Traction control issue?

[mit_peid]

In all honesty, I just treat the traction control on my FR-S 6MT like a toggle switch. Most of the time if I want it off I would just hold down the left button ~5 sec so all the traction/VSC lights come on. But seems like there are various degrees of disabling using combinations of the TRAC button and the right VSC button, but seems like it should/would affect the Auto more than the MT.

I have noticed something recently that got me curious, my left traction control button is intermittent when I simply press it momentarily while driving. Sometimes the TRAC OFF light would come on but other times nothing happens. Not sure when it is allowed and when it isn't allowed to come on. The long 5 sec press still works every time to turn all nannies off. Any idea?

[DJ_Joee]

Originally Posted by mit_peid

In all honesty, I just treat the traction control on my FR-S 6MT like a toggle switch. Most of the time if I want it off I would just hold down the left button ~5 sec so all the traction/VSC lights come on. But seems like there are various degrees of disabling using combinations of the TRAC button and the right VSC button, but seems like it should/would affect the Auto more than the MT.

I have noticed something recently that got me curious, my left traction control button is intermittent when I simply press it momentarily while driving. Sometimes the TRAC OFF light would come on but other times nothing happens. Not sure when it is allowed and when it isn't allowed to come on. The long 5 sec press still works every time to turn all nannies off. Any idea?

Its a toyota system as i used to have it on my TC and now same with the BRZ, pressing the left "Trac off" button for half a second will disable the traction cantrol action momenterly and only works under 30km/h i beleive, this allows you to escape from a pile of snow or ice if ever stuck (it will let both wheels turn freely without controling their engine power nor braking on them, Lsd is still active though)and will the go back on by itself. Now a half second press of the right vsc sport button tunes down the computer assistance in the vehicle and lets you have a bit of fun but will attemt to save your live if control is lost (more experienced drivers will see a contrary effect :p and would prefer to turn off all the gismos completly). Last but not least the "lets have some fun mode" and i really do not suggest anyone to use it unless you had enough experience with this toy because she can be extreemly tail happy and that could be dangerous or fatal, press and hold "trac off" button to turn off all electronic assistance except for ABS of course!

[mit_peid]

Thanks I'll take it out today and try the 1/2 sec press below and above 30km/h (don't make me do the conversion to mph right now ) and then see if it goes away automatically.

[DJ_Joee]

Originally Posted by mit_peid

Thanks I'll take it out today and try the 1/2 sec press below and above 30km/h (don't make me do the conversion to mph right now ) and then see if it goes away automatically.

Haha you americans always have to be different :p dont quote me on the speed im not sure but it acts that way at a certain speed you can figure the rest out

[ayau]

The half second trac off button will also let you get wheel spin from a dead stop. Useful if you're just doing launches. I've forgotten to turn off trac when launching and it just accelerates like a snail.

[AdrianG]

Here's how the traction works on the Canadian version (I don't know if other markets are different):

- VSC Sport mode can be enabled with the right button at any speed. It will stop reducing power so much but will still apply rear brake if you slide more than a little bit.
- A short press of the left button will disable traction control until speeds exceed ~40km/h (or until the rear wheels reach 40km/h). This can be combined with VSC.
- A long press will disable traction/VSC and remove power restriction and the car will no longer apply rear brakes when you slide. The system will however turn itself back on if it detects a zero-grip scenario on the rear wheels (for example, one comes off the ground). On top of this, you still have the other computer aids (ABS, EBD). This can only be done when the speed is under 50km/h (though the manual says you have to be stationary).

To turn EVERYTHING off you need to do the pedal dance. This will permanently disable traction control as well as ABS & EBD. You're on your own until the car is restarted, and the traction buttons do nothing. The pedal dance must be done with the car fully warmed up and stationary within a minute of starting.

- Start the car (mine's MT so I move it to neutral at this point)
- disengage the e-brake if it is on
- pull the e-brake 3 times, locking it on on the third pull
- tap the brake 3 times, holding it on the third
- release and pull the e-brake 3 more times while holding the brake pedal, locking on the third pull again
- release and tap the brake pedal 2-3 more times

If it worked, the traction control lights will come on and the traction buttons won't turn it off again. The only way to re-activate the assists are to restart the car.

[CSG Mike]

Originally Posted by AdrianG

- A long press will disable traction/VSC and remove power restriction and the car will no longer apply rear brakes when you slide. The system will however turn itself back on if it detects a zero-grip scenario on the rear wheels (for example, one comes off the ground). On top of this, you still have the other computer aids (ABS, EBD). This can only be done when the speed is under 50km/h (though the manual says you have to be stationary).

