I had a left rear bearing growling.  Took it to a shop and they replaced the hub assembly.  When they were done, my ABS light was on.  They replaced the hub again.  No change.  They ordered an ABS speed sensor and put it on.  Light was off.  All was good.  2 days later, my ABS light is on again.  Took it back to them, with the ABS light on all the way.  They got in the car to pull it into a service bay, and the light was off.  I drove home.  All was well.  This morning I got half way to work and the light comes on again.  What the heck????????  Anyone have a clue? Cuz the mechanics don't. 

I've heard others mention some aftermarket hub assemblies have issues with ABS sensors.

Kinda sounds like they damaged the wheel speed sensor for that wheel. Or as Mike said they installed a crap hub unit and the magnetic ring in the unit isn't designed properly so the ABS can't read it to get an accurate speed signal.

 

Does the light turn on right away, or does it only come on after you start rolling?

Comes on right away is a wheel speed sensor problem. Damaged sensor, wiring, or loose connector.

Comes on when rolling is usually a tone ring problem.

i think sometimes (ive had a lot of abs problems) the sensor gets so old and dried out when they move it it kind of falls apart and they dont tell you cause theyre afraid youll make them replace it.

Got it solved. Took it back last night. Another mechanic took the speed sensor out and it had a groove cut into the side of it. So, he took it all apart and found that the dust plate at the back of the axle was bent by the first mechanic, and it was rubbing on the sensor. It also rubbed on the back of the hub and destroyed the magnetic ring. Needless to say, they are replacing everything again and I'll be good to go.

 

Thank you for your thoughts everyone.