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2021 Yaris emergency braking issue


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My wife's Yaris had the radar recall in April.

Since then she's had two issues where it has triggered incorrectly.

Today it brought her to an emergency stop because of a bicycle in a side street.

Is anyone else seeing any issues?  I'll have to take the car back to the dealer if it keeps happening, cos it's dangerous.

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Yes,

Twice since ownership both before the recall. A motorcycle coming slowly to a stop to give way to us on an open crossroads on our left as we approached and the car went to an emergency stop. Lucky there was no one behind. Can't remember the other circumstances. Nothing short of dangerous. However we have done about 5K since with no more episodes. However I expect it to happen again. 

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I have also experienced similar events where the car is just a little bit too eager to apply the brakes when it is not really necessary. Personally I blame the radar which is not focused enough (taking account of the vehicle's trajectory and also the angle of the front wheels) and judges the situation poorly at times. When it has started to happen to me, I have forcefully overridden it by simply depressing the accelerator pedal more; which seems to work fairly quickly and helps "it" to re-assess the situation. (in other words, I have never allowed the vehicle to complete its possible "emergency stop" type procedure)

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I think you might be disappointed after getting the check done because they’re looking for whether it works or not, not how it works.  These systems are not infallible and it’s impossible for them to take every possibility into account.  What they do succeed at is reacting to circumstances that thousands of people a year fail to do because they’re not paying proper attention or otherwise distracted and it ends with someone getting hurt.   It’s not that our humble Yaris’s have a cheap and cheerful system either.  I was driving a brand new 2022 top spec Lexus recently when a car approached quite abruptly from a side road and the Lexus welded itself to the road. It wasn’t a nice comfy stop, it was a retina detaching affair.  It surprised me and my daughter who was in the car with me but if that car hadn’t stopped, it would have avoided a collision.  I remember thinking “glad there was nobody behind” but then we always look for reasons why it’s a bad idea and not that it did exactly what it was designed to do.   Going back to our humble Yaris, it has a heater inside that enclosure behind the mirror to avoid the glass in there steaming up.  A lot of high end cars don’t.  

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The trick is to make sure the car behind you is another Mk4 Yaris :laugh: 

But yeah, the emergency auto systems are really not calibrated well for city driving. I have a feeling they were set up with Japanese roads and drivers in mind. I regularly have to slalom through very narrow streets with cars parked on the side of the road and random islands and regularly get the BRAKE!!!! warning come up, although it's rare for it to actually auto-brake - Have had it happen maybe 1 in 30 times vs the BRAKE!!!!!!!!!111!1!1!1 message popping up (It's extra scary if you have a HUD too as it flashes up right in front of you in a big red box! :eek: ). The auto-braking is really nasty tho; It's almost like hitting a wall it stops so hard! But I'm better at understanding it and anticipating situations that might trigger it allowing me to avoid them in the first place. (Mostly comes down to leave a bigger gap, brake earlier, accelerate later and drive slower :laugh: )

It's still not as bad as the other problem I have, where if turning right from the bottom of a T-junction to follow a car that's just passed left to right, the car will just cut power and leave me hanging across both lanes for a few seconds before deciding it's safe and letting you have the accelerator back, meanwhile there're cars flying at you from both directions! :eek: 

It still happens when I'm not thinking about it, but I find if I use less than half-throttle to move off (as opposed to flooring it) it usually doesn't trigger, and also giving the passing car a half-second head-start rather than trying to latch onto it as it passes also greatly lessens the probability of it cutting power mid-turn.

 

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On 5/20/2022 at 9:20 PM, Cyker said:

The trick is to make sure the car behind you is another Mk4 Yaris :laugh: 

But yeah, the emergency auto systems are really not calibrated well for city driving. I have a feeling they were set up with Japanese roads and drivers in mind. I regularly have to slalom through very narrow streets with cars parked on the side of the road and random islands and regularly get the BRAKE!!!! warning come up, although it's rare for it to actually auto-brake - Have had it happen maybe 1 in 30 times vs the BRAKE!!!!!!!!!111!1!1!1 message popping up (It's extra scary if you have a HUD too as it flashes up right in front of you in a big red box! :eek: ). The auto-braking is really nasty tho; It's almost like hitting a wall it stops so hard! But I'm better at understanding it and anticipating situations that might trigger it allowing me to avoid them in the first place. (Mostly comes down to leave a bigger gap, brake earlier, accelerate later and drive slower :laugh: )

It's still not as bad as the other problem I have, where if turning right from the bottom of a T-junction to follow a car that's just passed left to right, the car will just cut power and leave me hanging across both lanes for a few seconds before deciding it's safe and letting you have the accelerator back, meanwhile there're cars flying at you from both directions! :eek: 

It still happens when I'm not thinking about it, but I find if I use less than half-throttle to move off (as opposed to flooring it) it usually doesn't trigger, and also giving the passing car a half-second head-start rather than trying to latch onto it as it passes also greatly lessens the probability of it cutting power mid-turn.

