JYOO

Whats the speed limit before VSC doesnt come on? Whats the fastest anyone has been when the light came on? Is it like the cheesy unit on the Acura TL where it only comes on when you are going under 15 MPH?? Thanks.

Johnny Mo

If it doesn't come on above 15mph it is not VSC it is traction control...it only senses wheel slippage from standstill or near standstill.

VSC in the Lexus stands for Vehicle Skid Control and has pitch and yaw rate sensors to determine what the car's "attitude" is and compensates by braking some or all of the wheels to "correct" the skid. During the AMCI ride and drive this is done at 55-60 MPH (VSC on and VSC off to show the difference). People who are good drivers and know how to correct a skid already will actually be worse off with this because it will confuse the car's computer, although the speed at which VSC reacts is getting faster and faster as the technology improves.

ShowGSLuVv

I've had it come on when was doingabout 50 MPH before, the road was wet and i stepped on the gas and the light started blinking

ShOwGS

QBranchCars

From LexusSafety.com;

VSC
Vehicle Skid Control

Vehicle Skid Control (VSC) senses the onset of loss of lateral traction and helps the driver stay on track. Input from four wheel-speed sensors, a yaw-rate (directional) sensor, a deceleration sensor, and a steering-wheel-angle sensor is communicated to the VSC system's computer. The system has the ability to reduce power and to control the brake actuator. Working with both ABS and TRAC, the VSC system helps the driver to compensate for loss of lateral traction, which can cause skids and loss of vehicle control.

VSC System Computer

Assimilates the data from all safety sensors and matches it against preprogrammed algorithms to determine if the vehicle is maintaining excess speed for the degree of cornering attempted, and whether any of the wheels are beginning to slip (lose traction). If this condition is detected, the computer determines which wheel (or wheels) should apply brakes and whether the engine should also reduce power to maintain its proper cornering attitude and direction.

TRAC
Traction Control System

All-speed Traction Control (TRAC) works by automatically modulating engine power by decreasing airflow to the engine and applying the rear brakes selectively to help control wheelspin in rain, ice and snow, or in other reduced-traction conditions. If one drive wheel starts to spin, its brake is applied, transferring torque through the differential to the opposite wheel, to help provide better grip on the road surface to help you gain control. The system helps the driver maintain control of the automobile and optimize traction, even on slippery surfaces.


Johnny, I still don't see how VSC can have negative affect irregardless of driver experience. I would think that the VSC computer dynamically checks all inputs and manipulates the engine/brakes as necessary. Are you saying the VSC would actually hamper the experienced driver's throttle input for understeer, and steering input for oversteer skids?? Was this demonstrated at the AMCI event? Pls clarify.

enginyr

I read the 1998 yaw sensors were defective. Anyone else read this?

Dvlad

VSC(vehicle stablity control) is a nice "safety net" to have. But as the wise man once said... Nothing can stop the law of physics.

Johnny Mo

Calvin,

they only demonstrated the on/off of vsc, they didn't really show how an experienced driver could "confuse" the VSC computer. I have only heard this from other experienced driver's, bu thave never tried/experienced it myself...sorry if I caused any confusion.

power3dfx

to anyone who is wondering exactly how much vsc can actually interfere when the car is being pushed to beyond its limits. i have a stock 2k gs4 if you are wondering,although it should make no difference. first off, i noticed that vsc wont kick in for a sec. or two from a standstill. you could probably spin the wheels for almost two seconds before vsc kicks in and puts a stop to it.
next, i have lost complete control one time, taking a right turn at about 20 with wet road. the car was fishtailing all over the place, and not only the vsc light stayed on, but also a beep sound continued until the car straightened up.

if you push the car just to the point that it just barely lets loose of the road, for example taking a long turn at about 60, vsc intervenes, typically without a beep.

if you are really pushing the limits(especially if it is sudden), vsc will once again take over and the beep sound may be present.
although vsc can usually help in any situation where the driver makes an error, it will not help you if you really are doing something stupid i.e. take a right turn at 70, kiss your butt goodbye. it can't defy the laws of physics.

power3dfx

finally, i dont encourage at all that you go out and test vsc or any other skid control systems on any car. these safety devices are meant to assist the driver should a problem arise, in an emergency. hopefully, you will never need vsc to kick in, but be thankful that its there making even the most stupid driver look like a skilled racer.
sorry if my explanations are cramed togethere, im very tired

wwest

Qbranchcars:

You seem to have more detail than I have been able to gleam from the Rx and GS shop manuals, do you have access to something like theory of operation?

itsallgood

You guys are to technical for me.

vsc on, no tire spin

vsc off, tire smokin green lights

just my .02