Stability Control Function

[comp_engineer]

Hi Guys, I've been lurking on this site enviously looking at your builds and adventures for the last 15 months.
Our '13 TE is my wifes daily driver, so it'll be stock besides AT tires for a while as the extent of our off roading is dispersed camping on BLM land.

I drove the truck to work yesterday, which involves a small mountain pass with lots of turns. I was amazed at how intrusive the stability control is, it seemed to kick in before any noticeable loss of traction.
I know this is not a sports car, I get that, but I was suprised when the 'saftey feature' nearly put me off the road when it braked mid-corner.

My question for the group is if stability control applies the brakes when it senses loss of traction, or just by lateral G's? Seemed like it kicked in well before loss of traction.

After looking through what is customizeable, the threshold for stability control does not seem to be adjustable. Besides the obvious two suggestoins: don't drive your 4600lb BOF SUV like a corvette, or shut off traction control...anyone have any insight on what data the computer uses to apply stability control, and how I could make it less intrusive?

Thanks!

 

[Jeremy556]

Its based on tons of sensors, not adjustable, nor defeat able - even if you turn it off, it reactivates above a certain speed.

The fix for your problem is almost certainly a "zero point calibration." If you search for that you will find the procedure. Very common issue.

 

[1engineer]

Its based on tons of sensors, not adjustable, nor defeat able - even if you turn it off, it reactivates above a certain speed.

The fix for your problem is almost certainly a "zero point calibration." If you search for that you will find the procedure. Very common issue.

Exactly. Plus the wheels will brake independently of each other through ABS to keep you on your intended path. It uses wheel speed sensors, pitch, yaw, ABS and throttle control. Do the zero point calibration and you will be fine as it sounds like yours is just mixed up a little on what is what.

 

[mfregeau20]

And of course like you said, don't drive it like you stole it lol!

 

[jrob]

I had a zero point cal done and while it slightly alleviated the severity of the intrusion, it is still very much there. When I have time I'm going to try unplugging the yaw sensor or bypassing it somehow.
I'm sure this comment will probably draw scrutiny, but it is a terrible system. I honestly can't believe there is a "safety system" that will automatically apply brake mid turn with no driver input. It has pulled me out of several turns and I can honestly see it directly causing an accident. Once it kicks in, the brake stays applied until the truck "corrects" itself which sometimes leads to the truck coming almost to a stop. It used to just annoy me but it's to the point that I want to sell the truck every time it kicks in.

 

[cbreze]

I had to have the zero point cal done after a lift. This helped a lot, but it still will kick in on sharp turns even with no loss of traction. I think of this as a reminder to maybe slow down on my turns. These are heavy rigs and mine like some others are more top heavy than stock. So when I hear/feel it kick in I say to myself "maybe time to slow down around these turns".

 

[STLDAVE]

One time when I wasn't driving at all near the limits and had stability control kick in, I ended up in someone's driveway. Luckily there wasn't a tree or cliff there instead. The system sucks as far as I'm concerned.

 

[veloindy]

Mine kicks in when the front tires are slightly under inflated.

 

[1engineer]

I had a zero point cal done and while it slightly alleviated the severity of the intrusion, it is still very much there. When I have time I'm going to try unplugging the yaw sensor or bypassing it somehow.
I'm sure this comment will probably draw scrutiny, but it is a terrible system. I honestly can't believe there is a "safety system" that will automatically apply brake mid turn with no driver input. It has pulled me out of several turns and I can honestly see it directly causing an accident. Once it kicks in, the brake stays applied until the truck "corrects" itself which sometimes leads to the truck coming almost to a stop. It used to just annoy me but it's to the point that I want to sell the truck every time it kicks in.

How is it going to cause you an accident?
Why can't you believe it will apply the brakes?
Do you understand even basic physics?

One time when I wasn't driving at all near the limits and had stability control kick in, I ended up in someone's driveway. Luckily there wasn't a tree or cliff there instead. The system sucks as far as I'm concerned.

