05 Rendezvous AWD Speed sensor codes

Have 05 Rendezvous 3.6 ltr with codes for low voltage on the speed sensor and also intermittent speed sensor voltage. Had the codes cleared last week. I had a control arm replaced after kissing a curb in the snow. Gorillas at dealership tightened the wire ties on the speed sensor wires pretty good and I think that might be the problem. Wheel bearings are just starting to sound worn car has less then 50K. How do I test the voltage going toward the speed sensors? Always appreciate the help