zoomalot

I had a winter tire set from The Tire Rack installed by my dealer. A master technician wondered about wheels without TPS and called Mazda - the Tech Line, I believe they said. Mine was the first 8 they had installed winter tires on.

The dealer was told by Mazda that it is not recommended to run wheels without TPS because the sensors affect not only the TPMS but also ABS and DSC. The implication being, of course, that those other systems would also malfunction. This per Tech Assistance Reference 322819.

This just doesn't sound correct to me. I have never heard or read of any such connection. Did I miss something? Has anyone else heard such a thing from their dealer, or any other source?

I requested that they install the winter tire set anyway. All I've seen is the flashing TPMS light, just as expected.

Gord96BRG

It's either pure BS, or Mazda Canada has a lot of explaining to do! The RX-8 in Canada is not equipped with the TPMS, but does have ABS and DSC. My stability control and ABS systems work just fine, despite my car not having TPMS. I've been running winter wheels/tires for 4 weeks now, and the DSC and ABS still work just fine, as they did with the OEM wheels/tires (again, which don't have tire pressure transmitters in them either).

If you want to confuse your dealer, ask him how the Canadian RX-8s are different since they have functioning ABS and DSC with no tire pressure monitoring system.

Regards,
Gordon

silvercloud

Zoomalot,

Have you tried to active the DSC and ABS with the new wheels?
Do they kick in?
I'm wondering because I have wheels/tires on the way from the Tire Rack.

MazdaManiac

iTrader: (3)

From what I can glean from the shop manual wiring diagrams and diagnostics, the TPMS is independant and won't affect ANYTHING if it is disabled.
It is only connected to the ECU via the CAN buss to report errors. That is it.
ABS is independant as well. DSC is integrated.

zoomalot

I haven't had the opportunity to activate either ABS or DSC with the winter wheels and tires on. There are no warning lights signaling except for the TPMS.

Tire Rack said all the information they have indicates that the information from the dealer is not correct. They had not heard of such a thing from other customers.

Mazda may be promoting sensor sales.

zoomalot

Well, the BS alarm went off for me.

It did cross my mind about the Canadian cars. The whole idea just didn't make sense. It doesn't exactly inspire confidence to think that a master tech would buy it. The service writer said this is a technician who attended the RX-8 school.

zoomalot

Thanks for looking in the shop manual. Are you familiar with Tech Assistance References, what weight they carry, and how they may relate to TSB?

SnyderMazz

Maniac is right, they are indepentdent. The TPS system has no control over the ABS. Give it up to Mazda for trying to sell something that the car doesnt even have lol My Master Tech (who has attended RX8 school) said (in regards to the TPS and non-stock tires), " Doesnt matter as long as the TPS system is still connected. Its apart of the valve stem and wheel itself, not the tire. It has no bearing on the ABS or any other systems. Its only job is track air pressure. The only thing you might get from not running the TPS system is that [annoying] light."

Also if you ABS goes out, you still have regular brakes regardless. You dont understand how many customers I get that freak out because the ABS light is on lol I know, Im beating a dead horse, but I wanted to add that comment in

zoomalot

SnyderMazz,

Can you find out what Tech Assistance Reference 322819 actually says? I think it should be corrected or retracted. If it's something that is distributed or posted by Mazda, it could give incorrect information to to other dealers and customers. With it, Mazda could attempt to say that if a problem arises with ABS, it is caused by running wheels without TPS and the warranty would be void in such a case.

zoomalot

I had the first really snowy communute with the 8 today. I can tell you that the ABS and TCS are functional and working fine. (This without tire pressure sensors in winter wheels.) As expected, what Mazda told me through my dealer is false.

silvercloud

Thanks for the info Zoom

syntrix

Or could it be the dealer misinterpreted Mazda Tech line?

Wouldn't the Tech Assistance Reference number be like an order number? IE, they issued that to the service tech to reference their tech line database, and owner information with?

Have you emailed or called MNAO directly about this information?

zoomalot

The Service Manager said the Tech Assistance Reference was by phone. It could be misinterpretation. He says they don't have it in writing. It must be on record somehow at MNAO, though. Today the Service Manager said he would contact the Tech Line to (hopefully) get a correction. This erroneous information could be going out to other dealers. I have not called Mazda myself. I wanted my dealer to follow through on what they told me.

syntrix

Glad the dealer is following up! Keep up posted!

