2004 Grand Am ABS Issues

[Getalinks]

I recently have been hearing a sound in the front of my car that sounds like a manual upshifting and downshifting when I accelerate and decelerate, respectively. I don't have a manual car. I was told it might have been the wheel bearing, so I took it to a mechanic and he didn't hear anything when he checked them.

Last week, I was rearended from behind about about 5 miles and hour. No damage, but when I was driving home, my ABS light, Trac Off and Service Vehicle Soon (not the Service Engine Soon) lights all came on. They come on now at sporadic intervals after I start up the car ranging from after 25 mins of driving to right when I start the car, but once they go on they remain on until I shut the car off.

I took it to Auto Zone and had them hook it up to their computer but there were no codes. They also tested the Charging System. Then I took it to a mechanic and still no codes. Both places tried with the car and and off to test the codes and they couldn't figure out what was wrong.

I then took it to the Pontiac dealership and they told my it was most likely my Hub and Bearing Assembly and it would cost $400. (But the mechanic couldn't hear anything wrong with the bearings before.)

I tested a theory today (it just snowed) and hit the brakes. The lights weren't on at the moment and I could feel the ABS working. A few seconds later, the lights were on and when I tried them, the ABS didn't work.
Can anyone tell me what's wrong? Is it really my hub/bearing assembly or something else. I don't want to pay $400 if it's just wasting my money.

Thanks.

[Bassasasin]

Well its called a HUB BEARING SENSOR assembly... and the electronic circuit sensor part is bad not the bearing part.. Its a combination of the wheel bearing and the sensor assembly as a complete part on GMs.

They cost about 130$ and 2 hours work plus a shop likes to charge the $85 to hook up the ABS analyzer to determine which wheel. An intermittent one may be quite difficult to find.. however the right front has a tendency to rust quicker and go bad from more pothole hits and such.

I probed my ABS connector and determined which wheel was bad. My front 94' GM Park Avenue was muscled off with a bit of encouragement like a chisel..2 hours and it cleared my ABS light and Traction control.

There are some posts on internet of the work involved. It depends on wheter its your rear or front sensor thats bad as to your issues..
Do you know which is bad.. Could be just a connection to that sensor..

I think on your 2004 its a bit early for those sensors to quit.. but it is a possibility.
ABS is the best thing since seatbelts. Does your system have a indication of low tires?


Good Luck

[xeroinfinity]

Welcome to AF Getalinks.

Does sound like your HBS assembly is bad, and as Bassasasin said the right front does go out more often.

And the price is about right. They'll charge $200 for the part & the rest on labor.

My GA GT has had a bad right sensor for over a year now.
When it rains, or I spin the tires , my dash lights up like a christmas tree
I just turn off the traction control when I take off or it rains
I have two new Hub assy's, I'm just getting my moneys work out of these

I always try and replace them in pairs too.

[Getalinks]

Someone told me it might be the speed sensor. But that's part of the assembly too. (Don't know if that would affect the speedometer, but the speedometer isn't malfunctioning.) If I replace the whole assembly, would that fix the issue if it's any of the following: Speed Sensor, Bearing, etc and anything else it oculd be? Thanks.

[xeroinfinity]

yes the speed sensor is the same as the wheel hub/bearing/wheel speed sensor.
I still dont understand why they stuck all that in one unit

But you do need to make sure which one is bad by scanning for the trouble codes.

Also autozones scanners do not read ABS or trans codes.

Hope that helps!

PS- you do need to remove that link in your signature,
well no links to other forums
Or I will for you,

[Bassasasin]

Dont know on your car in particular, and perhaps someone can post the pins to check for a open ABS circuit if its possible to probe.
At least my car 94' has a connector and it probed out as an open.
If its intermittent that wont work.. Some have discovered that the wiring has failed or exposed and shorted to the frame and as I remember in the rear on a newer car did this.. The poster paid for a new sensor and still had problems.

If your inclined to check out these lines you may save some $$.
Also, I didnt know the VSS speed sensor is tied to the wheel sensor assembly but perhaps it just uses one wheel and that one is good.

I purchased my wheel hub assembly for $125.00... but had to muscle it off.
There is some web sites with the pix of taking one off I have found. here is a pix of one. http://www.elkparts.com/images/52-91...3DwwR%26sa%3DN


Good Luck

[xeroinfinity]

If the ABS sensors at the wheels have had the plug in taken off and on several times,
you can bend the pins over and have troubles.
But this would be constant with a code and your trac/abs lights illuminated.

Yes Bass, you can test them with an ohm meter, its just a pita if you dont have a garage(and heated right about now). Much easier to just scann (i'm lazy)

I have Never seen any shorts in the rear wheel areas on any N-bodies from 96+.
But the 95-98 n-bodies do have trouble with the fuel pump wire harness getting breaks and shorting out.