Tone Wheel: Description
WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
The tone wheel is used in conjunction with the wheel speed sensors. (Refer to BRAKES - ABS/ELECTRICAL/FRONT WHEEL SPEED SENSOR - DESCRIPTION) or (Refer to BRAKES - ABS/ELECTRICAL/REAR WHEEL SPEED SENSOR - DESCRIPTION)