Why does it suck? I'm curious.

I have had this system now since 2011. It has been there through 3 tough winters and works exactly the same every time. Yes, I have to turn it off once in a great while (in very specific instances) but otherwise it works to keep me pointed in the direction of travel. Do you guys think this is a rally car and, get this, did you know race cars (even F1) have these systems?

 

[Jeremy556]

Here are some of the parameters it uses

I can say that when it is in need of calibration, it really does suck. On gentle turns it will cut power and apply the brakes mid turn, making you go outside of your intended line. When mine is calibrated, I can go around turns on the edge of the tires' limit without it interfering.

 

[1engineer]

Exactly. You should be able to go through a turn faster with VSC (stock tires, no lift, etc) on than without. Now if its lifted, bigger tires, etc then of course it won't handle perfectly because you have changed the parameters and I seriously doubt that any of us knows how to translate a 3" lift (changes CG) into sensor values or ECU code. But Zero Point Calibration makes it handle just fine because those values will just reach their preassigned values eventually.

 

[comp_engineer]

Thanks for the info guys.
I'll make up a jumper and do the zero cal.
I understand that a lift or other mods could effect the calibration.
Any idea why a stock truck with 14k miles would be off?
Thinking back, I may have been closer to the edge of my traction circle than I thought.

 

[BobsTrail]

I have to wonder if a sensor is bad and/or it just needs zero point calibration.

I have been on sand dunes aired down to 15 and many trails at 15 and 20. The VSC has only triggered a few times and it was appropriate for the conditions.

Last week I came down a mountain road (on-road) and was pushing the turns until my wife complained, the VSC never acitvated. She told me we are not in our sons CTS.

It's appears to be a good system on my 2013 Trail when all is working correctly.

Go ahead and flame me, I have been painting windows all day and it can't get any worse.

 

[Jeremy556]

I had a zero point cal done and while it slightly alleviated the severity of the intrusion, it is still very much there. When I have time I'm going to try unplugging the yaw sensor or bypassing it somehow.
I'm sure this comment will probably draw scrutiny, but it is a terrible system. I honestly can't believe there is a "safety system" that will automatically apply brake mid turn with no driver input. It has pulled me out of several turns and I can honestly see it directly causing an accident. Once it kicks in, the brake stays applied until the truck "corrects" itself which sometimes leads to the truck coming almost to a stop. It used to just annoy me but it's to the point that I want to sell the truck every time it kicks in.

I would grab a $30 cable from eBay and get techstream running. You can retrieve freeze frame data from previous times that VSC engaged, and watch/capture real time data as you drive around to establish a base line.

If it engages when the tires aren't howling, something is wrong.

 

[harper7]

I had a zero point cal done and while it slightly alleviated the severity of the intrusion, it is still very much there. When I have time I'm going to try unplugging the yaw sensor or bypassing it somehow.
I'm sure this comment will probably draw scrutiny, but it is a terrible system. I honestly can't believe there is a "safety system" that will automatically apply brake mid turn with no driver input. It has pulled me out of several turns and I can honestly see it directly causing an accident. Once it kicks in, the brake stays applied until the truck "corrects" itself which sometimes leads to the truck coming almost to a stop. It used to just annoy me but it's to the point that I want to sell the truck every time it kicks in.

Sounds like Zero point wasn't done correctly! The procedure is very finicky about following all the instructions to the letter or else it won't work.

Mine has only kicked in a few times ever! I know the TE's with KDSS have seemed to be a little more touchy but still should be nothing like you describe and needs calibrated to fix it. Unplugging the yaw sensor won't fix it!.....http://www.toyota-4runner.org/5th-g...celeration-sensor-zero-point-calibration.html

C'mon man!:lol:

 

[jrob]

I would grab a $30 cable from eBay and get techstream running. You can retrieve freeze frame data from previous times that VSC engaged, and watch/capture real time data as you drive around to establish a base line.

