The myth of the DSC OFF switch
 

In many posts I came across that to de-activate dynamic stability control and traction control you have to press and hold the DSC switch for about 7 seconds. Then the DSC OFF light illuminates along with the car with the curvy lines as well.

All that this procedure does is tells the system of a possible problem with the switch (since the switch was designed to be a momentary switch) thus turing both the DSC and TCS systems off.

In reality, as the owner manual explains, by pressing the DSC OFF switch (without holding it) will turn off DSC/TCS and DSC OFF light will illuminate.
The only time the car with the curvy lines illuminates (flashing) is 1) when the system is being activated (DSC/TCS operating when needed), 2) flashing when you turn the key to on position or 3) solid on when there is a malfunction.

The function that stays on regardless of DSC/TCS is brake LSD.

Please, any feedback would be appresiated.

PS> NOTE that when you press the DSC OFF switch, the DSC OFF indicator illuminates.. Then, you can drive to the limits and the car with the curvy lines indicator will never illuminate indicating the the DSC/TCS system is OFF.

Owner's manual states:

This indicator light stays on for a few
seconds when the ignition switch is turned
to the ON position.
It also comes on when the DSC OFF
switch is pressed and TCS/DSC is
switched off.
If the light stays on when the TCS/DSC is
not switched off, take your vehicle to an
Authorized Mazda Dealer. The dynamic
stability control may have a malfunction.

It also says:

If the DSC OFF switch is pressed
and held for a second or more, the
TCS/DSC system may become
inoperative due to the system
detecting switch trouble. If the TCS/
DSC system becomes inoperative,
the TCS/DSC and the DSC OFF
indicator lights illuminate
simultaneously. In this case, turn off
the engine and restart it to restore the
TCS/DSC.

Maybe it’s just me but what is the point of this thread? DSC / TC cannot be permanently disabled

You just restated what we already know.
Push DSC button once = > DSC off till you cycle the ignition on/off again.
Hold DSC button 7+ seconds => DSC AND TC is off until the next ignition on/off cycle.

If your claiming that the TC is in fact on and the curvy lines light is on because it thinks there is a problem with the switch I invite you to do a 5,000 RPM clutch drop with the TC ‘off’ and with the DSC/TC on.

No. That is not what I stated.

Push DSC button once -> DSC and TC off until you push the button again or until the next ignition cycle.
Hold DSC button 7+ seconds -> It does the same thing as pushing DSC button once but in this case the DSC and TC is turned off not by a button push request, but by a fault code interpreting a faulty switch. Therefore, the TC light illuminates solid to indicate a malfunction.

You aren't telling us anything we don't know. Because of the 7-second hold, the 'computer' thinks there is a problem with the switch and shuts off both DSC and TCS.
Both are off until the car is re-started.

Yes. We know that.

Expo....
 

You are probably right, but one of your sentences is not - "Push DSC button once = > DSC off till you cycle the ignition on/off again."

If you tap once the light comes on, tap again = back on, no need to cycle ignition.


S

Here's why you hold the button... Page 5-24 in the '04 Manual, Right column...

When you just press the button once, the brake LSD function (brakes still activate to steady the car somewhat) STILL HAPPENS. So technically, the TCS/DSC is off. Technically.

When you press and hold the button until you see the TCS/DSC light illuminate (car with squiggly lines) it shuts off the brake LSD so there's no intrusion at all in sprited driving.

Hopefully, that clears up your confusion.

--kC

How can you conclude that by pressing and holding the button it shuts off the brake LSD system?

1) Real world driving in a competition environment with the button in any of the three positions. a) ON, b) Off with just DSC Light Illuminated and c) off with both TCS/DSC Lights illuminated. Drastic differences between the three.

2) With just the button pushed once, there is still intrusion from the system as it applies brakes (at a lesser amount) according to the manual. Notice it doesn't say the "system" is disabled, just 2 functions of the system. (TCS/DSC). I have experienced the brake LSD function with only the DSC OFF indicator illuminated.

From the manual:Notice the distinct lack of the use of the word "system" in that phrase.

3) The manual even goes on to state that it deactivates the entire "system" when you push and hold the button for more than 7 seconds.

