Olitho

I daily drive a 2004 Cadillac CTS-V.

For a couple of months when I am driving a feel a momentary high frequency shudder in the car for about 1/2 a second. If I am in cruise control it will drop out of CC. The car also feel so pull for a moment to the left.

This problem tends to happen the most it seems while cruising on the highway. I felt it to be associated with the AbS system, but that seemed implausible while just cruising. But I the past two weeks twice while braking it did the shudder while my foot was on the brake pedal. The pedal vibrated and felt to push back a bit like when in ice mode. The highways in SoCal are always dry and warm when this is happening. This event occurs now every few mile of driving.

Any ideas?

96CollectorSport

Oli,

I would try an ABS module - there are used ones on E-bay for under $200. It's the only thing that controls your brakes other than your foot.

Bluefire

These are the classic symptoms of the Steering Wheel Position sensor going bad. SWPS sends momentary bad data to the EBCM, EBCM "thinks" you're sliding and applies one of the front brakes to "correct" the slid.

Check your codes but, that's where I would look.

Olitho

Good idea. I will turn of TC while I am driving and see if that diminishes or eliminates the problem. That will help me trouble shoot.

Olitho

That is a good idea as well. I already have a spare for the C5 Z06 race car I have. I need to check and see if it is the same unit.

Interestingly enough, I don't get any codes on the DIC when this occurs.

Bluefire

Can you pull the connector off of the SWPS to see if it demonstrates the same failure mechanism?

Bill Dearborn

It could be a loose wheel bearing causing slightly erratic wheel speed signals. The EBCM checks for those and will throw a code if they get to erratic but when it is just starting to go bad the EBCM may not flag the error. My Tahoe has the GM truck ABS problem. Where ABS would activate when making stops like you are making. Since mine was one of the few AWD models in 03 it also has traction control and my first indication of a problem was when TC control cut in and brought the Tahoe to a stop as I was pulling away from a stop. The fix was to clean corrosion off the ABS Sensors which aren't part of the hub. Have to do that about every two years.

Bill

mgarfias

I'd pull the ABS fuse and see if the problem goes away. If not, then you have some kind of mechanical issue. Otherwise, i'd hook up a scanner and log data from the ABS computer. look for some sensor being whacky at time of shudder/pull.

Olitho

Another good idea!

rocsvette

I had similar problem in my C5, went the ABS repair mode and problem still there. It was the SWPS. First try cleaning contacts because that sometimes is the issue. If thst doesn't work you need to replace the sensor itself.

96CollectorSport

Oli,

Check out this link

http://www.cadillacforums.com/forums...r-install.html

Olitho

Thanks Joel.

Olitho

I drove around today with traction control disabled and the problem persists.

Tomorrow morning I am pulling the ABS fuse to see if that eliminates the problem.

FAUEE

I was thinking you might have a tire out of balance or a slightly bent rim.