To the best of my understanding, this changes the shift pattern so that the transmission shifts to the next higher gear sooner (i.e. lower engine RPMs) than normal. Sort of the opposite of a "sport mode" which shifts at higher RPMs than normal.
<B>Winter Mode</B> actually locks out 1st and 2nd gears, always starting the car out in 3rd gear. The Transmission Control Module (TCM) bases its decisions on inputs from sensors in the transmission as well as information supplied to it via the Closed Area Network (CAN), from the Engine Control Module (ECM). Among those decisions are the transmission's actual shift points. Primarily, the TCM bases shift-point decisions on the accelerator pedal position, vehicle speed, and engine speed. As far as I know, <B>Winter Mode</B> doesn't really alter shift patterns after the intial 3rd gear start. The more complex tasks are taken on by STC and DSTC.<P>I hope this helps! <IMG SRC="http://www.swedespeed.com/ubb/smile.gif"><P>-Drew<P>
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by kelly54:<BR><B>Thanks..this makes sense..I suppose it then works as an enhancement to the STC..</B><HR></BLOCKQUOTE><P>Not exactly. By starting out in 3rd gear the total <I>torque</I> sent to the drive wheel is lower which means it's less likely to spin uselessly in the snow. It does mean the car will accelerate more slowly. But a slow acceleration on the snow is better than no acceleration if the wheel spins--the car just sits there.
Winter driving mode was much more important before the advent of STC. Now, if you want you can just let the STC kick-in to prevent slippage; but without STC the only way to do that was to start in a higher gear. With manual cars this was easy, with automatics it could be more difficult. And so they came up with the Winter mode.
Ok..I just drove it this morning in very wet and icy conditions, and I felt the difference by starting off in the higher gear..the car "grabbed" the road much better than a start without "W" engaged..I now understand that the STC would be a separate feeling of traction, after I am rolling (or slipping).