Use of the term "System" includes the 3rd function of the TCS/DSC ... brake LSD.

Hope that helps.

--kC

Thanks... I'll look closer at the manual... I'm not sure if my 05 owners manual might be a little different...

what it says from your own post

If the DSC OFF switch is pressed
and held for a second or more, the
TCS/DSC system may become
inoperative due to the system
detecting switch trouble.

if you tap the button the DSC is turned off sort of. its more like asleep. it can still intervene if it feels like it. and traction control is still active. it can be turned back on by tapping the button a second time.

if you hold it for 7-8 seconds and the dash indicator becomes illuminated then it is telling you the whole system, Traction control and Dynamic Stability Control, is inoperative and will stay that way until the next ignition cycle.

If the dash indicator becomes illuminated when you have not held the button its telling you the system has become inoperative. one of the reasons this could happen is a short in that button giving a constant signal

How can you tell that the traction control is still active. The manual states that DSC and TCS will turn off when you push the button.

Also, when you push the button to turn the system off, the system should not intervene if it feels like it because it is off.
Like I stated before... no matter which way you turn the system off (pushing the button or holding the button), both DSC and TCS will turn off. It is just a matter of how the system interprets the request. (button press vs. switch fault)

You go ahead and keep believing that. I explained it very thoroughly above. the brake-lsd is a function of traction control, one element of it.

In order to totally disable all aspects of traction control, you have to push, and hold, the DSC button. Just turning off DSC so where only one light is illuminated, does not totally disable the SYSTEM.

I would believe that its worded the way it is in the manual is because you have people that would say "The manual said I can do this!" They want to discourage the total disabling of the TCS system. This is why it's till partially active with the button press.. it keeps the sue happy at bay. If you totally disable the whole system, it's "do so at your own risk, we told you not to, and we told you what would happen".

Go into your DSC/TCS enabled vehicle. Press the button once. Turn the wheel a little bit, rev to around 6k rpm, drop the clutch.... what happens? Yeah.

Now, do it again, but this time, hold the button down until the Car/squiggly lines appears then do the above.

You will notice two different outcomes. Better yet... go park on some beach sand and then try to get out.

--kC

You probably mean EBD (Electronic Brake-force Distribution which adjusts the braking force to each wheel independently). This is not linked to traction control.. It's part of ABS. LSD is limitid slip differential which have nothing to do with the breaking system nor traction control) It's just the mechanics and sensors of the differential.

Well... in any event... I think this thread should have never been started and it will just keep going in circles without getting anywhere.

Please note that I'm not trying to argue here.... I'm just trying to clarify certain things that are not stated in the owners manual and that people "think" is going on but not really showing me any prove other than (personal experience).

I'll just keep trying all different scenarious of DSC/TCS and see what best suit my needs....

its going in circles because you wont believe the people with the personal experience.

I think you nailed it - this guy wants to believe what he does; he doesn't seem to be teachable.

(shrug).

I have first-hand evidence as to the difference between 'dsc off' and '7-second hold'. I've also seen video evidence, too.

maybe there's some confusion about what each system does.

abs: controls deceleration (duh!)
traction control: controls forward acceleration only (think of abs, but in reverse)
dynamic stability control: controls lateral acceleration (yaw)
limited slip differential: distributes and regulates the amount of torque applied to each wheel, though i don't know who this is controlled by the system. anyone?

Well... this is what the manual says...

I rest my case until proven otherwise...

You rest your case? Excellent.

Then...by Preponderance of Evidence, I find in favour of Everybody but YOU in this thread. :)

f what the manual says. why cant you just go try what these ppl are telling you is fact? LIke someone stated, they are not going to tell you how to disable something that can come back on mazda or any car company. If you do not belive these ppl, go try it so you can prove them wrong. but i can tell you this , you will not be able to. im not being a prick to you so please do not take it taht i am. im just saying is, if you have not tried for your self to see if it is accurate. then you have no argument to bring to the table to prove others are wrong.

well, from my experience (contrary to forum opinion) I did donuts in the snow with the DSC button in the 1 touch off position... no TCS and no DSC even came on -shrug-

With DSC OFF lighted my car will do all kinds of burnouts and donuts. Until a point. At that point (whatever the computer decides) the car starts behaving again. :)

I REALLY need to find that video I mentioned...

