Check Abs Wheel Speed Sensor Unit

Visually check the tip of the front ABS wheel speed sensor for foreign particles or damage. If necessary, clean the tip or replace the front ABS wheel speed sensor.
Disconnect the front ABS wheel speed sensor connector.
Check the front ABS wheel speed sensor cable for discontinuity. If defective, replace the front ABS wheel speed sensor.
Connect a 12 V power supply to No. 1 terminal of front ABS wheel speed sensor connector, then attach resistance to the No. 2 terminal. Rotate the wheel at about 3 km/h (2 MPH), and measure the voltage using an oscilloscope.
Standard value of output voltage:

0.7 - 1.4 V

Courtesy of SUBARU OF AMERICA, INC.
- Vehicle stopped state
Standard value of output voltage:

0.7 - 1.4 V

Courtesy of SUBARU OF AMERICA, INC.
- Driving condition
Standard value of output voltage:

0.7 - 2.8 V
- Driving condition
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- Driving condition (enlarged view)
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Replace the following parts if it is found defective.
- If the output voltage is out of the standard value: Replace the magnetic encoder (front hub unit bearing).
- If the output voltage is within the standard value: Replace the VDC control module and H/U.