Scary moment this morning in the T4R

[Riser]

So I'm coming to a stop, on a road from my house, towards the local highway. I touch the brakes from 35mph and the brakes lock up! My truck goes sideways towards the highway, beeps like crazy (about to rollover?) and then kicks back around. I did a 180, but I really thought I was going to rollover and end up in the highway. I can say in nearly 20 years of driving, this has never happened! There was light snow on the ground but I didn't see any ice......

I can only think of one thing: The initial aggressive "grab" the T4R brakes have, could have caused the lockup. This combined with the fact that the braking zone is downhill, and there was light snow, makes sense to me. But this truck does seem to use ABS more than other vehicles I have driven. Even in the dry. Thank god my family was not in the car with me.

I have over 5 years of road racing under my belt too on various tracks thought the US. Not saying I was the fastest guy racing, but I know how to handle a vehicle better than your average driver

 

[Hawkdog21]

So I'm coming to a stop, on a road from my house, towards the local highway. I touch the brakes from 35mph and the brakes lock up! My truck goes sideways towards the highway, beeps like crazy (about to rollover?) and then kicks back around. I did a 180, but I really thought I was going to rollover and end up in the highway. I can say in nearly 20 years of driving, this has never happened! There was light snow on the ground but I didn't see any ice......

I can only think of one thing: The initial aggressive "grab" the T4R brakes have, could have caused the lockup. This combined with the fact that the braking zone is downhill, makes sense to me. But this truck does seem to use ABS more than other vehicles I have driven. Thank god my family was not in the car with me.

I have over 5 years of road racing under my belt too on various tracks thought the US. Not saying I was the fastest guy racing, but I know how to handle a vehicle if it breaks loose.......

was your gas cap on all the way?

jk, thank god you are alright and got out of that safely. I have had 4runners in the past that have decided to engage ABS in situations that were no different than normal driving leading me to almost crash into things, so who knows. Again, glad your safe, who knows what was going on in the 4runners brain. I sometimes question wether the brake assist is needed, if i quickly slam on the brakes, I can slam on the brakes, id rather make the decision myself rather than a computer...

 

[gwcpa]

I had the brake assist kick in within the first 100 miles of ownership. Deer appeared on the side of a dark road, so I hit the brakes in case they decided to cross. The brake assist "decided" I needed to stop faster!

There were 5 of us and the other 4 (3 kids) and my wife was like "you didn't have to brake that much!"

It actually made me get off the brakes sooner than I would have normally.

 

[CApilot78]

Brake Assist

NHTSA did a study on brake assist, and found that the percentage of accidents it helps prevent are is statistically insignificant.

Also, it works better on some cars then others, and I think 4runner falls into the "others" category. They found the 4runner actually had a greater stopping distance with the brake assist then a human giving maximum pedal force. But when a human didn't give max pedal force, the BA stopped quicker.

Given that i know better than a computer how quickly I want to stop, I am NOT A FAN of brake assist. It was designed for people afraid/reluctant to give maximum pedal force when it is necessary, the problem is, unless the computer has eyes, it doesn't see what I see.

Can it be disabled?

http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash Avoidance/Technical Publications/2010/811371.pdf

 

[gwcpa]

Mine hit so hard it chirped the tires running about 55 mph. TMC has probably cranked up all the settings since the U-A claims. I don't like it.

Unintended consequences to follow, I'll brake less aggressively in the future since I can't tell what the heck me truck is going to do.

 

[westwind77]

I am not a fan of how aggressive and touchy the brake assist is, that being said I can see how it could help prevent or lessen a very serious accident.

I would say I trip mine once a month, I have learned not to keep anything sitting in the front seat as it gets ejected onto the floor.

Sounds like you hit some sheet black ice for your truck to spin sideways! I have TRIED to spin my 4R in the snow/slush and the VSC using the ABS will not allow it. The VSC does an excellent job keeping the 4R straight but no system can work effectively on ice, unless you are driving a Zamboni. Glad to hear you are ok!