"...in the snow" sum's it up.
Now thats a good way to test the DSC... (sigh..)

I dont have DSC or RunDMC. I go drift now :bootyshak

Let me clear up some misconceptions about the systems you guys are discussing. There is no difference between "brake-assisted LSD" and "traction control".....why? Because traction control is brake assisted LSD. Dynamic Stability Control (DSC) IS TRACTION CONTROL. However, traction control is not DSC. It's like explaining the square and the rectangle. A square is a rectangle......but a rectangle is not a square. DSC encapsulates any computer aide to correct loss of traction/control. The loss of traction is based on inputs from the steering position sensors, wheel speed sensors and yaw sensors (body roll). The system corrects for loss of traction/control with outputs to the braking system and the engine controls.

I have an RX8 and always 'quick depress' the DSC button on dry pavement driving. I am able to lose traction anytime I want which means the DSC is not operating as a complete system. I have not taken the car to the limits of losing contact with the road, so I am not sure if the system will interfere at the point of roll-over detection.

Hey thanks for clearing that up. Makes sence.

Dont want to know on the second part of your post about the roll-over part lol. But someone did roll there car I did not think to ask them if the system tryed to pervent that.

I thought the brief button press disabled TC/DSC until ABS steps in. At that point, DSC activates to assist you with that maneuver and then goes back to sleep when the ABS system backs off (presumably when you have regained control).

:wallbash:

Evidently you wish to ignore the part that mentions (as I quoted above) that the MANUAL states "but the brake LSD function remains." You can interpret that any way you want, but it's in the manual. Albeit, the manual does not go on to describe what brake-LSD means... but it's there, and I, along with many others, have experienced it.

It's not a term/sentence I made up, it's a direct quote from the '04 manual on page 5-23. It means with just the one press, there's still something, whatever you want to call it, functional that will still be active, a braking system that will limit slippage, doofus. ([Alf]LSD.... Ha! I kill myself![/Alf]).

Then, near the same page referenced, there is mention that the whole kit and kaboodle is disabled, the whole DSC/TCS system.

One can make the logical reference that the brake LSD, whatever it is, is part of the DSC/TCS system, since it is referenced as such. By holding the button down, you are disabling the whole SYSTEM, again, as WRITTEN in the manual.

People like you are the reasons why they have "Lather, Rinse, Repeat" on shampoo bottles, because someone would read that and be caught in a viscous cycle.. how many times do you have to do it? The instructions say to repeat!! And "Do not apply metal suface to body when on" labels on Clothes Irons. You have to be told verbatim what you can and cannot do. And if it's not in the manual, well its gotta be wrong and you just can't use it that way!

Ever use a screw driver to pry something open? oh n03Z! That's NOT it's intended purpose!!

--kC
(Ripped the tag off his mattress) :ylsuper:

ABS is a very simple system......it modulates hydraulic pressure to prevent the brakes from locking up......that's all. ABS is always operating and usually cannot be 'turned off' by the operator. A vehicle can have DSC and not have ABS......but the ABS makes the DSC more robust by enhancing brake performance in low traction conditions.

I think the arguement is NOT that pressing and holding the button isn't disabling the DSC......it's that pushing the button once and holding the button for however many seconds results in the same effect on the DSC.

Does anyone have experience to disprove that statement? Basically, have you merely pushed the button once and driven to the point of computer intervention and then pressed and held the button, driven in the same fashion and did not experience the computer intervention?

I personally only press the button once and I have yet to have the computer intervene. I have fish-tailed in one direction, shifted to 2nd and fishtailed in the opposite direction into a spinning oversteer and still the DSC did not assist. I consider that to mean the DSC was off after just pressing the button once without holding it.

Not the roll-over point, but close. I've done back-to-back laps w/ the DSC OFF and the 7-second version of OFF. At the 7-Second version the car COMPLETELY loses control...the regular DSC OFF mode allows for some-loss of control, but at the edge (where ever that particular point is) the car loses power, and sorta comes back into line.

It's the difference between spinning off the track doing ONE complete spin (DSC OFF) vs 20 complete spins (7-Second-OFF).

