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ABS brake activation

When coming to a stop my abs system will activate at about 5 mph. I replaced the Lt front speed sensor because of a dash light and now I have this other problem with the activation at 5 mph. I did find a service bulletin about the speed sensor that states to make sure the sensor surface is clean and that the sensor seated properly. I have cleaned the surface more then once but it is still doing the activation thing. Any ideas.

Thanks john

Check the other side as well. Remove the sensor and remove any rust that may have built up underneath the sensor on the mounting tab. Do likewise for the other side if your cleanings have not included removing any rust accumulation. You want to mount those sensors to bare metal. You may also consider applying a film of dielectric grease before installing the sensors to prevent rust from building up again. While you’re in there, also check the alignment of the tone rings with the sensors. If they are not centered well, you could get unwanted ABS activation.

This advice applies only to 2WD trucks. If you have a 4X4, the sensors are inside the hub bearings, and the only way you can service them is by replacing the hub bearings.

I have the zr2 it’s a 4wd, as i stated i have already cleaned the mounting surface. That didn’t seem to help any.

You’re probably going to end up needing someone with the right scanner to actually analyze what is going on in the system.

I do know that the low speed activation thing is something of an issue and usually turns out to be elusive in terms of diagnosis. I actually had this kind of problem once. It actually went away after I got new tires. I know that sounds a bit loopy - but I had found other reports of this on the web. My tires were of the same brand/size, but one was actually older & more worn than the other.

Of course, what I (and some others) experienced could have just been some kind of weird coincidence.

Okay thanks for the help. I’m not getting any dash lights since replacing the Lt speed sensor, I stopped buy Advanced Auto and all they could do was to pull up the old codes. So my next stop will be a brake shop.
Thanks again