Shut off TCS for a day!

Here are some speculations that might be worth considering.

The TCF and DSC systems monitor conditions 200 times per second. Minute, repeated, undetectable application of the brakes may be applied with TCF on. That's one theory for why some drivers see meaningful mpg gains with TCF OFF. It would also account for why some owners report premature brake wear.

Something else now comes to mind. In repeated testing of the Lane Keeping / Lane Departure, as often as not my vehicle does not detect lines on the left under optimal conditions, whether double yellow, broken yellow, white on expressways, as I very gradually sidle up to and over them when the systems should engage. Other functions that use the forward facing camera work fine, so I discount camera miscalibration. Is some minute TCS / DSC braking putting LS / LD in standby based on some unique factor in my vehicle when these systems do not activate when they should?

Some folks do not encounter this issue of LK / LD not activating. Or as one poster I recall reported, his fails to detect white shoulder lines on the right without complaints about lines on the left. Mine's the opposite--fine with those shoulder lines.

How to account for the differences? Is it conceivable that tiny adjustments with tiny amounts of braking monitored 200 times per second vary from vehicle to vehicle depending on tiny factors like road smoothness, condition of the tires and brakes, or even performance adjustment codes in the PCM since engine torque adjustments are factored into TCF/DSC on vs. off? Could how much weight is in the vehicle, or even how it is distributed, make a difference?

Could Mazda engineers answer these questions? Maybe, maybe not. It's highly doubtful these varying conditions have been tested. Is there one Mazda mind with a comprehensive understanding of all the code and the hardware involved in all aspects of these systems that interact with each other? No. Nothing would ever get done. There would be an overall architecture but various engineers work on specific pieces, software and hardware. All the meetings and note comparisons in the world won't get you to a perfect integration on paper. Integration problems might get uncovered in testing and they get fixed as best they can without a major redesign. I seriously doubt testing of new tires vs. worn ones, for example, is performed in product testing and even if it was perfecting a system for optimal operation under both conditions might not be possible.

Of course there's no practical advice to be gleaned from this noodling, so carry on.
 
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I just want to confirm that if you restart your car the TCS is re-enabled like the manual sez even though the TCS light sez its "Off" Can someone do me a favor and start car, turn off TCS, turn car car, then restart car, and after restart tell me if the TCS light still sez "off".

Cheers
 
I just want to confirm that if you restart your car the TCS is re-enabled like the manual sez even though the TCS light sez its "Off" Can someone do me a favor and start car, turn off TCS, turn car car, then restart car, and after restart tell me if the TCS light still sez "off".

Cheers
In my case, a 2017 Mazda 6, yes, you have to push the TCS button each time you start the car to deactivate it. The default on startup is that the TCS is active (light off).
 
That's interesting. I did a word search on "TCS" in the PDF format of the 2020 North America manual (79 instances) to see what TCF OFF might affect. There's no mention of cruise. Did you try to engage radar cruise, conventional cruise, both? I've not yet tried it myself.
I always use the radar cruise. That is the default setting when you hit the mode button on the steering wheel. It would not engage, and a warning message appeared on the dash cluster, although I didn't write it down. I'll try it again in a day or two, and this time I'll make note of the wording in the warning message. I tried to engage the non radar cruise setting, and I couldn't do that either. When I activated the TCS again, it went into cruise with no problem. As soon as I pushed the TCS button to deactivate it, the cruise kicked out.
 
Here are some speculations that might be worth considering.

The TCF and DSC systems monitor conditions 200 times per second. Minute, repeated, undetectable application of the brakes may be applied with TCF on. That's one theory for why some drivers see meaningful mpg gains with TCF OFF. It would also account for why some owners report premature brake wear.

Something else now comes to mind. In repeated testing of the Lane Keeping / Lane Departure, as often as not my vehicle does not detect lines on the left under optimal conditions, whether double yellow, broken yellow, white on expressways, as I very gradually sidle up to and over them when the systems should engage. Other functions that use the forward facing camera work fine, so I discount camera miscalibration. Is some minute TCS / DSC braking putting LS / LD in standby based on some unique factor in my vehicle when these systems do not activate when they should?

Some folks do not encounter this issue of LK / LD not activating. Or as one poster I recall reported, his fails to detect white shoulder lines on the right without complaints about lines on the left. Mine's the opposite--fine with those shoulder lines.

How to account for the differences? Is it conceivable that tiny adjustments with tiny amounts of braking monitored 200 times per second vary from vehicle to vehicle depending on tiny factors like road smoothness, condition of the tires and brakes, or even performance adjustment codes in the PCM since engine torque adjustments are factored into TCF/DSC on vs. off? Could how much weight is in the vehicle, or even how it is distributed, make a difference?

