VSC and Traction Control both de-throttle engine..

[JB.]

..apparently. For a long time I thought it was only VSC which limited engine output, but the STAR demonstaration for Traction Control at this link clearly states that it limits engine output.

People have been corrected many times, sometimes by me, about it being VSC that limits engine output rather than Traction Control but I guess that's not the case. What purpose, then, does the '08 VSC off switch serve when Traction Control is still able to de-throttle the engine?

Anyone have a clearer picture of this than I do? Is it perhaps that Traction Control de-throttles only on 2WD vehicles? I dunno.

http://www.toyota.com/vehicles/2008/4runner/key_features/star_safety_system.html

 

[Thai]

I am not sure, but when i saw the video and click on TRAC, there was no mention of dethrottling. When i had my '02 4runner, i never felt that the engine was limited when i spun in 4-LO (which is what i was in most of the time off-road). I do know that my wife's Highlander does indeed dethrottle when the wheel(s) are slipping while going straight.

 

[JB.]

I am not sure, but when i saw the video and click on TRAC, there was no mention of dethrottling.

De-throttling may not have been the best choice of words, but here is the line from the demo that occurs about 3/4 of the way through.

"...first, Traction Control would limit engine output and apply brakes to the spinning wheel.."

 

[Thai]

De-throttling may not have been the best choice of words, but here is the line from the demo that occurs about 3/4 of the way through.

"...first, Traction Control would limit engine output and apply brakes to the spinning wheel.."

Whoops, i may have missed it because i am using work computer with shitty speakers. I would imagine that it does limit all-out throttling to prevent damage to or overheating the brakes at a rapid rate. Given that the new Land Cruiser can maintain ATRAC continuously for 12 minutes (a feat apparently), i would imagine that the ATRAC computer would limit how high you can throttle the engine. Whatever that limit is, i never felt it when i was off-roading with my '02 4runner in 4-LO. Have you, JB??

 

[JB.]

Whoops, i may have missed it because i am using work computer with shitty speakers. I would imagine that it does limit all-out throttling to prevent damage to or overheating the brakes at a rapid rate. Given that the new Land Cruiser can maintain ATRAC continuously for 12 minutes (a feat apparently), i would imagine that the ATRAC computer would limit how high you can throttle the engine. Whatever that limit is, i never felt it when i was off-roading with my '02 4runner in 4-LO. Have you, JB??

No, can't say I have.

I wonder if there's not some inconsistency in Toyota's usage of the terms causing the confusion as I still feel I have a clear idea of how the systems work in various conditions, though my experience with the center locked in high range in slick conditions is limited. Snow is pretty scarce where I live, otherwise it would be pretty easy to test. Others, as I'm sure you've read, report turning off VSC to defeat the "snow lag" in traffic that some don't like and that vehicle behavior is consistent with my experience.

Perhaps I'm reading too much into the phrase "limit engine output" which might simply mean you can't rev it really high. There is obviously a big difference in the throttle response with VSC on vs off in super slick conditions.

 

[Falls]

The VSC will cut power , the Atrac will keep the power and use the pulsation of brakes to get all 4 wheels to get traction.

I was surprised at the 12 min. that Thai mentioned on the new LC . I've personally been stuck on a hill of snow with about 15 inches ( belly dragging) snow under the 4R . I was pushing the Atrac for a heck of a lot longer ( I would bet a half our) than that trying to get out and through all of it . It worked well all 4 tire were flinging snow and you can give it plenty of gas to over ride it to an extent. It would be nice with out all the beeping noise though.

 

[Thai]

It would be nice with out all the beeping noise though.

There's beeping?? On my 4runner, you hear strange 'doin' noises...like a spring coil being pulled apart and coming back. No beeping that i could remember.

Has that change in the 4th gen 4runner?

 

[Falls]

There's beeping?? On my 4runner, you hear strange 'doin' noises...like a spring coil being pulled apart and coming back. No beeping that i could remember.

Has that change in the 4th gen 4runner?

I'm sorry I think its the VSC that beeps at you. The Atrac make a noise of the brakes pulsating ( kind of a noise racket ) .

 

[toto]

Both share the same dashboard light - that "slippery when wet" icon. If either VSC or TRAC comes on, that light comes on.

The VSC also beeps at you if it starts doing its thing.
The first time you hear it, it's pretty alarming because it reminds you of those airplane crash movies... the beeping should be accompanied by a poorly-recorded voice that says "Pull Up! Pull Up!"

The TRAC does its thing silently except for the mechanical noises.

 

[Falls]

I wonder if there is a little beeper you can pull out so just the dash lights flash ?

 

[DiskDoctr]

Can cause problems...

Just to let you know...

The traction control/anti-skid program allows ZERO throttle application when it kicks in (assuming you are actually moving)

If it kicks in (ie driving on muddy or snowy roads) while driving, you CANNOT feather the throttle to bring the vehicle around to make the turn.

It is as if someone just disconnected your pedal. IMHO, the computer should allow the driver to apply *some* feathering of the pedal, regardless of wheel spin.

