Front Wheel Speed Sensor: Inspection

Set the probe of oscilloscope to TCM harness connector.
Connector & terminal

(B54) No. 20 (+) - No. 14 (-):

Fig 1: Setting Probe Of Oscilloscope To TCM Harness Connector
Courtesy of SUBARU OF AMERICA, INC.
Lift up the vehicle and raise the vehicle speed up to 20 km/h (12 MPH).
Check the waveform of front wheel speed sensor when vehicle speed is at 20 km/h (12 MPH).
NOTE: The waveform cycle changes as the speed changes.

Fig 2: Front Wheel Speed Sensor Waveform
Courtesy of SUBARU OF AMERICA, INC.