Could Mazda engineers answer these questions? Maybe, maybe not. It's highly doubtful these varying conditions have been tested. Is there one Mazda mind with a comprehensive understanding of all the code and the hardware involved in all aspects of these systems that interact with each other? No. Nothing would ever get done. There would be an overall architecture but various engineers work on specific pieces, software and hardware. All the meetings and note comparisons in the world won't get you to a perfect integration on paper. Integration problems might get uncovered in testing and they get fixed as best they can without a major redesign. I seriously doubt testing of new tires vs. worn ones, for example, is performed in product testing and even if it was perfecting a system for optimal operation under both conditions might not be possible.

Of course there's no practical advice to be gleaned from this noodling, so carry on.
the 200 times per second thing is the AWD system
 
same here. All cruise control functions work.
Buzzman12 what year is your CX5? is it the non turbo model?
It's a 2017 6 GT with tech option. All the gadgets that were available that year. Same stuff as what is in the CX-5. They should work the same. Like someone said, maybe the Canadian car is somehow different. I'll go back out in a day or two and play with it some more and post any updates.
 
If in a FWD the TSC was creating brake wear why do the back brakes wear first as they are not used by TSC?
 
I can confirm the lane assist and lane tracking turns off the moment you turn off TCS... which is lame because next to the TCS button is the lane assist Off button :)
But it is what it is... for me its not a big miss because the lane assist is very dumb on the US CX5 anyway.
Cruise control keeps working all the time for me.

Regarding the brake wear I think TCS is for all wheels and the reference to the wear was for the rear brakes as those are the ones which usually go first based on the forum reports. But its all speculation at this point.
 
the 200 times per second thing is the AWD system
There's no reason to believe that TCS / ABS / stability control in FWD systems are not monitoring conditions at an equal speed. I'm not finding a Mazda marketing piece extolling the virtues of FWD like the one that talks about AWD. They wanted to sell you an AWD system. We know that for sure now at least in the US.
 
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If in a FWD the TSC was creating brake wear why do the back brakes wear first as they are not used by TSC?
Just a theory:

TCS / ABS / stability control work in concert while at least ABS and stability control are using all four brakes even in a FWD version. Turning off TCS may reduce the frequency of stability control application and / or alter it's behavior. Under this theory, stability control under TCS just happens to be harder on the rear brakes.

In fact, it is not entirely clear to me whether turning off TCS deactivates stability control entirely.
 
Just a theory:

TCS / ABS / stability control work in concert while at least ABS and stability control are using all four brakes even in a FWD version. Turning off TCS may reduce the frequency of stability control application and / or alter it's behavior. Under this theory, stability control under TCS just happens to be harder on the rear brakes.

In fact, it is not entirely clear to me whether turning off TCS deactivates stability control entirely.

Within a month of buying the CX5, turned off LK/LD and TCS and noticed the couple mpg increase in gas mileage and was able to "feel the road". At one point was tracking and it gave a good 2 to 3 mpg boost.

When took it to mechanic for him to look for any warranty items, he noticed the system was off, and asked "what I was doing?"

I explained why turned it off.

He used to race stock/ modifieds down at the local speedway so trust his opinion.

He said "ok it's your car, but when you crash it...".

He recommend that I at least keep it on during rain, snow, curvy mountain driving and Offroad/gravel.

Basically everything except for dry pavement on straight highway roading.

As for gas mileage apparently when it's on its constantly making small minute corrections, braking & acceleration, sometimes against our driving habits, etc. basically a countering effect which increase gas usage.

Will have to ask him about stability control next time take Mazda in for any type service.

Although he may not know...

Maybe someone else can put in an inquiry to Mazda. Already asked them a few myself.
 
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Snip...
Within a month of buying the CX5, turned off LK/LD and TCS and noticed the couple mpg increase in gas mileage and was able to "feel the road". At one point was tracking and it gave a good 2 to 3 mpg boost.

I have to agree on your "feel the road" comment. It's hard to explain it exactly but it's true. With TCS off I can feel the road more than with it on.
 
⋯ Regarding the brake wear I think TCS is for all wheels and the reference to the wear was for the rear brakes as those are the ones which usually go first based on the forum reports. But its all speculation at this point.
IMO the main reason why rear brakes went a lot earlier on the CX-5 is because they’re under-designed. Just look at disk pad specs between front and rear, the thickness is thinner and the area is much smaller on rear. I was surprised to see the pad thickness on rear is only 8.5 mm instead of industry standard 10 mm! No wonder rear brakes are gone early.

