Why doesn't traction/stability control actually turn off?

[Ganthrithor]

Originally Posted by ottopilot

Probably try to prevent a rollover.

That's bad form right there: you're not supposed to hit the mirrors :P

[Ninjin]

Originally Posted by Ganthrithor

Hey duders,

I was driving my car in a spirited manner today and noticed that-- despite having held down the stability control off button and gotten the two amber lights on the cluster-- the traction control system engaged a couple of times while trying to slide around some slightly bumpy, vertical hairpins. This is not the first time the system has intervened (while "off") on vertical corners or where there are significant undulations in the road surface.

What's this about? Do I need to do the bloody pedal dance to prevent this? Why does the VSC system tolerate all kinds of retarded shenanigans on flat surfaces / dirt, but freak out the moment there's a bump in a corner?

This is kind of frustrating...

I've noticed this behavior on uneven surfaces as well. My theory is that the stability control (specifically the use of individual corner braking to prevent the car from spinning) and traction control (specifically the metering of power + brakes to prevent wheelspin) are indeed fully OFF. However there are at least three features I know of that won't be turned off by depressing the trac off button until the two lights come on.

1. What I think you're seeing is the "auto-LSD" feature. Because the torsen LSD will become an open diff if one wheel is completely in the air; the car is programmed to apply the brake to a rear wheel if it senses that wheel is not touching the ground, or about to break traction. This is pretty easy to achieve with certain suspension setups or uneven surfaces. This feature activating is probably what is causing the "slip light" on the dash to flash at you in corners. This feature is disabled with the pedal dance diagnostics mode.

2. ABS - As far as I know you'd have to pull a fuse to disable ABS. ABS activation shouldn't trigger the "slip light".

3. EBD - Electronic brakeforce distribution. As with ABS, I don't think this feature triggers the slip light at all, and it can be disabled with the pedal dance diagnostics mode, but doing so can have negative consequences (since the ABS system is programmed to rely on the presence of EBD).

[a2cpc]

Originally Posted by Ganthrithor

That's bad form right there: you're not supposed to hit the mirrors :P

It is only a 3 point deduction though!

[Ganthrithor]

Originally Posted by Ninjin

I've noticed this behavior on uneven surfaces as well. My theory is that the stability control (specifically the use of individual corner braking to prevent the car from spinning) and traction control (specifically the metering of power + brakes to prevent wheelspin) are indeed fully OFF. However there are at least three features I know of that won't be turned off by depressing the trac off button until the two lights come on.

1. What I think you're seeing is the "auto-LSD" feature. Because the torsen LSD will become an open diff if one wheel is completely in the air; the car is programmed to apply the brake to a rear wheel if it senses that wheel is not touching the ground, or about to break traction. This is pretty easy to achieve with certain suspension setups or uneven surfaces. This feature activating is probably what is causing the "slip light" on the dash to flash at you in corners. This feature is disabled with the pedal dance diagnostics mode.

2. ABS - As far as I know you'd have to pull a fuse to disable ABS. ABS activation shouldn't trigger the "slip light".

3. EBD - Electronic brakeforce distribution. As with ABS, I don't think this feature triggers the slip light at all, and it can be disabled with the pedal dance diagnostics mode, but doing so can have negative consequences (since the ABS system is programmed to rely on the presence of EBD).

The last few times I've gotten the slip light it's felt like the throttle was being electronically modulated. I assume if the electronic LSD function took over that you'd still get power delivery to the outside wheel (since the braking would cause the diff to lock up again?), so you wouldn't get the sensation of throttle input being ignored?

[kevman_101]

I kept my finger on the Traction control button, got both lights, and lost it in a 2nd gear turn with no indication of any aids getting in the way. I know in sport mode, it saved me once again in a 2nd gear turn so I know the difference.

[WolfpackS2k]

Originally Posted by hushypushy

100% certain. Go drive the car hard enough, your skepticism will (unfortunately) be erased.



This is EXACTLY my experience.

My car is completely stock. I've autocrossed it and gotten it way sideways...no problems at all. However, when driving swiftly through very bumpy turns, I've seen the flashing VSC light in the cluster more than once.

Kind of a bummer

Guess I'll have to find a nice big parking lot somewhere next time it rains really hard and figure it out for myself, hehehehe

[quickfrs]

I was having luck holding the TC switch for 10 seconds+ and was able to slide the car like I wanted. I had an incident where it tried to swap ends on me and after that it doesn't matter what I do even though I get both yellow lights on the TC kicks in just like I never touched the button. How does this happen? I even took it out in the rain and "turned off" the TC and deliberately tried to slide the car and the
TC wouldn't let me. Anyone know what's going on here?

