Michael-MA Posted February 4, 2007 Share Posted February 4, 2007 There are a few post about how effective the AWD function is on the IS 250 and the talk usually turns to tires, but what I want to know is: when is it active and when is it not (i.e., 2 wheel drive). Any help would be greatly appreciated. Here is my understanding: The "snow" switch only makes the car start in 2nd gear, so it has no value other than from starting from a stop. Once at speed, the snow function does nothing for you. The VSC function applies breaking to the appropriate wheels to keep the vehicle stable and pointed in the direction steered. This is not all wheel drive however. My question is: How do you know when AWD is active? Is it only when the indicator light comes on in the dash, i.e., only for a split second at a time? Is it when you hear a beep as I did when I made turn in snow and the vehicle slipped slightly? In other words, is the car in AWD only for split seconds, or does it remain in that mode once it has sensed a slip of the tires? Thanks to all for any light that can be shed on this subject. Quote Link to comment Share on other sites More sharing options...
Rx330driver Posted February 5, 2007 Share Posted February 5, 2007 the car is always in AWD mode. No matter what conditions you are driving in, it is full time awd. Quote Link to comment Share on other sites More sharing options...
Michael-MA Posted February 5, 2007 Author Share Posted February 5, 2007 the car is always in AWD mode. No matter what conditions you are driving in, it is full time awd. Interesting. The dealer told me the car was rear wheel drive except when it needed AWD. They said that is why the mpg is not much different than the non AWD models. Thanks for the clarification. Quote Link to comment Share on other sites More sharing options...
Rx330driver Posted February 5, 2007 Share Posted February 5, 2007 at least i think so. the brochure says its full time awd. it makes sense to me that there is some mileage difference though, however small. There is a 2 mph difference for each category. IF IT ONLY worked when the car slipped, wouldnt there be no difference at all? because how many times does your car slip each day? Quote Link to comment Share on other sites More sharing options...
Michael-MA Posted February 6, 2007 Author Share Posted February 6, 2007 From the Lexus Website: "With this drivetrain engine power is automatically routed to the front and/or the rear wheels as necessary to provide optimum traction." What does "as necessary" mean? Quote Link to comment Share on other sites More sharing options...
Rx330driver Posted February 6, 2007 Share Posted February 6, 2007 well okay. its full time awd, which means its basically a 50/50 power distribution between the front and rear wheels. I think if you do get into a slip, it will correct it by using the front wheels if necessary, or any wheel that has traction. this may sound like regular traction control, but traction control only brakes individual wheels. Quote Link to comment Share on other sites More sharing options...
ajmtbm Posted March 4, 2007 Share Posted March 4, 2007 i remember reading somewhere (not sure where), that its 70% rear and 30% front all the time, and it adjusts additionally as needed. there is a light on the dash that illuminates (looks like a car with skid marks behind it) when it detects wheel slippage. when this happens i assume it is adjusting the front/rear mix. Quote Link to comment Share on other sites More sharing options...
seohenning Posted March 5, 2007 Share Posted March 5, 2007 The car is not in 50/50 at all times... however the AWD can power a 50/50 ratio at "any time" depending on road conditions. I believe you are correct on the 70/30 split rear to front during normal driving conditions however I am not 100% sure. Regardless of ratios this AWD function allows for better handling over a two wheel. I honestly don't think you'll notice when and when it's on. That is what it was designed to do and is reflected in much of Lexus's designs, they are there but you are not supposed to "notice" them. I.E. the gradual heating in "Auto". Quote Link to comment Share on other sites More sharing options...
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