42
Figure 3-22 MAP (intake pressure sensor)
3.2.12
Road Speed
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:
Summary of Contents for ATO1000 Series
Page 1: ......
Page 2: ...Version Info Version Date Remarks V1 0 2020 06 ...
Page 52: ...Chapter 3 Automotive Test 49 Figure 3 30 Electronic fuel pump test ...
Page 71: ...68 Figure 3 49 K line test ...
Page 79: ...76 Figure 3 57 Mazda 6 Cylinder internal pressure measurement ...
