[s-cars] pulling codes - link to write up

[Tom Mullane]

Couple o' comments on this:
It is not uncommon for a failed CV boot to throw enough grease around so
that some gets into the triggers on the outer joints.  If the triggers are
packed with crap (or a Brooklyn tumbleweed) the ABS light will come on.

On the sensor installation, I often see marks on the tips of the sensors
from rubbing on the triggers.  I've tried to "seat" the sensors then pull
them back a smidge to give a small air gap but this always results in the
"stutter" as the car comes to a stop.  Now I just bury them.  On both my
C5's, the front ABS sensor tips are grooved from contact with the triggers.
This predates any hacking I did on the cars.

Tom 

Date: Wed, 15 Dec 2004 15:17:35 -0500
From: Keith Maddock <keith.maddock at gmail.com>
Subject: Re: [s-cars] pulling codes - link to write up
To: Theodore Chen <tedebearp at yahoo.com>
Cc: s-car-list at audifans.com
Message-ID: <933ee18904121512171fe976b0 at mail.gmail.com>
Content-Type: text/plain; charset=US-ASCII

 Theodore Chen <tedebearp at yahoo.com> wrote:
> 
> --- Keith Maddock <keith.maddock at gmail.com> wrote:

> > Check to see if it always comes on when you exceed a set speed.
> > or
> > Check to see if it always comes when you decelerate back down to a set
speed.
> 
> i don't know about a set speed.  i do notice that it comes on shortly
> after the car gets going.  it doesn't come on when the car is just sitting
> with the engine running.  

OK - I'd lean towards that being a specific speed - but would be
interesting if you could verify that.

> i checked the wheel sensors some time ago.  i cleaned them and pushed them
> back in, but i didn't do them all at once (i did it when i had the wheels
> off for one thing or another).

Perhaps one has backed out since then?
>
> > Generally a fault that shows up after a certain amount of time running
> > will be a wheel speed sensor fault - something that the system must
> > test dynamically.
> >
> > If the latter of the two checks above is true, then you might have a
> > wheel speed sensor that has backed out of its press-fit slot.  Push
> > then all back in as hard as you can and then see if you still get the
> > code.
> 
> push the sensor flush against the ABS reluctor wheel?

Well, push the sensor as far as it will go in it's mounting sleeve -
it should not allow the ABS sensor to touch the tone ring, otherwise
you will damage your sensor - there has to be at least some air gap
between them.
> 
> > also check for Brooklyn tumbleweed I guess , or any other thing that
> > might be interfering with the WSS:-D
> 
> brooklyn tumbleweed?  you mean trash?

I think Serge used that term in reference to plastic bags blowing around :)

Another idea is that it could be the result of some system self test. 
Lots of systems will test the solenoids and motors at startup, however
some will wait until you are going a certain speed - the though there
is that the extra road noise will mask the (sometimes odd and
unpleasant) noise of the self-test.

In that case it could be just about anything.

If you are certain all the wheel speed sensors are fine, the next
easiest step might be to try to find an ABS controller module you
could borrow to see if that makes the problem go away...

Cheers,
Keith