DSC use
 

Could someone expand when and when not to engage. If I remember right the dealer salesman indicated that it is for snowy/foul weather? I know it has something to do with traction control, and when depressed a 4x4 indicator light illuminates on the dash. ......TIA

For 90% of the time, don't touch the button. By default when you turn the car on, DSC (Dynamic Stability control + Traction control) is fully on. When the system is on, no lights come on the dash. When the system is actively working, the symbol flashes.

In deep snow, sand, and/or if you feel like doing some enthusiastic driving, push the DSC button which shuts DSC off. The light will come and stay on the instrument cluster, meaning it is off. The system is in reduced function, with only Traction control, so larger slip angles are permitted.

If you hold the DSC button for about 3-4 seconds, this shuts DSC and Traction fully off. If you really feel like being naughty (or if you're auto-x'ing), this is the mode to be in.

Do a search on this forum.

It should always be left on for optimum control and safety, except for the following situation. If you ever find yourself stuck in snow and unable to get out, try turning it off because sometimes spinning the wheels will enable you to burn down through the snow/ice to the point where you will find some traction (if DSC is on, it won't allow you to spin the wheels).

I am actually not so sure that is true. I tried at the last auto-x and after holding the button down for a LONG time, the DSC light went out. On that run, DSC was in full force and effect. I asked the guy working as the starter who is a BMW Master Tech. He told me that holding the button down did NOT shut the system down entirely as in other models.

To the OP...all of the advice given in this thread is excellent and accurate!

I always leave DSC on. Just now I was driving on my road which is packed, slick ice with a continually building layer of fresh snow on it. It's damn slippery, but it's ok with DSC on and basic knowledge of how to get out of a skid. I tried turning it off and the car was all over the place.

I have a 2003 330xi. Pushing the DSC button once supposedly raises the threshold of DSC intervention. Holding the button for about 10 seconds takes away the component of DSC that cuts engine power, but it keeps the individual wheel-braking part on.

Holding it down for 10 secs or so (until the DSC light goes out again) activates that "Half-mode" described in the E53 X5 forum. Basically, DSC will not intervene on the throttle, but will brake (only) the wheels that are spinning. And this mode cannot be disabled until you restart the car.

if you hold it, it turns off the traction control. but when i hold mine, nothing happens.

and my dsc icon never flashes. does that mean dsc was never needed when i drove?

Apparently, there was no visual distinction made between DTC only and both DSC/DTC off modes on the X3. Apparently, its there though. See one of the posts made:

http://www.x3world.com/x3-e83-forum/...appens-2.html?
If DSC never flashes, it means it was never needed. With xDrive, BMW made DSC even less intrusive, so that xDrive can do most of the traction and handling needs, with DSC stepping in only as a last resort. It is almost never needed on dry roads or even wet roads. Usually for me, the X3 is way out of line before DSC will step in.

i guess these SAVs handle really well. i had an e90 330i and when it's raining, starting from a stop, the icon always flashes. never happens with the X.

I read that thread you referred me to. There was nothing in that post that says that DSC is able to be totally defeated. I know on the e46 it could be, but so far as I can tell it can not be disabled totally on the X3.

At the last auto-x here, I experimented with the different modes. One push on the button and the DSC light comes on. Traction control was defeated. The car is able to reach incredible slip angles, even spinning its tires in a straight line under acceleration. It did NOT intervene under braking, although dynamic brake control continued functioning (it is a different system). Holding the button until the DSC light went off returned the X3 to full DSC...under acceleration and cornering. I might even have a video of the test somewhere...

I have never seen anything in any official literature, or from any BMW tech, that supports that holding the DSC button futher deactivates DSC. In fact the shop foreman at South Bay BMW, who is an avid club racer, told me that holding the button does NOT shut the system down like it does in the e46. One of his co-workers confirmed. My personal experience further supports their opinions...Push DSC to shut it off and allow wheel spin. Hold the button and the system turns back on.

That being said, I personally think xdrive is absolutely unbelievable. It provides an unbelievable amount of traction and feels amazing during performance driving. It is hard to imagine buying another car without it.