Recently my STS started having the following problem with the traction control system.

I am taking my car to the dealer either this week or next week for this and a couple other problems for warranty work.

I'm wondering if anyone knows what may be causing this problem and if there are any TSB's relating to it.

My STS has never ever done this before. I drive a lot on the highway sometimes and usually at about 80-90 MPH.

Last Tuesday when I got on the interstate I got up to 80 MPH and the DIC said traction control active and I could feel that I had a big loss in power and a slight pull to one side.

It kept doing it any time I got over 75-80 MPH so I ended up turning it off.

Since then I had to go out of town for the weekend and I put about 500 highway miles on my car. I noticed that as soon as I hit 75-80 it comes on, I lose power, and the car sometimes pulls one way or another (random direction).

I also noticed that it seems to only come on when I am pushing the gas. If I let off the gas it turns off, then when I press the gas again it comes back on. I dont have to press the gas hard for it to come on, I only have to press it hard enough to keep the same speed.

Needless to say I feel that this could be very dangerous. Luckily it has not rained bad recently and when I turn it off it stays off and doesn't kick in the stability control or something.

I did get all brand new tires about a month ago, but it did not do this until last week. So I dont think it is related to that.


I would love to know if anyone else know why this is doing this or could give me some suggestions to give the dealer.

It's something to do with the staggered tire sizes.

What do you mean? I have the same size tires on as before and they are the same size as is upposed to be on there.

And I drove for two weeks or so with the new tires in it and it was fine. Of it is somehow because of the new tires can the dealership fix it? How?

It's the tires. I replaced my tires front/rear at different times. Either one is off balance (a lot), or the sizes are off (which might not be your case).
This tells the traction control the speeds are off. Mine did the same exact thing. It was the most annoying thing in the world, but I knew it was because of the cheap tires I put on front, so there was no reason to bring it in. After a month the tires adjusted and the problem went away.

snum1fan - If you do not have TPMS, have you checked air pressure in all 4 tires?

A bad wheel-speed sensor is the most likely cause. Let the dealer figure it out.