Toyota Repair Problems? Ask a Mechanic for Answers ASAP
A wheel speed sensor will not cause a hydraulic problem or an issue depressing the Pistons into the caliber. If you are having a problem with the brake calipers dragging or applying slight pressure to the rotors overheating the rotors then there probably is a problem in the master cylinder or possibly the caliper pistons themselves.
Normally no it will affect two wheels diagonally from each other. You may want to consider trying to see if the caliper pistons will release back into the caliber. If you break the bleeder screw loose at the caliper that is dragging and the problem goes away you know hydraulic circuit for that wheel is sticking. If you crack the bleeder loose and the wheel is still tight then you know something in the caliper itself is binding such as a piston in the caliper bore.