If it engages when the tires aren't howling, something is wrong.

Thanks, I've been meaning to pick one up. I didn't realize it could log VSC history with indivdual sensors, that would be very useful info for locating a faulty sensor for sure. It engages long before tires are even thinking about making noise. I agree something is probably wrong even after the cal I had done.

How is it going to cause you an accident?
Why can't you believe it will apply the brakes?
Do you understand even basic physics?

Why does it suck? I'm curious.

I have had this system now since 2011. It has been there through 3 tough winters and works exactly the same every time. Yes, I have to turn it off once in a great while (in very specific instances) but otherwise it works to keep me pointed in the direction of travel. Do you guys think this is a rally car and, get this, did you know race cars (even F1) have these systems?

Do you understand even basic driving?
Any amount of braking midturn will have an effect on vehicle trajectory, pulling you out of your line. The fact that a machine can interfere with driver input, and is not defeatable, is unbelievable to me. The machine has no way of knowing road conditions, environmental variables, cliff edges, walls, barriers, oncoming traffic. How does it know it's interference with driver input will not put the vehicle in further harms way? I have had drivers following me rather closely down a pass, and while taking a turn, at posted speed limit by the way, the system kicks in and my vehicle slows. I have noted once or twice the nose of the vehicle following me diving under braking directly due to this system applying brakes unnecessarily.

Dude, are you really trying to compare the traction control systems on a Formula 1 car to a Toyota 4runner...?

Sounds like Zero point wasn't done correctly! The procedure is very finicky about following all the instructions to the letter or else it won't work.

Mine has only kicked in a few times ever! I know the TE's with KDSS have seemed to be a little more touchy but still should be nothing like you describe and needs calibrated to fix it. Unplugging the yaw sensor won't fix it!.....http://www.toyota-4runner.org/5th-g...celeration-sensor-zero-point-calibration.html

C'mon man!:lol:

Well familiar with the thread Harper, thank you. I had the dealer perform the zero point cal when I went in for an oil change. The master tech that performed the cal gave me a run down, as it was not as straight forward as some have portrayed it to be, at least not the Techstream procedure when followed to the letter. It took him about 2 hours and re calibrated every sensor and system involved, ABS, wheel speed sensors, crawl, hill assist, etc.

I only mention trying to unplug the yaw rate sensor as that seems to be the input that is causing trouble. (techstream logging would be very useful here to determine that) The reason I think that, is if I am on a sweeping turn where the Gs are more gradually applied, it never kicks in and I can even accelerate out of apex with no issue. On the short "choppy" turns you find on mountain passes when there is a more rapid change in direction, the system will go ape shit 8 out of 10 turns at very reasonable speeds.

I'm fairly certain something is wrong with my system even after cal, and perhaps I need to look at individual sensors. I really just want it off, but I realize its not that easy.

 

[1engineer]

Do you understand even basic driving?
Any amount of braking midturn will have an effect on vehicle trajectory, pulling you out of your line. The fact that a machine can interfere with driver input, and is not defeatable, is unbelievable to me. The machine has no way of knowing road conditions, environmental variables, cliff edges, walls, barriers, oncoming traffic. How does it know it's interference with driver input will not put the vehicle in further harms way? I have had drivers following me rather closely down a pass, and while taking a turn, at posted speed limit by the way, the system kicks in and my vehicle slows. I have noted once or twice the nose of the vehicle following me diving under braking directly due to this system applying brakes unnecessarily.

Dude, are you really trying to compare the traction control systems on a Formula 1 car to a Toyota 4runner...?

Yes I think I understand driving (and definitely physics) better than you understand VSC, and yours must be broken. Your paragraph above is amazing:

"Any amount of braking midturn will have an effect on vehicle trajectory"
Yes and if I can brake each wheel at a different rate and r e t a r d the throttle I can bring that vehicle under control from a lot of situations much better than a vehicle without VSC.

