I have checked have checked the sensor for broken wires or broken sensors none found. ABS module has not stored any codes either.
ABS engages just before coming to a complete stop on dry pavement,with no codes on 2006 Pontiac Torrent
Are all the tires of equal size, a matching set? Sometimes if they are not it will do strange things. It may be best to get an over view of how the whole system works and test procedures from a good workshop manual. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online
For the situation you mentioned, I think it's more likely to be a trouble in hardware.