Got an interesting situation I could use a more technical explaination and suggestion with my LS on ice.

With the recent ice storm I have experienced a first. Was backing out of the garage onto a small patch of ice on my driveway. Everything was normal till both rear tires were on the ice and then they started to spin out of control. Braking was useless, had to shift the transmission to neutral to get them to stop spinning. Happened in both Drive and Reverse.

Tried it with the TRAC off and no effect, still just spun away and left dark black streaks from my snow tires on the ice. I got out and pushed the car onto a patch of concrete and then was fine.

I wonder if I have a TRAC problem?

 

Those are the days when I take the GX470 to work. Of course, when ice is involved, then I get to see all 4 wheels spin!! Be careful out there!

 

Yeah, I hear you about that GX. Actually was just going out for a quick bite to eat with my spouse on the holiday. Had it happen one other time but wasn't that observant like this time.

It may not really be a problem, just the way the TRAC system works and I hadn't really paid close attention before.

 

Aggie - Did the traction control and stability work normally after you got out of the driveway? I have had my rears spin in reverse on the driveway if it's icy out. I am pretty sure ABS will not engage under 5 mph forward or reverse. Maybe traction and stability work the same way? If it works fine out on the road, I'd just wait and have it checked next visit.

Bruce

 

I THINK TRAC does a diag when you reach 5-12Mph or so... so if you never got up to that speed... the diag was never done, and it doesnt work until it tests itself if im not mistaken.

 

I agree. Just coasting along, TRAC doesn't work, but then again it doesn't wouldn't work too well sliding sideways anyway!! I wonder if the BMW Park Assist would work in this instance?!

 

That seems to explain what happened as I was just creeping along at 1-2 mph due to the ice on the driveway. It's absolutely flat and retains water so is always slippery.

Maybe I need one of those 4-wheel dolly's that you see at LeMans and other races to move the car in/out of the garage. Then line it up to launch down the drive onto the street. Now, if I can get one of those old steam catapults from my Navy buddies I can improve that 0-60 time too.

 

Aggie, let me try to explain this to you. From everything I've heard about your situation it seems that nothing is wrong with your car. The traction control system is designed to give power to the wheel with the least spin, a driving wheel that is. So since both your driving wheels were on the ice and spinning out of control the trac is useless. The fact that applying the brakes to correct the situation was puzzling to me too, but here is my take. The brakes when applied normally send about 75% power to the front and 25% to the rear, ABS is not an issue here again due to speed. The rear wheels will always be driven until your torque converter locks up, meaning that if you let your foot off the gas at a stop light away she will roll. Next time this happens I suggest you get off the gas and while holding the parking brake release apply the parking brake (doing so allows you to pump the brake without locking it up with the ratchet) If this does not resolve it you have a problem with either a too high idle or faulty brakes. I hope this helps.

 

What your saying makes perfect sense, however, the car has speed sensors in the front, and should have realized that the car was not really moving, and applied the rear brakes.

Also, even if applying the brakes doesn't work, the car should have cut off engine output if needed. and this was on the VSC system since 98, and it has since improved even more on + '01+ models.

But i think the trac system isn't operable until you reach a certain speed, so it can do its diagnostic test, then its smooth sailing from there.

 

My garage is at the bottom of a hilly driveway here in Pittsburgh. TRAC, Blizzaks, Nokians...doesn't matter..the LS430 just won't go up the driveway in bad weather. To be fair, neither did my old S Class Mercedes.

My next vehicle will be an AWD vehicle. In the real world, they can sell TRAC till cows fly but in the end rear wheel drive cars just don't go anywhere near as well (if they go at all!) on snow and ice as compared to AWD vehicles.