My son has a 2005 Grand Prix and the ABS/Traction Control light comes on occasionally.... it is not always on...... I have replaced the front wheel hubs, and my scanner shows the mph of the front wheels..... so what else should I be looking at?

Get the codes.

I have....it'* showing no signal from Left Front...... I've replaced wheel bearing and it still does it..... I guess I will try replacing it again..... even though it'* showing the proper speed from the both left front and right front.

What is the actual code?

C0035 I'm gonna replace the bearing again and see if it corrects the problem.......

Stay away from the cheap chinese junk. They are known for ABS issues. Timken is the way to go.

The Hub Bearing is FMK from Britain, not Chinese

I would stay away from the cheap stuff and make sure the wiring is good.

So why is it showing the MPH reading on both front right and front left on my GM Tech II if the wiring is bad?

Intermittent. Look at the freeze frame.