Blue Demon

So, is this right?

Press the DSC button and it turns off the traction control but leaves the stability control on. Only the DSC indicator sights up.

Press and hold the DSC buton for several seconds and it turns off both traction control and stability control. Both DSC and stability control indicators light up. This condition will remain as long as the key is in the on position, will reset to the default of both systems on upon turning the key off then on again.

Blue Demon....

rx8daniel

I believe that both remain on when just the "DSC OFF" light is lit, the condition you get when you just press and release the button. They remain what most might judge a 'civilian' amount of control. Holding it down until the skidding car symbol lights turns it entirely off(or if not 100% off about 98%), and yes, you can't get it back on without shutting the power off. I believe it might have been eccles who wrote extensively about experimenting with it on one of his first autocrossing outings in his 8. Do a search for autox or autocross and / or traction control and you should find it!

Reeko

Guys,

I think that I understand TC, I think it applies brakes to one or both of the rear drive tires if they loose traction.

But I wanted a better discription of DSC.
Does it actually apply brakes individually to any of the four tires? Even if you are not accelerating?

The reason I wanted to know is that I am trying to understand what it can and cannot correct for. Is there a good description of its capabailities and also what it can't do?

Thanks
Rick

WHealy

TC - Passive traction system that leverages ABS sensors. When it senses the a wheel are moving at a velocity faster than the vehicle, it applies the brake to that wheel until it matches vehicle speed.

DCS - Measures direction the vehicle is traveling compared to the direction of the front wheels. If the two directions are different, the vehicle is either in or entering a skid. This system then applies brakes singularly to the appropriate wheel or wheels to correct the skid.

That's off the top of my head, but I think it's pretty acurate. If not, I'm sure others will chime in.

DisneyDestroyer

I don't believe it applies brakes in either condition, only drops RPMs (cuts gas) until things get back in line.

91vert

No.....I believe it applies the brakes.

I started sliding my car sideways on purpose on the wet roads a couple of weeks ago just to see what would happen, and the back brakes started chattering and groaning like the ABS was kicking in. The DSC literally straightened the car out itself in like a split second. It was the freakiest feeling thing. I did not even touch the brake pedal. The car just took over and did what it needed to do.....which included applying the rear brakes to straighten me out.

sferrett

The DSC most definatley applies the brakes... The TCS I think cuts power (if you try to do a burnout for example) - if you try to take off around a corner (like a dounut) then you get both...

The first time the DSC kicked in for me was going down a hill around a 15mph corner and got into some understeer, it scared the bejeezus out of me because I thought the front wheel was falling off when the ABS/brakes kicked on (noise more than anything). Now I'm used to it and can feel when it's gonna kick in, so I either avoid it or I'm ready for it.

WHealy

Edmunds definitions :

Traction Control

Traction control deals specifically with lateral (front-to-back) loss of friction during acceleration. In other words, when your car accelerates from a dead stop, or speeds up while passing another vehicle, traction control works to ensure maximum contact between the road surface and your tires, even under less-than-ideal road conditions. For example, a wet or icy road surface will significantly reduce the friction (traction) between your tires and the pavement. And since your tires are the only part of your car that actually touches the ground, any resulting loss of friction can have serious consequences.

Traction control is part of a series of three braking technology developments that began appearing in vehicles in the mid-eighties. (Note: Many German vehicle manufacturers call traction control by its original German name: ASR traction control. ASR stands for "Acceleration Slip Regulation." It's the same technology we're talking about here, but with a fancier name that most Americans have never heard of.) In chronological order, these developments are: anti-lock brakes, aka ABS (1978), traction control (1985), and stability control (1995). All three technologies come from the laboratories of Robert Bosch Company in Germany, and all address the issue of improving contact (traction) between your car's tires and the road.

Traction control works at the opposite end of the scale from ABS -- dealing with acceleration rather than deceleration. Still, since many of the same principles apply to both systems, it might be best to visualize it as sort of ABS in reverse. ABS works by sensing slippage at the wheels during braking, and continually adjusting braking pressure to ensure maximum contact between the tires and the road. You can actually hear the system working (a grinding sound) and feel it (the pedal pulsing).