[Ganthrithor]

Originally Posted by quickfrs

I was having luck holding the TC switch for 10 seconds+ and was able to slide the car like I wanted. I had an incident where it tried to swap ends on me and after that it doesn't matter what I do even though I get both yellow lights on the TC kicks in just like I never touched the button. How does this happen? I even took it out in the rain and "turned off" the TC and deliberately tried to slide the car and the
TC wouldn't let me. Anyone know what's going on here?

That's weird as hell. If this happened to my car and wasn't correctable I would sell it immediately. Just saying.

I say take it dealer immediately.

[WolfpackS2k]

I know this could be stating the obvious, but you guys aren't trying to deactivate the TC while moving are you? The traction control can only be fully deactivated (or so the manual says) when you are stationary.

[lazyluka]

TC and VSC are NEVER fully deactivated by pressing the TC button down for more than 3 seconds.
TC is deactivated by simply pressing the TC button for a short period, but this will keep VSC ON and TC will re-engage past a certain speed limit (don't remember off by heart now, but its something low like 40km/h).

The above is true regardless of if the vehicle is moving or stationary.

Sometimes the light will flash and it won't intervene (it will but you won't notice it, possibly due to loss of traction by lift/bump on one wheel or something similar due to torsen LSD) or other times it will emergency brake for you.

The only way to turn TC off fully as mentioned before is Pedal Dance (which keeps ABS functionality) or to pull the ABS fuse which also disables ABS functionality. I do not suggest doing either of these on the public roads. The car does have an EDR and if it is shown you have used either method you risk you claim being declined by your insurance* as this was beyond the "normal" scope of operation that the car was designed for. In another words, the manufacturer did not specify this in the user manual therefore it can be considered as a modification to the vehicle, even though it is temporary.

If you want to know how I know, it's because I used the 3 sec off system, and the car saved my a** when I lost control and started going backwards due to a 180 spin. It managed to slow me down (by performing an emergency brake) to 17km/h before I rolled off a cliff. I have a few emails from Toyota describing the system operation.

The pedal dance/abs fuse was not discussed with Toyota as I didn't see the need to.

*I am not an expert on this subject, but this is what I have concluded with dealing with my insurance company here in New Zealand. I had a nice friendly chat to them regarding the TC system affecting insurance and that was the conclusion I came to after the talk.

[nmctacticz]

VSC is good to go, but as soon as I press traction/stability control off the fucker turns back on just as Im driving normally. And if I try drifting around a corner it turns back on instantly as Im trying to drift. I even tried holding down the button as Im drifting and it still turns back on lol

[Stang70Fastback]

Here's a question. VSC sport in videos I've seen seems to allow moderate drifts around turns. I know it obviously allows for a larger slip angle, but that all seems kind of pointless to me because it doesn't seem to increase the TCS margins at all, so say I'm on a wet curve, and I wanna have a little fun. Unless I do some sort of Scandinavian Flick, I can not get the back to step out, because trying to do so with the throttle just leads to the TCS stepping in to stop wheelspin. Even if I DO flick the car into the turn, I can't do anything with the throttle to prolong the turn because TCS will step in. It's really irritating because IMHO, it seems to render sport mode completely useless to me. As a result i never use it. I'm just in normal mode most of the time, or full off. I'd love to leave it in sport mode so that I could have that added margin of safety, but the car doesn't seem to let me do anything at ALL in that mode.

[HeadBanger]

Originally Posted by nmctacticz

VSC is good to go, but as soon as I press traction/stability control off the fucker turns back on just as Im driving normally. And if I try drifting around a corner it turns back on instantly as Im trying to drift. I even tried holding down the button as Im drifting and it still turns back on lol

Stop your car. Hold the button until the two amber lights come on. Now your traction is "off". When you press it once it sort of acts like a launch control. It will allow a little bit of slip, then catch the tires.

[Ganthrithor]

Yeah, sport mode doesn't really let you drift or anything, it just lets you drive the car hard. You can add throttle in a corner to the point where you feel a little suggestion of slip, like the rear end is just smearing a little bit around the corner, but the computers will stop you as soon as you get any visible yaw rate going.

Sport is perfect for street driving-- just enough leeway to let you enjoy yourself. If you want to go sideways in the rain / snow / whatever you just have to turn it off (as everyone's said, hold down the off button until you get the two amber lights).
@Stang70Fastback I liked your parking lot video :3