ATOx004 manual - Page 95

The speed sensor is generally installed on the drive output shaft of the speedometer of the gearbox or near the back

of the head of the speedometer, to provide information for the ECM and monitor power. Usually is Hall type, there

are 3 wires: power, signal, and ground, output square wave signal (some models will be analog, 2 wires, output

inductive signal, sine wave). Use a BNC to banana cable, connect one end to channel 1 of the oscilloscope, the

other end of the black plug is grounded, and the red connector is connected to the signal line of the vehicle speed

sensor with a needle. Lift the vehicle as a whole or lift the driving wheels or connect the signal to a road test, start

the vehicle, put in gear to rotate the wheels, and observe the waveform. The frequency of the square wave increases

with the increase of vehicle speed.

Use ATO oscilloscope to test the vehicle speed sensor, the specific operation is shown in Figure 3-23: