S42.30-0004-01
The gap between the speed sensor and the rotor is tested during this actuation function using a measuring curve diagram.
The wobble that is caused by too much wheel play, broken teeth and soiling of the rotor is graphically displayed in the HHT display.
Perform test on a suitable level surface.
Test procedure:
1. Slowly accelerate vehicle to faster than 10 kph
2. Press start button
3. Allow vehicle to roll
- measuring is started automatically by the HHT at less than 10 kph. See bar in HHT display.
- end of test is indicated by bar in HHT display. Bar is completely black.
If the speed does not drop below 10 kph after 90 seconds, the HHT automatically stops the test.
4. After the continue button has been pressed, each individual measuring curve can now be called up and analyzed by pressing the relevant button as follows:
FR = Front right wheel
FL = Front left wheel
RR = Rear right wheel
RL = Rear left wheel
The measuring curve that has been called up is highlighted by flashing.
S42.30-0005-01
Good display
All four measuring curves are the same and show a speed (v) that reduces evenly with time (t).
S42.30-0006-01
Faulty display
One or more faulty measuring curves clearly deviate from the good measuring curves and are very irregular or lie outside the range of the display.
Example:
Faulty rear left speed sensor measuring curve