Been in some hairy situations before. Sometimes if you are certain to crash (haven't crashed the 4Runner, but had a deer run into the side once), it is important to get the vehicle sideways to spread the impact.

That limits damage to the vehicle and you.

A perfect example is a ditch on the side of the road. The wheels don't care if they go into a ditch (ie sideways at low speeds), but the front end would crumple much easier if going into a ditch/bank head on....

I used to race cars on a dirt track, and getting it sideways many times avoids most damage with a few cosmetics only, whereas a forward impact easily bends and crunches lots

Now...

The controls are great for S-type of swerves (over steering on slick surface) and will practically claw into the pavement- great!

But, it is downright dangerous by preventing the ability to avoid a forward impact, like hitting an icy corner.

How's that for a rant? Without the info above, my next question probably wouldn't have made any sense...

Just saying that removing all throttle control from a driver poses unexpected risks.

Oh yeah, the point.... If you discover which mode is performing the "kill engine" part, is there some way to override just that part while retaining the "equalize the wheel spin" part?

Now THAT could be a winner!

-DiskDoctr

 

[Thai]

Re: Can cause problems...

I used to race cars on a dirt track, and getting it sideways many times avoids most damage with a few cosmetics only, whereas a forward impact easily bends and crunches lots
-DiskDoctr

The problem with this is that YOU have racing experience...99% of other people do not. Unless Toyota can find someway to individualize each vehicle's dynamic systems, you got to assume that Toyota is taking the safe way to cover for the general mass skills or lack of.

 

[SP Jon M3]

What purpose, then, does the '08 VSC off switch serve when Traction Control is still able to de-throttle the engine?

The VSC Off switch in the '08s turns off VSC if you push the button. If you hold it again for three seconds it'll turn off VSC and TRAC.

From the Manual page 184:

When getting the vehicle out of mud or newly fallen snow, etc., turn off the vehicle stability control system. This system that controls engine performance interferes with the process of freeing rear wheels (two-wheel drive models) or 4 wheels (four-wheel drive models).

To turn off: First, push the "VSC OFF" switch to turn off the traction control system and check that the "AUTO LSD" and slip indicator lights come on. Then, push and hold the "VSC OFF" switch for 3 seconds or more with the vehicle stopped.

The "VSC OFF" and slip indicator lights will come on.


To turn on: Briefly push the "VSC OFF" switch once again.

 

[DiskDoctr]

Re: Re: Can cause problems...

The problem with this is that YOU have racing experience...99% of other people do not. Unless Toyota can find someway to individualize each vehicle's dynamic systems, you got to assume that Toyota is taking the safe way to cover for the general mass skills or lack of.

Thai,

The racing was an example. I live in an area that often gets a bunch of snow at once and not much plowing in our area. The same issues with slippery corners, snow on the roads, etc have applied for many years in all different vehicles.

The VSC does create some difficulties.

With all the experiences and knowledge folks on here have, I figured most would understand the need to feather the gas sometimes instead of just slamming the pedal to the floor when hitting slippery areas.

I was considering the audience to whom I was writing. But that's why we have 4Runners instead of cars, eh

SP Jon M3- I have the 04 and can turn off the VSC (and do when playing offroad ), but the trouble comes when you unexpectedly hit the slippery stuff... Thanks for the reply, though.

-DiskDoctr

 

[leftyrb]

Monday night we had snow. I usually try to active theVSC/traction control at least once per year. I have a wide road that I turn onto before I reach my house. When slippery, I can crank the steering to make the turn, hold the wheel in that position, they apply the accelerator, as to to try to make the vehicle spin out. On Monday night, I attempted this, the buzzer and light came on, and then brakes were applied and throttle reduced and vehicle straighted out. I straighted steering wheel, pressed the accelerator and off I went.

 

[DiskDoctr]

I usually try to active theVSC/traction control at least once per year.

Who are you trying to kid? :awais:

Pretending you are just doing some kind of "maintenance thing" by trying out the VSC/TSC?

We ALL know you are just PLAYIN with your Runner! :biggrin2:

We've all been there, we have the same disease

Try disabling the VSC/TSC and unlocking the diff if you want to spin out. heh-heh.

-DiskDoctr

 

[snhrph]

Re: Re: VSC and Traction Control both de-throttle engine..

The VSC Off switch in the '08s turns off VSC if you push the button. If you hold it again for three seconds it'll turn off VSC and TRAC.

From the Manual page 184:

When getting the vehicle out of mud or newly fallen snow, etc., turn off the vehicle stability control system. This system that controls engine performance interferes with the process of freeing rear wheels (two-wheel drive models) or 4 wheels (four-wheel drive models).

To turn off: First, push the "VSC OFF" switch to turn off the traction control system and check that the "AUTO LSD" and slip indicator lights come on. Then, push and hold the "VSC OFF" switch for 3 seconds or more with the vehicle stopped.

The "VSC OFF" and slip indicator lights will come on.


To turn on: Briefly push the "VSC OFF" switch once again.

Is that a 2WD or 4WD