As we mentioned above, ABS and traction control operate similarly. In fact, the ABS control unit is the basic "building block" for traction control and stability control. By adding modules and sensors, the system can be expanded to include these newer technologies.

In the case of traction control, the basic ABS system -- as well as other components in the vehicle -- requires some modification. To begin with, the old-style accelerator cable is typically replaced by an electronic drive-by-wire connection (although some older systems still use a mechanical accelerator cable), meaning the mechanical hook-up between the accelerator pedal and the throttle ceases to exist. Instead, a sensor converts the position of the accelerator pedal into an electrical signal, which the control unit (similar to the one used in ABS) uses to generate a control voltage. The standard ABS hydraulic modulator is also expanded to include a traction control component.

All these parts work together to activate the traction control system.

Let's say you're at a stoplight on wet pavement. The light turns green and you press too firmly on the accelerator pedal. There is slick asphalt under your tires and the wheels begin to spin. The traction control system instantaneously kicks in, sensing that the wheels have begun to slip. Within a fraction of a second, this data is fed back to the control unit, which adjusts throttle input and applies braking force to slow the wheels (some older systems also retarded engine spark). The wheels are thus prevented from spinning and the car maintains maximum traction.

It's really that simple. Again, think of it as ABS in reverse.

Full article


DSC

This brings us to our present topic: stability control. The third "building block" in modern braking systems, stability control incorporates everything ABS and traction control do plus a yaw-sensing feature that works to increase traction during potential side-skidding situations. In other words, whereas both ABS and traction control work on the longitudinal (front-to-back) axis of the vehicle, stability control operates on the lateral (side-to-side) axis. Bosch's Electronic Stability Program (ESP), the first such system on the market, began appearing in 1995 Mercedes-Benz S-Class sedans. It has since become a popular feature on many upscale vehicles.

According to Bosch's Kosmider, "The platform for ABS, traction control and stability control is essentially the same. We simply add sensors to get the desired effect."

In addition to discrete electrical components, ceramic sensors and solenoid valves, stability control systems typically utilize wheel-speed sensors, steering-angle sensors and a hydraulic modulator. The key component is, however, something called a rotational speed sensor (also known as a yaw-rate sensor). Yaw can be described as "the movement of an object turning on its vertical axis."

The yaw-rate sensor determines how far off-axis a car is "tilting" in a turn. This information is then fed into a microcomputer that correlates the data with wheel speed, steering angle and accelerator position, and, if the system senses too much yaw, the appropriate braking force is applied.

As you can imagine, stability control systems are particularly effective in inclement driving conditions, where the roadway may be covered with rain, ice or snow and the normal friction between the tires and the road is reduced.

There are a couple of things you may want to know about stability control. First, the system will do most of the "thinking" for you. Depending on the particular driving situation, the system may activate an individual wheel brake or any combination of the four, as well as control the throttle, until the vehicle is once again stable.

Second, the system is fully independent of the driver's actions. Even if the car is free-rolling (no acceleration or braking input from the driver), the stability control system will kick in and perform its duty. All you need to do is steer.

Remember, though, that stability control, like any technology, is not fool-proof. All vehicles must ultimately obey the laws of physics. Members of our road test staff report spinning sedans with activated stability control systems on dry pavement. Be sure to make your driving decisions based on the appropriate criteria — visibility, road conditions, speed, the condition of the tires and brakes — and not to rely on any technology to correct for unsafe driving.

Full article


Originally, TC and DSC systems only came on automatic transmissions. Now I've never seen this documented anywhere, but I assume that they bridged the gap to manuals by using traction control with DCS reducing speed by braking as opposed to throttle control. But that's just a theory.

SQ88

Does anyone know if TC and DSC systems can be added to the RX8 without one from the factory? If so, where can it be done?

Thank you for any input.

WHealy

SQ88,

I never say never, but I can honestly say that i have never heard of anyone doing what you are suggesting. Anything is possible with time and money, but I would think it would be more cost effective to take the hit trading your car and buying one with the GT package. Of course that includes additinoal options that may be of issue. I know for me, I would have prefered the heard room as opposed to the sun roof.

Good luck.

huhsler

Has anyone noticed that residual brake whistling (or squeal) goes away when the DSC is completely turned off, using the 5 second method?

Is it just me? ...or, am I just crazy? ;-)