ABS or Transmission Issue? Help Needed!

There is a new problem that has been devolping in my 2003 3.8l Impala.
Sometimes when I take off from a start the car makes a loud hummming noise and a light on the information center comes on saying "Traction Active". This will happen for a few seconds then stop. Now yesterday it was alittle worse, after it did what I described above I then hit the brakes and the brakes felt bad or they had like a grinding feel come from them for a few seconds. I did check the level of the transmission fluid and it was low, I added more into it. But it still did it this morning. Would this be the ABS or transmission?:shakehead

This sounds like ABS. The humming noise is likely the ABS system. The usual culprits are bad wheel speed sensors. Each hub has a sensor built in, to change the sensor the hub must be changed.
Before changing hubs, carefully examine the wires going to each hub. Unplug and check the connector for corrosion. Then look for kinked or broken wires as far as you can see. Pay close attention to anywhere the wires go near suspension parts, or parts that move when turning the steering wheel. Start with the front wheels, problems are more common in the front.

Thanks, I will be checking that out this weekend.

Here is an update on the car, when I almost reach a complete stop I hear what sounds like a pump activating from the front of the car and the brakes pedal feels real rough. This happens when braking less then 10mph and last for about 2-3 seconds. Now I havent had a chance to pull the wheels off over the weekend to check the ABS sensors. I will do this tonight after work. I guess my question now is, is the ABS sensor cleanable? Since it can only be replaced by changing the whole hub out

Well I have taken the wheels off to inspect the abs sensors and everything looked ok, but the sensor seems to be deep inside the hub and I was unable to see if maybe it was damaged. But I did notice the cv axels leaking grease. So now I need to replace them.:banghead::banghead::banghead:
Is there a way I can test the abs sensors to ensure they are working or bad? I dont want to replace the bearing hub If it is not broke. Could it also be the ABS pump/box/computer (not sure of the name)???









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A scan with an abs function scanner it the most accurate way to diagnose this as it reads wheel speed inputs from each sensor and you can see what is going on. You could check the speed sensors at the wheel connector for the proper restance about 1150 ohms for the ft and 1050 for the rear, but even if they pass one could still cause the problem.

your 2003 impala has a TSB about sensor wire failures ..that a kit is available to correct the factory harness that was found to be defective..this harness is routed and supported differently...to avoid damage..


with your description however I agree to find the defective sensor would be to have the scanner check for signal in operation the verify the failed one...or you could just replace both front hubs...

since I don't have the spec's on this one I can not say exactly what a/c voltage you would get if you rotated the hub and measured for the voltage...doing this I would guess the hub that reads the lower is the defective hub....low sensor voltage output will cause your problem at low speeds..

your grease leaking looks like you need to tighten the clamps...if these had too much grease installed in the boots this would cause them to ooz out...I know of owners packing these as a routine maintenence item... which is not the norm...

Here is an update on the car, when I almost reach a complete stop I hear what sounds like a pump activating from the front of the car and the brakes pedal feels real rough. This happens when braking less then 10mph and last for about 2-3 seconds. Now I havent had a chance to pull the wheels off over the weekend to check the ABS sensors. I will do this tonight after work. I guess my question now is, is the ABS sensor cleanable? Since it can only be replaced by changing the whole hub out why don't you just unhook the abs unit all together and have the real brakes back again,just because the dash lights are on and the sensor is bad does'nt mean the wheel bearing is gone,my car has 2 sensors gone so what i did to get rid of the pump acting up and feeling it through the brake pedal like the pump is on just open up your hood,disconnect the black box on the abs pump below the brake fluid reservoir slide the outside of the box to the left after you break the clips that hold it in place then your car will work fine,next unhook your neg battery terminal for 60 secs to erase the codes for anti lock traction control and brake lights,if it don't clear the code then disconnect it again for 30 secs or more and reconnect till it clears the codes,you may have to do it 4-5 times in row to fix the lights coming on in you dash

with your description however I agree to find the defective sensor would be to have the scanner check for signal in operation the verify the failed one...or you could just replace both front hubs...
your grease leaking looks like you need to tighten the clamps...I know of owners packing these as a routine maintenence item... which is not the norm...

A Tech II or other ABS capable scan tool can tell you which sensor is bad. As jcAT said, fronts are bad more often than rears. The sensor within the hub can be bad, but the hub itself can be good. The sensors cannot be replaced without replacing the hub, unfortunately.

If your CV boot is not torn, just cut the clamp, repack the bearing with Cv joint grease, and put on a new clamp. I used two screw clamps on mine 15K miles ago, and it hasn't leaked a bit since. It's not a hard job at all, and much cheaper than a new axle.

Thanks for all help on the ABS. I will try and get someone to scan it soon. As for the CV axel, I replaced it today. Bought a new one from autozone for $69 dollars. That way it gave me a chance to check out the hub which looks fine on the drive side. Thanks all!! now I have another issue, Im going to search this forum for a answer before I make a new thread.

j cAT,

Would this be the correct wire harness to replace for the ABS Brakes?

Right Side: 10340313
Left Side: 10340314
www.gmpartsdirect.com (http://www.gmpartsdirect.com)

Also, is it a good price? It doesnt describe the part very well, but this is something I came across when I did a search.

j cAT,

Would this be the correct wire harness to replace for the ABS Brakes?

Right Side: 10340313
Left Side: 10340314
www.gmpartsdirect.com (http://www.gmpartsdirect.com)

Also, is it a good price? It doesnt describe the part very well, but this is something I came across when I did a search.

since this is a TSB on your vehicle . call dealership and with your vin # the parts department will give you the GM part #'s you need..then you can search on the internet for a good deal..

where on the net can i seach for a good deal on a iss shaft for a 2005 chev impala,bought a new one on ebay,went to dealer to get it put on and come to find out it was a new one to fit a buick regal,now my old one they put back on with greasing it has my steering gone way loose with lots of lash and steering play,it was not there before they disturbed the shaft,thanks

start new posting with your issues ...start from the begining to what you have now ..