I had shock absorbers put on when I got car back the Trac off light was on and so was the abs. What could cause these to come on without moving car? Diagnostic test said both wheel speed sensor.
Traction control is actually a function of the Anti-lock Braking System. Both work by measuring the speed of the wheels, and when one wheel is spinning considerably faster than another, the brakes for that wheel are applied in pulses. Usually, when those systems fail, it's because something is wrong with one or more of the wheel speed sensors. The wheel speed sensors are part of the hub that the tire mounts on.
The wires that connect to the wheel speed sensor may have gotten broken, or they may not have gotten plugged back in. The shop that replaced your shock absorbers should be able to diagnose and repair it, and they should probably do so for free, since it's almost certainly their fault.