The passive wheel speed sensor has been around a long time. It works quite differently than the active speed sensors that are found on most cars today. The passive speed sensor creates its own AC signal that changes frequency with wheel speed. This signal is only present while the wheel is turning at a rate fast enough to create the AC signal.
On the hubs for 2005-2014 Subaru Legacy and Outback applications, a speed sensor mounts into the knuckle. It’s exposed end extends out behind the bearing to capture pulses from an encoder ring on the back of the bearing.
Replacing wheel bearings on both sides of a vehicle used to be standard procedure as it was economical insurance against a comeback. In those days, a set of bearings and races could be purchased under $5 a side, including the seal. A technician worth his salt could install and adjust a set of bearings in
Vehicles: All ABS-equipped vehicles Condition: Vehicle had wheel bearing hub replaced on one side. Repair Procedure: If you diagnose a bad hub bearing on one side of a vehicle and the ABS wheel speed sensor or tone ring is integral to the bearing, you may need additional repairs to restore proper ABS functioning. In many