Audi Cars 1999-05

Wheel Speed Sensors

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The impulse (speed sensors) are located at each wheel and provide the speed reference to the control unit. The sensors are permanently magnetized inductive sensors that read pulses from a tooth wheel on each hub. A voltage signal is generated as each tooth passes through the magnetic field. The sensors are replaceable.

Removal & Installation



Front
  1. Make sure the ignition switch is in the OFF position.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the front wheels.
  6.  
  7. Remove the boot from the inner wheel housing and disconnect the electrical connector.
  8.  
  9. Carefully pull the sensor out of the wheel bearing housing (knuckle).
  10.  
  11. Installation is in reverse order of removal noting the following:
  12.  
  13. Clean the mounting hole in the bearing housing and apply a light coating of a lubricating paste, such as Part No. G 000 650.
  14.  
  15. Using a new clamping sleeve, apply a light coating of a proper lubricating paste and install the sleeve into the housing, then install the sensor.
  16.  



Click image to see an enlarged view

Fig. The front ABS impulse sensor is pressed into the bearing holder (knuckle) and retained by a tensioning sleeve

Rear
  1. Make sure the ignition switch is in the OFF position.
  2.  
  3. Raise and safely support the vehicle.
  4.  
  5. Remove the rear wheels.
  6.  
  7. Detach the electrical connector and remove the wire harness from the retaining guides.
  8.  
  9. Carefully pull the sensor out of the wheel bearing housing (knuckle).
  10.  
  11. Installation is in reverse order of removal noting the following:
  12.  
  13. Clean the mounting hole in the bearing housing and apply a light coating of a lubricating paste such as Part No. G 000 650.
  14.  
  15. Using a new clamping sleeve, apply a light coating of a proper lubricating paste and install the sleeve into the housing, then install the sensor.
  16.  



Click image to see an enlarged view

Fig. The rear ABS impulse sensor is pressed into the rear hub on Front Wheel Drive vehicles, and into the bearing holder (knuckle) on All Wheel Drive vehicles, and retained by a tensioning sleeve

 
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