IS - 2nd Gen (2006-2013) Discussion about the 2006+ model IS models

VSC and TRC

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Old 07-27-06, 10:05 PM
  #1  
ahbwee
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Default VSC and TRC

Hi everyone,

i'm a newbie to is250RWD.

what's the diff between VSC and TRC?
please advise as to what exactly these 2 terms control.

also, How diff is VDIM in is350 compared to VSC?

and by doing the pedal dance, for my is250rwd, what does it switch off?VSC?or TRC?or both?

i've done a search but couldnt really find a satisfactory explanation.
please advise.thanks for patience.
Old 07-28-06, 01:04 AM
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flipside909
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Originally Posted by ahbwee
Hi everyone,

i'm a newbie to is250RWD.

what's the diff between VSC and TRC?
please advise as to what exactly these 2 terms control.

also, How diff is VDIM in is350 compared to VSC?

and by doing the pedal dance, for my is250rwd, what does it switch off?VSC?or TRC?or both?

i've done a search but couldnt really find a satisfactory explanation.
please advise.thanks for patience.
Vehicle Skid Control = with traction control, an electronic system that controls engine output and brake application on individual wheels to help control loss of traction in turns.

TRAC = electronic traction control system uses both throttle and brake intervention to help control rear wheelspin.

VDIM = is a system which integrates braking (ABS and BA = brake assist), steering (variable gear ratio steering = VGRS), Vehicle Stability Control (VSC) [and Traction Control (TRAC) systems to help minimize loss of traction in a turn.

Here are some good descriptions and demo clips of how VSC and TRAC is seamlessly controlled by VDIM:

http://www.lexus-europe.com/technolo....asp?model=All
http://www.lexus.com/models/is/demo_.../vdimDemo.html

Here's an older article from The Auto Channel:
http://www.theautochannel.com/news/2...14/125451.html

As for the pedal dance, it allows you to disable both TRAC and VSC simultaneously which in essence will allow you to spin your tires as needed. The pedal dance for the TRAC/VSC disable is not to be confused with calling it a "VDIM OFF" sequence. Since the pedal dance will work with most modern Toyota and Lexus vehicles i.e. Avalon, IS250/250AWD, GS300/GS300AWD, these vehicles listed do not have VDIM. The only vehicles that have VDIM in the lineup are the Toyota Highlander & Camry Hybrid versions, Lexus RX400h, GS450h, GS430 and IS350 only.

Last edited by flipside909; 07-28-06 at 01:09 AM.
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Old 07-28-06, 11:34 AM
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jsquared
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Originally Posted by flipside909
Vehicle Skid Control = with traction control, an electronic system that controls engine output and brake application on individual wheels to help control loss of traction in turns.

TRAC = electronic traction control system uses both throttle and brake intervention to help control rear wheelspin.

VDIM = is a system which integrates braking (ABS and BA = brake assist), steering (variable gear ratio steering = VGRS), Vehicle Stability Control (VSC) [and Traction Control (TRAC) systems to help minimize loss of traction in a turn.

Here are some good descriptions and demo clips of how VSC and TRAC is seamlessly controlled by VDIM:

http://www.lexus-europe.com/technolo....asp?model=All
http://www.lexus.com/models/is/demo_.../vdimDemo.html

Here's an older article from The Auto Channel:
http://www.theautochannel.com/news/2...14/125451.html

As for the pedal dance, it allows you to disable both TRAC and VSC simultaneously which in essence will allow you to spin your tires as needed. The pedal dance for the TRAC/VSC disable is not to be confused with calling it a "VDIM OFF" sequence. Since the pedal dance will work with most modern Toyota and Lexus vehicles i.e. Avalon, IS250/250AWD, GS300/GS300AWD, these vehicles listed do not have VDIM. The only vehicles that have VDIM in the lineup are the Toyota Highlander & Camry Hybrid versions, Lexus RX400h, GS450h, GS430 and IS350 only.
Wow, that was a great explanation. All the other threads I've read about it have been bits and pieces, so it was kinda hard to understand everything. This sums everything up in one nice post. Great job.
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Old 07-28-06, 11:37 AM
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Originally Posted by jsquared
Wow, that was a great explanation. All the other threads I've read about it have been bits and pieces, so it was kinda hard to understand everything. This sums everything up in one nice post. Great job.
My thoughts exactly - great post Ryan!!!

Javier
Old 07-30-06, 10:13 PM
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ahbwee
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these are the answers' i'm looking for.thanks a million

so, if i were to press the TRC off in my is250, floor the throttle with foot brake on, then release the foot brake, you reckon i can get wheel spin?
Old 07-31-06, 01:36 AM
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flipside909
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Originally Posted by ahbwee
these are the answers' i'm looking for.thanks a million

