99 Alero

Whenever I start the car and put in gear the ABS & Trac lights come on along with a loud warning "bell" or "ding". It's just one ding and then the lights stay on the whole time.

Bad wheel hub assembly? Are there only the hub assemblies with ABS sensors in the front or do the rear wheels have them too?

Could it be anything else?

Needs to be scanned with an abs function scanner for a proper diagnosis.