Vehicle speed output

ABS/TCS HU/CM terminal: V(+) - AC(-)
Oscilloscope setting:
1 V/DIV (Y), 5 ms/DIV (X), DC range
Vehicle condition: Driving 30 km/h (18.6 mph)
NOTE:
- As vehicle speed increases, the wave period shortens.
Fig 1: Inspecting Wheel Speed Output Using An Oscilloscope
Courtesy of MAZDA MOTORS CORP.