"The fact that a machine can interfere with driver input, and is not defeatable, is unbelievable to me"
The "machine" is much better than you. It's quicker and especially smarter because it knows when you are getting ready to f something up and does something about it to keep the shiny side up. BTW our 4Runner is downright primitive compared to what's out there now. Radar based adaptive cruise control, blind spot avoidance, brake assistance, sonar for pedestrians, etc.

"The machine has no way of knowing road conditions, environmental variables, cliff edges, walls, barriers, oncoming traffic. How does it know it's interference with driver input will not put the vehicle in further harms way?"
Bro, think about what you just said here. How do any of these things matter? First, you are already in harm's way if it activates! If the VSC has been activated (normal VSC not your broke one apparently) you have pushed the vehicle into a hazardous situation that could be unrecoverable. I'm not talking about parking lot doughnuts on a cold winter night, I'm talking about that lady who is driving the 4Runner too fast because she has to get home to pick up her kid and starts sliding to the edge of a rain and oil slicked road along a ravine. Look, it does not normally kick in until you have messed up, unless again, you are playing in the snow or you have a screwed up VSC.

"I have had drivers following me rather closely down a pass, and while taking a turn, at posted speed limit by the way, the system kicks in and my vehicle slows. I have noted once or twice the nose of the vehicle following me diving under braking directly due to this system applying brakes unnecessarily."
Their fault for following too close. Not your problem.

"Dude, are you really trying to compare the traction control systems on a Formula 1 car to a Toyota 4runner...?"
Absolutely. It is very similar but the F1 has easy to tune parameters. Same concept and similar sensors.

It's obvious either you are Ken Block or your vehicle's VSC is messed up. Go to a dealer, take one similar to yours for a test drive and see.

Look, I know there are quirks even with a correctly operating VSC. For one, they can get confused. Example: Coasting into a slick snow and ice turn way too fast using no throttle or brakes. What's the VSC going to do? If you have no throttle it cannot cut the throttle. Example: If you go in too hard and deep into a turn (say 70 on a 25 turn) you can exceed the VSC's ability to save your ass. Example: Stopped going up a steep snow and ice covered hill. When you go to move forward and your tires start to slip, it will apply the brakes and r e t a r d the throttle and not allow you to spin a little to gain momentum. This is where I turn it off and why the switch is there.

Just in case you still don't understand, here are a few links for you to watch:
How Vehicle Stability Control (VSC) works - YouTube
VSC Explained - YouTube

Pay attention especially to the 2nd video and you can see that with a properly operating VSC system, you can in fact corner faster than a vehicle without this system. Good luck.

 

[bobdacat]

I had this happen once also taking a turn at speed, on a off ramp, driver side front tire applies braking, forcing vehicle to take a different trajectory, or going straight instead of continuing turn. I had control of vehicle, and didn't appreciate the computers help. That is the one problem I have with all this fancy computer crap. I am 45 and grew up learning how to control my vehicle with steering wheel and accelator and brake pedal. I wish you could turn it off as well but it just comes back on. I miss the old days when it was just a gear shift, clutch and then the transfer case shifter.

 

[cbreze]

I had this happen once also taking a turn at speed, on a off ramp, driver side front tire applies braking, forcing vehicle to take a different trajectory, or going straight instead of continuing turn. I had control of vehicle, and didn't appreciate the computers help. That is the one problem I have with all this fancy computer crap. I am 45 and grew up learning how to control my vehicle with steering wheel and accelator and brake pedal. I wish you could turn it off as well but it just comes back on. I miss the old days when it was just a gear shift, clutch and then the transfer case shifter.

