AWD question about when power is sent to the front wheels

[CDNicecube]

Hi

So I have been enjoying my AWD EX35 (2010) for more than 2 years now. We get some really bad snow storms up here and again today, got another one. I was driving back and forth from the ski hill when a thought came: I know when the car slips significantly, the VSA ( dynamic stability assist) light goes on (skid marks light) and we can feel the rear brakes working and the engine power being cut off. An idiot light on the dash board blinks when this happens.

But can power be routed to the front wheels WITHOUT this light blinking? Is the VSA system independant from the ATTESA AWD system? Or will the VSA light always light up when power is routed up front? Because the only time i see the light go one is either when turning a corner a little too fast or floor it on a snow cover road.

Anyone knows?

ice

[Teknical]

Yes I think it is a different system from the traction control. I mainly notice the AWD coming on when I go up steep gravel or muddy hills off road.

[CDNicecube]

I surely hope so. Because if the vds light is also an indication that the front wheels are being called into action, then they are seldom used when driving in a traight line (in my case) on snowy or slippery roads. I hope these two systems are mostly independent (vsd and awd) from each other (helping each other only when required ); if not what is the advantage of the awd ATTESA system vs the rwd version of the EX?

Edit: checking the manual didn't help.

[TimGinCentralNJ]

Funny...I was just re-familiarizing myself with the ATTESA-ETS system this past weekend. If I recall correctly, the "skidmark" indicator (which--depending on the severity of the event may also indicate you should check your underwear..heh heh) indicates there is a 5% or greater rotational difference between one rear and front wheels, which kicks in the ABS braking system--both to act as a "posi-traction' between the left and right rear wheels--and to begin moving torque to the front wheels.

I believe the VSD and ATTESA systems are very much independent, as VSD can be temporarily disabled, leaving only the "electronic rear traction control" engaged, essentially giving you a rear limited-slip differential and rear-to-forward transfer of torque based upon the degree of slippage. Also, remember the ATTESA system automatically starts from a dead stop with a 50/50 torque distribution every time.

Hope that helps a little,
Tim G.

Here's a good read which explains it pretty well: http://en.wikipedia.org/wiki/ATTESA

"To control the ATTESA E-TS system, there is a 16-bit computer that monitors the cars movements 10 times per secon"d to sense traction loss by measuring the speed of each wheel via the ABS sensors. Also a three-axis G-Sensor mounted underneath the center console feeds lateral and longitudinal inputs into a computer, which controls both the ATTESA-ETS 4WD system and the ABS system. The computer can then direct up to 50% of the power to the front wheels. When slip is detected on one of the rear wheels (a rear wheel turn 5% or more than the front wheels), the system directs torque to the front wheels which run a non-limited slip differential. Rather than locking the AWD in all the time or having a system that is "all or nothing", the ATTESA E-TS system can apportion different torque ratios to the front wheels as it sees fit. This provides the driver with an AWD vehicle that performs like a rear wheel drive vehicle in perfect conditions and can recover control when conditions aren't as perfect"