bealljk

iTrader: (13)

Mic ... teaching moment, sir ...

does the yaw sensor/system have any influence on the traction control system? Or is that purely the SRS system?

Is the tolerance/threshold a moving target? Meaning is 7% at speeds under 30mph and 3% from 30mph to 70mph and 1% at 70mph+??


Different trims (base vs. performance vs. touring vs. track) have different methods (i.e. traction control vs. vdc) ... does traction control use only braking means/methods while VDC uses both braking and retarded timing means/methods? or vice versa?

Sebastian777

A lot to take in here. The car was up on blocks for about a month. Could being more exposed to the elements, due to no wheels covering the end of the axle, have caused sensors or something else to rust and throw the calibration off?

Is there anything that can be easily checked just by pulling the wheels off?

Also, I have new TPMS sensors that have not been programmed to the car yet, could that be causing any issues?

bealljk

iTrader: (13)

Take it to a shop to have the sensors checked. it's not a DIY type of thing...

an alternate would be to purchase new wheel speed sensors, install, and see if your problem comes back.

I dont think the TPMS have anything to do with it...

Sebastian777

Are speed sensors a DIY install? Does it take a specialized shop to check speed sensors or can any mechanic/tire shop do it?

bealljk

iTrader: (13)

I believe they are relatively easy ... disconnect a from ~18" away from the wheel, 2 bolts holding the sensor in place, remove, reinstall - I dont think there is any recalibration or reconfiguring ... but I'm not 100% sure...google it and let us know what you find.

MicVelo

Vehicle dynamic control (VDC) incorporates traction control (TCS) as a sub-system as a controlling mechanism to stop/slow the "slipping" wheel(s).

So yes, VDC does influence the TCS.

If you look at a VDC equipped car, you'll note that it is the only one (to my knowledge, corrections welcome!) that contains the yaw sensor. Said sensor monitors the vehicle angle (versus TCS that "just" monitors wheel speeds in relation to one another and applies the brakes or cuts throttle to reign in the offending wheel/tire).

VDC monitors vehicle ANGLE about the vertical axis and compares to the steering wheel angle sensor(s) and wheel speed sensors. If any of the condition are not within spec, it triggers VDC and yes, does so in proportion to vehicular speed which the ECM always knows.

It's quite a complex system but at the same time works on pretty simple principles.

S'far as whether one system uses the other, YES. As mentioned, VDC is dependent upon TCS as one of the mitigating controls. And TCS uses both wheel braking AND engine power limiting.

To take it further into "complex" territory, TCS (hence VDC) both rely on anti-lock braking (ABS) and brake force distribution (EBD) in order to safely bring the vehicle back into relative "control".

IOW, alphabet soup.

Open to correction but that's how I understand it.

Breakdown my model type:

Base - No stability controls
Enthusiast - TCS only
Performance - VDC
Touring 6MT - VDC
Touring 5AT - TCS only
Track - VDC

terrasmak

iTrader: (8)

Steering angle sensor and header install, I’ve screwed up. Was off by. Full rotation of the wheel, the car was undrivable with VDC on. If the sensor is off, system is crummy.


Back to the OP. Walk to the car, look at tire sizes. Shops have screwed up, they have also done their own thing thinking its for the best.

dboyzalter

iTrader: (3)

My stock sized tires did the same thing when I had half worn fronts and brand new rears of a different brand.

Maybe you were slipping a little bit on those turns, sometimes those streets be slick.

dboyzalter

iTrader: (3)

The speed sensors are pretty easy to replace, they are held on by 1 bolt each, I think if they were the issue the abs system would be throwing a code and your brake system would be messed up... The occasional slip light while taking a turn makes me think its got more to do with the tire size...

If the tires are stock sized and all good I would try a reboot on the computer... Just disconnect the negative for a few hours...

bealljk

iTrader: (13)

I was ~8 degrees off and the TC lights flashed me at higher (80 - 90mph) speeds...

at the event this past weekend I ran my RPF1s w/the R888 on the rear and my RS with the proxes 4+ up front and at/around 120mph my TC light flashed and my ignition cut my speed (in a straight line with my steering angle corrected) ... the proxes are 2" greater in circumference (measured with a piece of string) ... I wish there was a way to add some tolerance...didnt have the ***** to turn TC/VDC off (didnt want to be 'that guy')

JMII

My experience (including tracking my car) is you have to be pushing pretty hard or driving on a slippery surface (wet road) to get the slip light. In "normal" driving it should almost never come on provided you have the right size tires with enough tread.

Sebastian777

Update: so I tried resetting the computer, still have issues. Is checking the speed sensors something any shop can do, or is it time to talk to a stealership?

bealljk

iTrader: (13)

I tend not to go to the dealership unless I absolutely absolutely absolutely have to...a experienced independent mechanic will be able to help you out.

Sebastian777

Haleylooya...
Hallelugha..
Halleluyah..

Hell Yeah! Problem solved. Always seems like it's the dumb simple things. Posted this question in a Facebook group and a guy asked me what my tire pressure was. Went out and checked it, it was over 40 psi in each tire, cold. Dropped it to 35 psi in each and problem is now gone.

Quick questions.
1. The tires were not slipping, at least in any way I could perceive. So what did the extra air in the tires do to activate traction control? Surely 5 lbs of pressure didn't change the diameter enough to matter.

2. I know 35 psi is the recommended tire pressure, but is that to be measured at cold or running temp?

dkmura

iTrader: (64)

Just had a similar question from a friend who thought VDC was activating, but it turned out the dash light in question was the low tire pressure warning. Checked his tire pressures and the rears were underinflated. BINGO! Low pressure light goes out and his system is working just fine.

The recommended tire pressure is to be measured when the tire is cold. Keep in mind this will change as the ambient air temp changes.

JMII

40 cold could be as much as 50-55 after driving hard once things heat up.