimes, and I've had to maneuver from behind a semi truck while accelerating to get out of the way of an emergency vehicle behind me. The "Brake!" warning has come up in situations like that, but it hasn't braked for me, and I felt that I was cutting it VERY close.

Maybe you should adjust your driving style a little bit to accommodate the warning system. If not, you should find a different, older car (not a new one, because a new one will have AEB and will likely perform the same way that Mazda's system does). I don't think you'll have any chance of winning this in court if your argument is "I've been driving the way that I do for 40+ years, the system is flawed".
 
From my 2019 CX-5 Owner's Manual on the Smart Braking System (SBS).

Pg 4-174:
In the following cases, turn the system off to prevent a mis-operation:

-The vehicle is being towed or when towing another vehicle.
-The vehicle is on a chassis roller.
-When driving on rough roads such as in areas of dense grass or off-road.

The SBS system operates when all of the following conditions are met:
The ignition is switched ON.
The SBS system is on.
The vehicle speed is about 15 km/h or faster (10 mph or faster).
The relative speed between your vehicle and the vehicle ahead is about 15 km/h or faster (10 mph or faster).
The Dynamic Stability Control (DSC) is not operating.

Pg. 4-175:
Stopping The Smart Brake Support (SBS) System Operation

The SBS system can be temporarily deactivated. Refer to Personalization Features on page 9-12. When the SBS system is turned off, the SBS OFF indicator light turns on. When the engine is restarted, the system becomes operational. NOTE If the SBS system operation is turned off, the Smart City Brake Support (SCBS) system operation is turned off simultaneously.

Pg 4-172:
Says you can separately turn off the Smart City Brake Support system.

Pg. 4-28:
SBS%20Off%20manual%20page.png


Funny how in 2019 you can shut the thing down. There's gotta be a reason, huh?
 
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