On Vehicle Testing ABS system

We used a little Mazda Demio for out test of ABS system on car. Here fer fotos of ABS system components on Mazda Demio.












Wheel speed sensors. We identified that sensors are inductive pick up and captured pattern on the right front wheel. Inductive pick up wheel speed sensor will generate its own AC voltage and will increase its amplitude and frequency with faster speeds and its an analog signal not digital.
Measuring the air gap for wheel speed sensors. Front right 0.711 mm and front left 0.55 mm. The air gap is very important for inductive wheel speed sensors and can affect the output signal by generating not enough voltage as ECU looks at particular voltage and can interrupt proper working of ABS system.







Analog signal pattern. We also recorded a Frequency of this sensor with multimeter and it was 72.39 Hz. This frequency shown how fast signal changes from positive voltage to negative voltage. Showing that wheel speed sensor working but doesn't show how good is it working.















Using a scan tool we can see life data of ABS sensors and solenoids. As we rotate front right and rear right wheel we can see change in speeds of both wheels when car on a hoist. Also we can see if ABS motor on or off and various ABS valves. Also we used Honda Accord Euro R 2000, the one Adams drives, as we can go to actuators test and test ABS solenoids. During the test brake pedal was vibrating as when ABS working. So with test we can find which solenoids are seized or not working properly.

And this test we done on Nissan Cefiro 1997, we actuate solenoids driving around 30 km/h on a grass and braking hard as an emergency stop. This proofs that ABS system works even at low vehicle speeds. On a picture we can see ABS motor is on and Solenoids (in) are on as well. So ABS is a safety system for late model vehicles providing driver with steereability and stability in emergency braking situations.