ABS Sensor

After replacing the hubs on my trailblazer and driving it for a bit, the ABS light came on. I know the sensors are on the new hubs. Any idea why it would be on? I have a code reader but apparently it does not pick up the ABS codes??

You said it, it must be scanned with a abs function scanner to pinpoint the problem, make sure all the connectors are in place first of course.

Ok had the codes all checked. Seems like it is all related to the right sensor...

co221
co281
co222
c0223