This button is for winter mode. The transmission will start in 3rd gear thus reducing wheel spin when starting from a stop in slippery conditions.
The shift button enabled you to capitalize the letter W in your question.
So that you don't shift the gear selector by accident
The transmission has three selectable shift programs: E, S and W. E is for Economy mode and should be used most of the time. S is the Sport mode and raises the shift RPMs and lowers the throttle position for kickdown. It's more aggressive. W is for winter mode and it should only be used when driving in deep snow.
The W button will be on the center consul near the gear selector, it is used for wet or winter weather as it changes the shift patterns for smoother starts and shifts for increased traction. (note): W button is on a toggle switch with an S so in fact it is a W/S button.
It's the overdrive engage button, which is like a 5th gear. It only engages when the gear lever is in 4th gear and it can be operated without depressing the clutch.
ctrl+shift+windows menu button+c then type in MaxMotives
Press the shift lock override button next to the shifter. Make sure you push it as far down as you can.
Because to press a button to shift a button is like pressing shift to press hard.
press the shift button
Hold down the shift button and |, which is the button next to shift.
You press the SHIFT button and then you press the x10 button.
"s" for sport "e" for economy and "w" for winter depending on how you want the transmission to shift for the type of driving you do.