FYI:

The operation of an ABS sensor is not unlike that of a crank angle sensor, using a small pick-up that is affected by the movement of a phonic wheel, moving in close proximity. The relationship between the phonic wheel and the sensor result in the production of a continuous Alternating Current (AC) 'sine wave' that can be monitored on an oscilloscope. The sensor, recognisable by its two electrical connections (some may have a coaxial braided outer shield) will produce an output that can be monitored and measured on the oscilloscope.