 

[Superman]

You have to keep in mind that this technology supports the needs of your novice and average driver. We don't favor it on this forum because almost all of us are seasoned drivers that could steer out of trouble or apply brakes with enough force if needed. There are only 10% of us out there, remaining 90% of drivers fail to brake with enough force in emergency situations, according to research conducted by Mercedes-Benz. In 2007 the European Commission wanted Brake Assist to be included on all new models sold in the EU as standard by 2009. :lookout:

"Brake Assist detects circumstances in which emergency braking is required by measuring the speed with which the brake pedal is depressed. Some systems additionally take into account the rapidity of which the gas pedal is released, pre-tensioning the brakes when a "panic release" of the gas is noted. When panic braking is detected, the Brake Assist system automatically develops maximum brake boost in order to mitigate a drivers tendency to brake without enough force. In doing so, Brake Assist has been shown to reduce stopping distance by a significant margin; up to 20% in some studies."

 

[scanny]

That's strange, I recently had a trip to Vermont and roads there was snow covered and quite slipery and hilly with speed limit 50 mph. I expected VSC/TRACK to kick in all the time but it beeped just once in a whole week when I was going over a hill. yesterday we got about 2 inches of snow, On empty roads I managed truck to slip a little bit, but it was not easy and VSC/TRACk never kicked in. ABS worked fine, but I didn't feel any brake assistance. So I still can't understand VSC/TRACK logic, it doesn't seem to work for me, but 4Runner seems to be pretty stable on show. Guess need some more experience to figure how it works.

 

[adoihcj]

Glad to hear you are okay. I guess I never really thought about what would happen if brake assist kicked in on a slippery road and VSC doesn't correct it. Thanks for putting this on my radar.

Like others there, I do not like it. I chirped the tires going from the gas to the brakes quickly and my wife was yelling at me for stopping so hard. I told her it was the 4R not me. If someone was behind me when I stopped like that, I'd be needing a new rear end and the car behind me would have been totaled. I understand why they have it, but I'd like to have more control.

 

[westwind77]

I guess I never really thought about what would happen if brake assist kicked in on a slippery road and VSC doesn't correct it.

In my experience/opinion there would have to be a decent amount of ice, or you are driving too fast for the conditions, for VSC not to correct the 4R. Like I said I have spent a good amount of time in the snow in big empty parking lots trying to get it to spin with no luck, yet (which is a good thing). VSC is never going to be 100%, but if you are driving safe for the conditions and not on an ice skating rink, I would not be overly worried about it.

 

[Riser]

thanks guys.

My wife ALWAYS complains about my braking, since we have purchased the T4R. I will say it drives excellently in snow and other conditions and it is all around a great vehicle. I have lost a little faith in the brakes now though. It feels like the brakes are either ON or OFF. There is no gradual/linear feel if you get my drift. I guess I will leave a lot more room next time I have to brake in the snow. I wish they could scale back the aggressiveness of the brake assist though, I really do. My '97 Ford Expedition felt better braking in last year's blizzard.

 

[CApilot78]

thanks guys.

My wife ALWAYS complains about my braking, since we have purchased the T4R. I will say it drives excellently in snow and other conditions and it is all around a great vehicle. I have lost a little faith in the brakes now though. It feels like the brakes are either ON or OFF. There is no gradual/linear feel if you get my drift. I guess I will leave a lot more room next time I have to brake in the snow. I wish they could scale back the aggressiveness of the brake assist though, I really do. My '97 Ford Expedition felt better braking in last year's blizzard.

As soon as someone crashes, etc. do to the brake assist, this will become more than a discussion. The NHTSA report didn't give the 4runner BA good reviews.