Well that is a good case for something different happening with the system with the different button pressing procedures. I myself have not noticed a difference.....but then again I have not pressed and held the DCS button more than a couple of times in the past year. The reason being that I personally never noticed the difference. Doesn't mean there wasn't one though as you've clearly experienced a difference.

I REAAAAAAAAAAAAALLLY Need to find that video.. :)

On the street, I've never noticed a difference, because I drive at no more than about 7/10ths. On the track, I went from being able to take a corner okay - but really pushing it, to spinning on that same corner (using same entry speed, line, and such).

Do you tend to only push the DSC switch once then at the track to retain some control? Or do you feel it becomes a nanny too conservatively for track use?

So what happens if you hold the button for 5.312 seconds? :cwm27:

The tip of your finger starts to turn white :)

Oh, the horror!

There's this sport called Autocross that is a large lot or airstip set up with pylons. (Seach video.google for "autox video" any incar video will do as out of car doesn't give that much an idea) Each run through the course lasts about 60 seconds. In that time, there are no straights. It is a sport of constant transitions and controlling vehicle dynamics on the edge. Too little, and you're slow, too much, and you're looking the way you came. You're pretty much driving 9/10 - 10/10 for a constant 60 seconds.

With the one press DSC OFF, by the 3rd corner, I will feel the car trying to reel my driving in as I switch from left to right to left under power. Usually, this is when I am just about to exceed the slip angle of the tires... something I *need* to do, minimally in certain situations, to get a fast time. Especially with the car loaded in a sharp left turn, on the gas, with the inside left rear wheel unloaded. This is amplified on wet event days.

With the full 7 seconds, I will not have that. If I want to exceed the slip angle of my tires, it'll let me. It will not reel me in. I can put my car at any angle I want with as much throttle as I want. There's no intrusion. Granted, the intrusion is not as severe as with the DSC on, but it's still there, I and other can and have noticed it. It's mostly in the autox environment going 10/10ths on the limits of adhesion/traction/turning/gassing when you'll get the "brake LSD" (as what the manual calls it) activation.

On the road, you're most likely not going to feel it doing 7/10ths. Even on the track, you probably won't feel it as the inputs aren't as severe as auto-x. You have plenty of time to setup for the next corner, and many times, you're braking before you even get there (not so with auto-x).

So take it FWIW. It exists, the manual say so. They call it "brake LSD". The whole system can be deactivead by pressing, and holding, the DSC button for 7+ seconds until the Car with squiggly lines indicator comes on.

--kC

Nope. Pressing the button once disables the DSC. Says so right in the manual. Pressing the button and holding it not only disables the DSC, but also the brake LSD (Traction control) whatever you want to think it is. (The manual sucks in this regard with the explanation and inconsistanct terminology). You can get the car sideways with both ways. Except that the one press will only get you sideways to a certain amount... after that amount is exceeded, it says 'whoo! you've gone far enough!' and engages, per the manual, the brake LSD (I argue, is Traction control).

See my post above explaining auto-x. Short answer: yep.

You're not trying hard enough! ;) Get thee to an auto-x. It will all become apparant.

--kC

That is a good explaination about the difference in the different settings achieved by the DSC button pressing procedures. Again, I have not been commenting to the fact that anyone is right or wrong about the setting.....I was merely pointing out how the systems work as I set-up service strategies for these components for Ford.

Just out of curiousity, does this methodology hold true between all model years?

(meaning, will just pushing the DSC button do one thing on an '04, and then do something completely different on an '05)

Thought I'd ask because I think I saw this question come up, but I don't remember seeing a response...

Please don't mention the manual again to prove your point......I tend not to believe those manuals completely as they are written by the marketing dept and the system is designed by the engineering activity. Unless you've worked for an auto company, you probably don't know how little they communicate with each other outside of heated meetings and pissing contests. Your first-hand experience is much more credible to me than what the marketing dept 'thinks' the car can do. Case in point: advertised 250hp for the launch of the RX8.......HA! marketing wet dream.....I think experience on the dynos has taught us the truth.



You're probably right about not trying hard enough to lose control....but I have babies at home that need their daddy :)

What section on the manual is this... I have an 05 manual and I can't find it....

