90 325i ABS light

My abs light is coming on but only when i drive the car about 100 ft or so. Light will come on and stay on but does not come on when i crank the car and leave it idling no matter how long it does so. I recently had work done to replace the hubs and am wondering if a mistake was made. Are there 2 different types of hubs for this car? One made for cars with abs and another for this same car without abs. Is abs standard for this model? Since it only comes on once the car is moving it makes me think its not a relay or sensor gone bad but something to do with the wheel speed sensors instead. Any suggestions?