so, if i were to press the TRC off in my is250, floor the throttle with foot brake on, then release the foot brake, you reckon i can get wheel spin?
You should be able to. But you will get a one sided burnout since the 250 does not have an LSD to keep both wheels spinning at the same time.
Old 08-11-06, 02:40 PM
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This is how the Lexus Repair Manual describes our electronic nannies:
VDIM (Vehicle Dynamics Integrated Management)
DESCRIPTION
(a) This vehicle is equipped with VDIM. It is a concept of vehicle motion control that integrates brake control, drive force control and steering control.
(b) Conventional vehicles use a combination of independent functions such as ABS, TRAC, VSC and EPS. However VDIM integrates these systems to improve "drive, turn and stop", the motion performance of the vehicle in other words.
(c) In conventional vehicles, control starts at the limit of the vehicle. However VDIM exercises control before the limit is reached, creating a smooth vehicle response. This expands the limits of the vehicle, and increases driving pleasure.
(d) The VDIM manages all functions, such as the ABS with EBD, BA, the TRAC, and the VSC. It is operated by the VSC system, which regulates a brake fluid pressure. The steering cooperative control function is also available. The VDIM is able to perform comprehensive management.
(e) Conventional brake control systems begin to control either the braking or motive force in order to stabilize the vehicle motion when it becomes unstable due to loss of tire traction. In contrast, in order to maintain stable vehicle control, the VDIM commences controlling the brake and steering systems in accordance with changes in balance before the vehicle becomes unstable. As a result, smooth vehicle control is achieved.
(f) Conventional brake control systems manage all related functions, such as the ABS with EBD, BA, the TRAC and the VSC independently, according to the vehicle dynamics. In contrast, the VDIM provides smooth control by seamlessly integrating all those functions.
Key acronyms:
ABS - Anti-lock Brake System - The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking on a slippery surface.
EBD - Electronic Brake Force Distribution - The EBD control utilizes the ABS, and performs proper brake force distribution between the front and rear wheels in accordance with driving conditions.
BA - Brake Assist - The primary purpose of the brake assist system is to provide auxiliary brake force to assist the driver who cannot generate a large enough brake force during emergency braking, thus helping to maximize the vehicle's brake performance.
TRAC - Traction Control - The TRAC system helps prevent the drive wheels from slipping when the driver depresses the accelerator pedal excessively when starting off or accelerating on a slippery surface.
VSC - Vehicle Stability Control - The VSC system helps prevent the vehicle from slipping sideways as a result of strong front or rear wheel skid during cornering.
Anybody know anything about this?

8. SERVICE MODE
(a) VSC operation can be disabled by operating the
intelligent tester.

This would seem to indicate it can be turned off through the DLC3.
Old 11-20-07, 06:18 PM
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Here's a diagram also from the service manual that works with all the words above to help explain the operation of VDIM:



Javier
Old 11-20-07, 06:29 PM
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Turning off the TC/VSC is like opening the gates to heaven.
Old 07-19-09, 08:22 PM
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Originally Posted by llamaboiz
Turning off the TC/VSC is like opening the gates to heaven.
^^^^^^^^ ROFL ^^^^^^^^^^^^

The gates have beeen OPEND!!!!!







Old 07-20-09, 07:39 AM
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ABS - Anti-lock Brake System - The ABS helps prevent the wheels from locking when the brakes are applied firmly or when braking on a slippery surface.

For ABS to work effectively you need to stay on the brakes hard without letting up or pumping.

EBD - Electronic Brake Force Distribution - The EBD control utilizes the ABS, and performs proper brake force distribution between the front and rear wheels in accordance with driving conditions.

When the braking system senses poor traction on one wheel it will divert the braking power to other wheels that have traction (Front to back).

BA - Brake Assist - The primary purpose of the brake assist system is to provide auxiliary brake force to assist the driver who cannot generate a large enough brake force during emergency braking, thus helping to maximize the vehicle's brake performance.

The average person's normal reaction when making a panic stop will release or pump the braking power/pedal (Slightly) when the ABS kicks in and the car seems like it is not stopping. This system will apply the max pressure when the system senses a panic stop (Even if you let off the pedal). Some people think there is something wrong or that the system is unnecessarily stepping in.

VSC - Vehicle Stability Control - The VSC system helps prevent the vehicle from slipping sideways as a result of strong front or rear wheel skid during cornering.

This system will step in when it senses the vehicle is about to go out of control (slide). Again, some people think this system is too intrusive because it will disable the throttle and pulse individual brakes separately to keep the vehicle going straight.

VDIM - Think of this nanny as a cop. It makes sure all these systems play nice with each other. It will set priorities when several of these systems are triggered at one time, otherwise they will be conflicting with each other. My 4Runner does not have VDIM and some pretty weird things happen when several of the nannies are triggered at one time.

Example - I have a highway exit (A regular street corner off the highway) that has a bump just before the turn off. To make this turn you have to brake hard from the fast moving highway and then you can't avoid the bump as you are turning. The ABS/VSC/BA all trigger at the same time. The BA is triggered by the hard braking, the ABS/VSC and possibly the EBD are triggered by the bump (tire will loose contact with pavement because of the big bump). The first time this happened, I over shot the turn because the ABS stepped in and allowed the vehicle NOT to stop in time for the turn (Not a good felling!). Without VDIM the only way to make this exit is to not be on the brakes when you hit the bump. With the VDIM, I can attack this turn without any problems. The system controls the situation and the VDIM controls the systems so that it seems like there is no bump at all.

Some people feel that these systems are too intrusive. The fact is they are life SAVERS when crazy situation come up. Sometimes you may not even be aware of a bad situation that could have cause an accident or loosing control! I once thought that a very good driver could perform better then these nannies. It has been proven, by professional drivers, that this so NOT so. Testing has shown that when these systems are set at the minimal intrusion setting they can get better track times (In stock HP cars).


Koz
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