I'm not the one putting faith in the manuals. Thats the OP. :) (Hence my common references to "or whatever you want to call it" in previous posts when referencing what's still active on ehte one-press)

However, if the manual says something is going to happen, or a function of the system is still going to be active (brake-LSD) when you press a button to disable the larger function of it, it damn better well be active. Then, in the next para, when they reference not only particular components, but an entire system becoming disabled, (and that it could be written MUCH better than it is), I see, and know, the differences between the two paragraphs.... why?

I write training for the Navy. Trust me... I know the difference between manualspeak and techspeak. I have to walk that line and find out what the engineers MEANT and what the Tech Writers *thought* it meant. ;)

--kC

In the 04 manual, it's page 5-23, 3rd bullit in the right Note area.

If you have different page numbers (and you probably do...)

It's : Driving Your Mazda > Starting & Driving > Dynamic Stability Control > Note:.

The box is just after the DSC OFF switch section (Last part of DSC section, just before the TPMS section.)

--kC

I guess no business has a monopoly on ambiguity :)

This is what my manual shows. It does not state about the 7+ seconds hold of the switch nor about shutting off brake LSD.

As a question was raised in this forum....: Is it true for all model years?
_________________________________________________

>Leaving the TCS/DSC on will
provide the best stability. When the
TCS/DSC is off, the TCS/DSC does
not activate but the brake LSD
function remains.
l
>If the DSC OFF switch is pressed
and held for a second or more, the
TCS/DSC system may become
inoperative due to the system
detecting switch trouble. If the TCS/
DSC system becomes inoperative,
the TCS/DSC and the DSC OFF
indicator lights illuminate
simultaneously. In this case, turn off
the engine and restart it to restore the
TCS/DSC.

Personal experience: At a Mazda RX8 ride and drive (a Mazda event for employees to feature the car before it comes out) they had a circle set up with plastis tarps and soapy water. We were told to go into the circle at 30 mph and dont let off the gas. DCS worked perfectly to correct understeer, amazing! We then were told to do the same with DCS "off" (switch pushed once) and do it again. Knocked over alot of cones, brake LSD still will function (traction control), more understeer. Tried it again with the button held until traction control light came on. Completely understeered and had no control. Many cones jammed underneath car. Did the same thing with the Mazdaspeed 6 last year. Good clean fun.

puch do your self a favor and just keep the DSC/TSC on, in fact put black tape over it, so you can forget it even exist.

Forget the manual for a sec. It was written by lawyers from second-hand info passed through Japanese to Engrish on its way to the USA and elsewhere.

A few quick notes about the various systems:

The LSD (limited slip differential) has no electronic component. It does what it does in a vacuum. Its job is to simply distribute torque to the rear wheels. It does nothing else and it does so with impunity.

The ABS (anti-lock braking system) is a 4-wheel anti-lock scheme. It detects a sudden non-rotating state of any wheel under braking and automatically modulates that wheel to get it rolling again.

The TCS (traction control system) is a throttle modulating scheme that pulls power from the rear wheels whenever it detects a differential between the rotating speed of the fronts and the backs.

The DSC (dynamic stability control) is an over-arching control scheme that utilizes the TCS and ABS sensors to modulate the throttle and the brakes to dampen yaw.

The ABS cannot be defeated without a fault. Unplugging its harness will kill it and the DSC and throw a CEL.

Pressing the DSC button for a second will lower the threshold of the TCS system and remove the DSC.
Pressing the TCS/DSC button for 3 or 4 seconds faults the DSC system and turns both completely off and throws a fault light.
Neither of those actions affect the ABS or the LSD.

Regardless of what the manual states, this is what happens. I'm sure you are quite earnest in your beliefs Puch96, but they are based on the literature and this forum is chock full of refutations of the literature - some from driving experience and others from people living with their scopemeters and diagonal cutters.

I have attached a scan of the a relevant page of the 1005 Owners Manual.I interpret this to mean that when the DSC OFF switch is pressed and the DSC LIGHT is illuminated then the TCS/DSC is switched off except that the ABS system will still act as a Limited Slip Differential.If you hold the DSC OFF switch until the TSC/DSC Indicator light illuminates then the WHOLE TSC/DSC system becomes inoperative.Of course the mechanical LSD will still function.