ABS Sensor problem

I have a 204 s-10 blazer 4x4. The rt front wheel sensor i damaged changing the bal joint. I replaced it with an AutoZone sensor. Now I'm having a problem with the ABS engaging when I use the brakes. Do I need to reset the codes or do you know of a fix? Thanks

At what speed does the ABS pump come on when stopping? Is it below 5 MPH or any time you brake?

Yes, it is under 5 mph.

Most likely rust between the sensor shim and a front wheel bearing/hub assembly. If rust is excessive, it pushes the sensor out, away from the tone ring, and the sensor can not generate sufficient voltage. Both surfaces of the shim and the hub where the sensor mounts, need to be cleaned and then reinstall the sensor.