 

[SeattleMike]

I don't usually have a problem driving and braking in any weather. Last week we were driving down a highway and the guy in front of us jammed on his brakes to avoid a dog. I had plenty of space to slow down, but I let off the gas so fast and tapped the brakes so quickly that the BA kicked in and scared the **** out of my wife. I think it's probably a good bet that a road racer is going to have better than average reflexes on the pedals and trigger the system by accident just driving naturally. Hopefully, Toyota addresses the problem before they get sued by some insurance company tired of paying out "rear-ender" claims.

 

[1000MPH]

I don't think I've had brake assist kick in yet but i did have an annoying experience with the "auto engine braking/tranny downshift thingy". I was doing some hard braking on a mtn road and had the trans downshift to help in the braking (I've had this before so it doesn't surprise me anymore), but it wouldn't upshift when I exited the corner and accelerated . It's the highest I've revved the motor so far. It didn't shift until I had almost come to a complete stop. Luckily it was a very quiet road. Served as a reminder to use the sport setting on mtn roads.

 

[scanny]

It's good to hear that you guys all ok, I'd be scared if it happened to me. I guess I'll try to activate brake assist on some empty road when it's safe to do so just to see how it works. In the meantime I'm glad I'm reading this forum, at least I will be prepared if something like this happens with me. Maybe it worth a try to write to Toyota about it and see what they say.

 

[4Robber]

35MPH and sideways? Had to be ice, no?

 

[Quentin]

35MPH and sideways? Had to be ice, no?

Sometimes the road is a lot slicker than you'd expect based on how sudden the weather change came or if they put gravel or lots of salt down. If the OP stabbed the brakes and was on slicker pavement than the thought, it is fully possible that he just went past the limit of traction and round the back came. With slick conditions, abrupt accel or decel gets you in trouble.

I was coming back from my parents' house one day in my Impreza driving like I normally do through the mountains. Basically just a hair over the posted signs for the turns, weather was nice. All of a sudden, I found the car facing 180º of where I should be. Rain must have come through that morning and brought up some oil and that was enough for the rear end to lose traction. My wife was in total shock because I wasn't driving hard, at all, for the conditions, so we thought.

 

[Snooperstyle]

BA has scared the pants off of me twice now, and has bothered me mildly a whole bunch of other times. One time I was in traffic that suddenly stopped, and I had a very full load and was top heavy with boats on the roof. My brakes locked up causing a skid on dry pavement. Where the heck were the ABS brakes during that moment? The 4runner's nose diving just makes it seem worse too. I am not a tailgater, and therefore don't normally have to switch from accelerator to brakes that quickly. Dare I mention the embarrassment of looking like I was more out of control than I was??

Just to add another opinion on here, I feel that the brake assist could easily put someone in danger, and that it is highly irritating. Sure would be nice to be able to turn it off forever.

 

[mag10]

Are we sure there is no way to turn this feature off?

 

[Ryan F.]

NHTSA did a study on brake assist, and found that the percentage of accidents it helps prevent are is statistically insignificant.

Also, it works better on some cars then others, and I think 4runner falls into the "others" category. They found the 4runner actually had a greater stopping distance with the brake assist then a human giving maximum pedal force. But when a human didn't give max pedal force, the BA stopped quicker.

Given that i know better than a computer how quickly I want to stop, I am NOT A FAN of brake assist. It was designed for people afraid/reluctant to give maximum pedal force when it is necessary, the problem is, unless the computer has eyes, it doesn't see what I see.

Can it be disabled?

How many accidents has brake assist prevented? Nobody knows. Know why? Because most people don't call the freakin' NTHSA to report their ass getting saved. Even if they did, nobody could point to the technology that saved it. The NTHSA records keeps track of how vehicles which got into a crash were equipped, and does stupid non-real world studies on such things. Why the hell didn't the NTHSA recommend ABS and air bags on all cars when these technologies came out? They couldn't conclude that it saved lives. The NTHSA is a joke...on yeah, they were all over that gas pedal thing. Turned out to be nothing. How much money did our Government waste on that?