This *can* be done on the US version of the car while moving, if you're not activating the system via driving. E.g. if you're driving on the highway, you can still do the long press.

If a rear wheel lifts or the system detects single wheel spin, the "electronic diff" is still active, and will engage. This will be indicated by the slip light flashing in the tach, and the VSC/TC lights turning off. They will turn back on and the slip light disappear when the car stops detecting single wheel spin.

This CAN happen while hard driving, and will force the car to understeer, which is why we recommend anyone tracking do the pedal dance. At this time, I can replicate this issue at will.

[Porsche]

Originally Posted by AdrianG

To turn EVERYTHING off you need to do the pedal dance. This will permanently disable traction control as well as ABS & EBD.

The ABS is disabled?

Maybe, but I'd be surprised if this were true.

Perhaps someone could test this on the road/track. It would be easier on the tires to test this in the wet to avoid "squaring off" your tires if in fact the ABS is disabled.

[CSG Mike]

Originally Posted by Porsche

The ABS is disabled?

Maybe, but I'd be surprised if this were true.

Perhaps someone could test this on the road/track. It would be easier on the tires to test this in the wet to avoid "squaring off" your tires if in fact the ABS is disabled.

ABS is not disabled. EBD is.

[Porsche]

Originally Posted by CSG Mike

ABS is not disabled. EBD is.

That's my understanding, yes.

Mike, can you share your experience with the EBD being disabled. It is my understanding that these cars no longer employ a brake proportioning valve to manage the front -> rear brake balance under varying conditions. The EBD now manages that; but, if it's disabled, then wouldn't both front and rear wheels get identical brake force? That's not good...

I'm only speculating here, but I'm concerned about doing the pedal dance for the street and then finding myself zooming into a downhill corner out in the country and having my rears lock up and try to pass the fronts into the corner.

I don't like that kind of excitement.

Can you share your experience, please, and help me understand this better?

Thanks.

[CSG Mike]

Originally Posted by Porsche

That's my understanding, yes.

Mike, can you share your experience with the EBD being disabled. It is my understanding that these cars no longer employ a brake proportioning valve to manage the front -> rear brake balance under varying conditions. The EBD now manages that; but, if it's disabled, then wouldn't both front and rear wheels get identical brake force? That's not good...

I'm only speculating here, but I'm concerned about doing the pedal dance for the street and then finding myself zooming into a downhill corner out in the country and having my rears lock up and try to pass the fronts into the corner.

I don't like that kind of excitement.

Can you share your experience, please, and help me understand this better?

Thanks.

The system, from my experience (no actual measurements) has a front bias. Unless you purposely put a much more aggressive compound in the rear, you won't have any rear locking up issues.

In fact, you won't have any rear locking up issues since ABS is still active

What it does do, is let you properly trail brake.

[OrbitalEllipses]

Any front engine car is going to have significantly more front brake than rear brake. Only mid and rear engine vehicles will deviate from that.

[Porsche]

Originally Posted by CSG Mike

The system, from my experience (no actual measurements) has a front bias. Unless you purposely put a much more aggressive compound in the rear, you won't have any rear locking up issues.

In fact, you won't have any rear locking up issues since ABS is still active

What it does do, is let you properly trail brake.

Thanks, Mike.

[Porsche]

Originally Posted by OrbitalEllipses

Any front engine car is going to have significantly more front brake than rear brake. Only mid and rear engine vehicles will deviate from that.

That is correct in a NORMAL setup, a setup employing either a properly functioning front/rear brake proportioning valve, or an EBD computerized system. (Electronic Brakeforce Distribution).

Doing the pedal dance creates an ABNORMAL setup; the EBD is now disabled. The EBD was there for a good reason. It was to create the stable balance you describe as true of "any front engine car."

But, we've just turned it OFF. Your description may no longer be applicable.

That changes things. There could be unintended consequences if the rear brakes are now getting the same hydraulic pressure as the front brakes. Due to weight transfer under heavy braking, the fronts can tolerate a great deal more braking pressure before locking up than can the lightly loaded rears.

(I know you know this, Orbital, I'm elaborating a bit for the benefit of some of our readers who may be less familiar with these issues.)

On another note, it's interesting to see that a number of autocross competitors who have tried the pedal dance have found it to be counterproductive, creating worse problems than the one they were trying to solve. A number of those competitors avoid the pedal dance.

I suspect their experience may be due to the very sharp corners they encounter where they hike their inside hind leg (wheel) well up into the air, thus locking it up under braking, which then gets the ABS system riled up. It doesn't like that. Mike, on the other hand, is driving through much larger radius corners on road courses where I suspect he has both rear wheels rolling on the ground.

I'm just speculating about all this stuff.