I'm not wild about my 4runner taking control either. You're still young enough to see vehicles that drive themselves becoming mainstream, just a matter of time. Our big brother government needs to protect us from ourselves eh?:help:

It took me a while to get used to the stability control, but now I find it has actually changed my driving habits possibly for the better as far as not taking turns as fast as previously. I find going into a turn that if it doesn't kick in I've done a safe turn. When it does inevitably kick in once in a while tho if I back off the gas pedal it reverts back to my control. Been my experience so far anyway. This said, I could certainly live without this feature.

 

[jrob]

Yes I think I understand driving (and definitely physics) better than you understand VSC, and yours must be broken. Your paragraph above is amazing:

"Any amount of braking midturn will have an effect on vehicle trajectory"
Yes and if I can brake each wheel at a different rate and r e t a r d the throttle I can bring that vehicle under control from a lot of situations much better than a vehicle without VSC.

"The fact that a machine can interfere with driver input, and is not defeatable, is unbelievable to me"
The "machine" is much better than you. It's quicker and especially smarter because it knows when you are getting ready to f something up and does something about it to keep the shiny side up. BTW our 4Runner is downright primitive compared to what's out there now. Radar based adaptive cruise control, blind spot avoidance, brake assistance, sonar for pedestrians, etc.

"The machine has no way of knowing road conditions, environmental variables, cliff edges, walls, barriers, oncoming traffic. How does it know it's interference with driver input will not put the vehicle in further harms way?"
Bro, think about what you just said here. How do any of these things matter? First, you are already in harm's way if it activates! If the VSC has been activated (normal VSC not your broke one apparently) you have pushed the vehicle into a hazardous situation that could be unrecoverable. I'm not talking about parking lot doughnuts on a cold winter night, I'm talking about that lady who is driving the 4Runner too fast because she has to get home to pick up her kid and starts sliding to the edge of a rain and oil slicked road along a ravine. Look, it does not normally kick in until you have messed up, unless again, you are playing in the snow or you have a screwed up VSC.

"I have had drivers following me rather closely down a pass, and while taking a turn, at posted speed limit by the way, the system kicks in and my vehicle slows. I have noted once or twice the nose of the vehicle following me diving under braking directly due to this system applying brakes unnecessarily."
Their fault for following too close. Not your problem.

"Dude, are you really trying to compare the traction control systems on a Formula 1 car to a Toyota 4runner...?"
Absolutely. It is very similar but the F1 has easy to tune parameters. Same concept and similar sensors.

It's obvious either you are Ken Block or your vehicle's VSC is messed up. Go to a dealer, take one similar to yours for a test drive and see.

Look, I know there are quirks even with a correctly operating VSC. For one, they can get confused. Example: Coasting into a slick snow and ice turn way too fast using no throttle or brakes. What's the VSC going to do? If you have no throttle it cannot cut the throttle. Example: If you go in too hard and deep into a turn (say 70 on a 25 turn) you can exceed the VSC's ability to save your ass. Example: Stopped going up a steep snow and ice covered hill. When you go to move forward and your tires start to slip, it will apply the brakes and r e t a r d the throttle and not allow you to spin a little to gain momentum. This is where I turn it off and why the switch is there.

Just in case you still don't understand, here are a few links for you to watch:
How Vehicle Stability Control (VSC) works - YouTube
VSC Explained - YouTube

Pay attention especially to the 2nd video and you can see that with a properly operating VSC system, you can in fact corner faster than a vehicle without this system. Good luck.

Go get em internet cowboy!
Keep in mind that YOU started with the condescending attitude here bud. I stated my case against this VSC system as I have experienced it. Then I acknowledged the fact that mine is probably messed up. Your counter arguments reflect the opinions of a very self righteous typical engineer. Vast knowledge of many things with a functional understanding of very little.
VSC is a wonderful thing on paper.
So is communism. But that doesn't really work worth a **** either does it?
If you are seriously going to persist the systems on GP cars is similar to the mass produced system on an SUV you render your own argument invalid. Save your YouTube links bro.

How many autocrosses and track days have you been to by the way?

I'm not gonna polute this thread any further with argument. So in closing,

I like chocolate cake.