Whats up

My ABS light comes on after i go pass 20 km/h
I have cleaned the sensors the light went off for about 10 Ks

Then i took out the positive battery terminal
I drove the car for 70 Ks put my car off then
Started it again went pass 20 Km/h the light
Came back on

Please help so i can sort out this problem

Do you think that is could be

1: sensors
2: ABS control unit

THE LIGHT ONLY COMES ON WHEN I DRIVE OVER 20KM/H