Abs

Hi there I have a kia sorento.
Abs light not on so no codes.
Brakes fine high speeds until I hit 5 miles a hour to
a stop the abs comes on a buzzes.
Does anyone have any ideas or had the same
problem. Garage reckoned abs pump, some people
have said brake sensors.
There no codes up so you wouldn't know which
sensors.
The only thing is a year ago there was a new wheel
bearing put on the front passenger side of the car.