?ABS
 

My 1994 LSI makes a grinding noise with a pulsating brake pedal at about 2 mph when coming to a complete stop. No dash lights are on. Brakes, tranny, seem fine otherwise. Any suggested diagnoses/fixes much appreciated.Thanks.

Re: ?ABS
 

Cracked or broken/chipped tone wheel. It's sensing a longer period without a tooth so it thinks the wheel is locked. Could be a dirty sensor as well, but I'd inspect the tone rings first.

Re: ?ABS
 

Thanks, and I learned what a tone wheel is.

Re: ?ABS
 

Can you feel a warped rotor at under 30MPH? Or only over 30? How would he know what wheel is causing his problem ? Is there an easy way to tell what rotor is warped?

Re: ?ABS
 

This has nothing to do with rotors.....

There is no way to tell which wheel other than by "feel" other than visual inspection. With a SSM, you may be able to monitor individual ABS wheel speed sensors and be able to pick up the one causing the issue but I don't even know how powerful the SSM is other than Engine and trans monitoring.

Re: ?ABS
 

if you have a voltmeter you can monitor the ac voltage produced by the sensor while spinning the wheel by hand. could also be a more worn tire or even a tire that is low on air. had a subaru a few weeks ago doing the same thing and just had a low tire.