My ABS has been acting up for a couple of months now. When I go to break I get the shuddering like it's kicking in on ice. But there's no need for it to activate because I'm breaking normally. Usually at lower speeds when coming to a stop. But this is very dangerous because I don't stop as quickly as I should.

Now I've had both of the front wheel hubs and both of the front ABS wiring harnesses replaced....and it's still doing it! As soon as I drive down the block, the lights come on: "SERVICE TRACTION SYSTEM" on the message center, and "ABS Off" and "Trac Off". I really need help!!

 

You need a scan tool that can read the ABS codes and see what code it's giving. Or the other option is a scan tool that can do a small data log recording data off all 4 wheel speed sensors, play the data back frame by frame to see which one is out of sync. Could be a rear speed sensor. But if you find one not in line, lets you know which wheel to inspect.