Front brake (disc)
Pad dimensions (area x thickness) (mm2 x mm {in2 x in}) 6,000 x 10 {9.300 x 0.39}

Rear brake (disc)
Pad dimensions (area x thickness) (mm2 x mm {in2 x in}) 2,800 x 8.5 {4.340 x 0.33}
 
IMO the main reason why rear brakes went a lot earlier on the CX-5 is because they’re under-designed. Just look at disk pad specs between front and rear, the thickness is thinner and the area is much smaller on rear. I was surprised to see the pad thickness on rear is only 8.5 mm instead of industry standard 10 mm! No wonder rear brakes are gone early.
I know we're getting slightly off topic, but besides the smaller size of the rear brakes, the main reason they wear out faster is the that newer cars have a rear brake bias designed into them. What this means is that the rear brakes grab slightly earlier and harder than the fronts. This is intentionaly designed in the system to reduce, or almost eliminate, nose diving when first stepping on the pedal. You can google it and see exactly how this is done. I found one site for Hyundai that gave a very clear and easy to understand explanation on how it works.
 
The reason that rear pads are wearing more than they used to is 'electronic brakeforce distribution' (EBD), which is part of the ABS.
https://en.wikipedia.org/wiki/Electronic_brakeforce_distribution

This is what also prevents vehicles from nose-diving during hard braking. Front brake pads have always been thicker than the rears because historically they always wore down faster. EBD is used in most vehicles now, but brake systems haven't been redesigned to use thicker rear pads
 
He recommend that I at least keep it on during rain, snow, curvy mountain driving and Offroad/gravel.

Basically everything except for dry pavement on straight highway roading.

As for gas mileage apparently when it's on its constantly making small minute corrections, braking & acceleration, sometimes against our driving habits, etc. basically a countering effect which increase gas usage.
I don't think you have to limit it to straight highways. So long as the road is paved and in reasonably good shape, clear of water, snow or ice, and you don't drive aggressively, you'd be fine. If you're going to tear a*s through turns and curves, that's another matter.

The idea that TCS applies the brakes in less than aggressive driving with some frequently in undetectable increments while stability control alters torque with TCS off (or disables stability control?) is just a theory to explain the significant gas mileage improvements some folks are reporting. I'll stick with that theory as most plausible until there is a better idea.

Results may vary. Vehicles of the same year / trim / drive train should be regarded as fraternal twins, not identical ones. I have a hard time believing I'll improve on my TCS ON results, 33-34 mpg I've gotten on long stretches of freeway doing 60-75 mph or 31 mpg on a day trip on part expressway, mostly 2-lane blacktops with periodic stop signs and lights with 800 lbs. of people in the vehicle. It'll drop to 25 if there are a lot of 8 mile round trips to and through the village on that tank.

I would also monitor yourself to see how real the mpg savings happen to be. Are you driving more conservatively as you figure out how the vehicle feels with TCF OFF?
 
The reason that rear pads are wearing more than they used to is 'electronic brakeforce distribution' (EBD), which is part of the ABS.
https://en.wikipedia.org/wiki/Electronic_brakeforce_distribution

This is what also prevents vehicles from nose-diving during hard braking. Front brake pads have always been thicker than the rears because historically they always wore down faster. EBD is used in most vehicles now, but brake systems haven't been redesigned to use thicker rear pads
Your wiki link states the following:

"Typically, the front end carries more weight and EBD distributes less braking pressure to the rear brakes so the rear brakes do not lock up and cause a skid. In some systems, EBD distributes more braking pressure at the rear brakes during initial brake application before the effects of weight transfer become apparent.

Wouldn't it stand to reason that the Mazda design intent is the typical one given the smaller brake pads on the rear? Of course it is possible that the electronic implementation defeated the purpose, but something tells me other factors are involved.

If you go to the following video at the 2:40 mark you'll see a panic stop from 30 mph with noticeable nose dive, one indication of front bias.

 
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IMO the main reason why rear brakes went a lot earlier on the CX-5 is because they’re under-designed. Just look at disk pad specs between front and rear, the thickness is thinner and the area is much smaller on rear. I was surprised to see the pad thickness on rear is only 8.5 mm instead of industry standard 10 mm! No wonder rear brakes are gone early.

Front brake (disc)
Pad dimensions (area x thickness) (mm2 x mm {in2 x in}) 6,000 x 10 {9.300 x 0.39}

Rear brake (disc)
Pad dimensions (area x thickness) (mm2 x mm {in2 x in}) 2,800 x 8.5 {4.340 x 0.33}
Are those specs for a particular gen, year, trim? AWD vs FWD or turbo vs. non? I know, that's a lot of questions. Anyway, for the version(s) you're quoting I'd be curious to know the OEM rotor spec differences between front and rear.
 
As far as I know all CX5 gen2 have the same specs except the Turbo which has larger front discs and most likely pads. I have somewhere the discs dimensions if you are interested let me know and I can take a look.
 
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