 

I think you have hit the nail on the head. If when pulling out you are having to floor the accelerator you are probably taking too much of a risk. I tend to be gentle with the accelerator and have not had that particular problem. 

I have had the 'Brake!' warning plenty of times. It often happens when approaching a right hand bend where cars are parked on the bend. It drives me demented at times but I have not had the emergency brake activated - yet!

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It's not that I *have* to floor the accelerator, I just try and match the speed of the car that's passed as soon as possible so I'm keeping pace with traffic and avoid anyone following from having to slow down.

It absolutely hate it when people pull out of a junction into a road and dawdle, forcing everyone to brake and slow down while they apparently figure out how to get to 2nd gear or something.

Even if there is nobody following said car I will still try to get up to pace as soon as possible as I feel that is the safest thing to do. I've always believed the biggest cause of road accidents is not speed, but differences in speed; e.g. if everyone was driving at 70, that is much safer than some people driving at 20 and some at 40, so I try to keep pace whenever possible and minimize big speed changes when in traffic! (The latter also saves a lot of fuel!)

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2 hours ago, Cyker said:

people pull out of a junction into a road and dawdle,

Some of those cases are the car itself. With tight emission controls, start-stop systems, ABS and traction control it's very easy to find the car not actually going as hoped.

Our non-Yaris has start-stop and we always turn it off after starting (it's not 'sticky') as it's a nightmare.

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I think the system works quite well.  Yes I see the warning under certain conditions but it’s never intervened.  That’s exactly what it’s supposed to do - warn you of a potential threat and only intervene if the driver doesn’t react.  What triggered it on the Lexus was the speed a dope was approaching a junction from the side too fast, I don’t know why she would drive like that but the car protected me from her not stopping.  As for disabling auto stop, it’s surprising how many do it but I don’t think it should be an option, the cars with it only met homologation by having it so having a button to disable it is a farce.  You hear all sorts of rubbish about wearing batteries and starters like the designers hadn’t thought of it.

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21 hours ago, Cyker said:

It absolutely hate it when people pull out of a junction into a road and dawdle, forcing everyone to brake and slow down while they apparently figure out how to get to 2nd gear or something.

I was "guilty" of that more than once.:ph34r: Stupid MMT tansmission, E mode, refusing to change up from 1st gear.

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Not sure if PCS is adjustable on Yaris, it is on Corolla, there are three settings, default is the middle setting. Some of the most common accidents are people/cars/bikes stepping off the pavement or pulling out of side junctions and lane departures, hence why these form part of the PCS system. The car has braked for me in the past, but I never felt the car out of control or braked too hard for me

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Part of the reason I'm unwilling to change the settings or turn it off is it *has* saved me from 2 minor collisions so far and even tho' the false positives vastly outweigh the real positives it's still done its job, so I'm loath to turn it off.

TBH the only reason it gets so many false positives is it just isn't set up for tight city driving, but tweaking it for those sorts of margins would likely prevent the system from doing its job as it can't know what the intent of the driver is (BRAKE! "Yes I know I'm heading on a collision course for that parked car but trust me I'm going to curve round it as soon as I clear the island that your radar can't see!" BRAKE! "Goddamnit")

 

8 hours ago, mrpj1 said:

I was "guilty" of that more than once.:ph34r: Stupid MMT tansmission, E mode, refusing to change up from 1st gear.

I am trying to be more understanding, esp. now that I have been guilty of the same thing due to the safety system!! :laugh: (This is one reason I'd still rather drive a manual but those days are well past us now as we head to EV-only!)

If I could just disable the forward-cross traffic detection or whatever it is that is cutting input from the accelerator in that T-junction scenario, without disabling the whole system, that's all I would want TBH.

 

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6 hours ago, Cyker said:

This is one reason I'd still rather drive a manual but those days are well past us now as we head to EV-only!

As we head to autonomous vehicles ...

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Well we're 99% of the way there, it's just the 1% of impossible corner cases that they'll never be able to account for in software until we invent Skynet, but TBH I can't see it happening without a major shift in how liability works as that is the biggest barrier to fully autonomous transport at the moment.

 

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  • 2 weeks later...

Happened to me today - has the BRAKE! warning a couple of times over the last year, but today it full on emergency stopped… for a pedestrian walking round a corner to our left, onto our road, but still very much on the pavement.  Luckily the car behind me must have been on the ball as was on a 40mph road 😳

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I'd need to read the book again to be sure, but doesn't pressing the brake deactivate the auto brake (only for that event tho)?

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I don't know, I haven't found a way to override it other than stopping and letting it reset or steering so the car doesn't think you will crash any more.

I had the brake warning continually sound for about 5 long seconds the other day as I was slowing behind a sort of horrible SUV that had stopped ahead of me. I was constantly having to explain to passengers what the scary beeps mean, and now they know what it is, every time it happens they're like, "Seriously? Seriously?? That car's 10 metres away and we'e barely moving!!" and I'm like "Yup..."

 

 

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