Acura Coupes and Sedans 1994-2000 Repair Information

Wheel Speed Sensor

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Each wheel has its own wheel speed sensor which sends a small AC signal to the control module. Correct ABS operation depends on accurate wheel speed signals. The vehicle's wheels and tires must all be the same size and type in order to generate accurate signals. If there is a variation between wheel and tire sizes, inaccurate wheel speed signals will be produced.


WARNING
It is very critical that the wheel speed sensor(s) be installed correctly to ensure continued system operation. The sensor cables must be installed, routed and clipped properly. Failure to install the sensor(s) properly could result in contact with moving parts or over extension of sensor cables. This will cause ABS component failure and an open circuit.

Acura uses a contactless type of sensor that detects the rotating speed of the wheel. It is constructed of a permanent magnet and a coil. Attached to the rotating parts are gear pulsers (aka. Tone Rings). When these pulsers turn, the magnetic flux around the coil in the wheel sensor alternates its current. This generates voltages in a frequency or wave pattern. These wave pulses are sent to the ABS control unit which identifies the speed of each of the four wheels.

See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Wheel speed sensor pulses

REMOVAL & INSTALLATION



See Figure 2

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Fig. Fig. 2: Typical front and rear wheel speed sensor mounting


CAUTION
Vehicles equipped with air bag systems (SRS) have components and wiring in the same area as the front speed sensor wiring harnesses. The air bag system connectors are yellow. Do not use electrical test equipment on these circuits. Do not damage the SRS wiring while working on other wiring or components. Failure to observe correct procedures may cause the air bag system to inflate unexpectedly or render the system totally inoperative.

  1. Raise and safely support the vehicle as necessary for access.
  2.  
  3. Make certain the ignition switch is OFF .
  4.  
  5. Detach the sensor harness connector.
  6.  
  7. Beginning at the connector end, remove grommets, clips or retainers as necessary to free the harness. Take careful note of the placement and routing of the harness; it must be reinstalled in the exact original position.
  8.  
  9. Remove the bolt holding the speed sensor to its mounting; remove the sensor. If it is stuck in place, gently tap on the side of the mounting flange with a hammer and small punch; do not tap on the sensor.
  10.  

To install:
  1. Place the sensor in position; install the retaining bolts loosely. Route the harness correctly. Avoid twisting or crimping the harness; use the white line on the wires as a guide.
  2.  
  3. Once the harness and sensor are correctly but loosely placed, tighten the sensor mounting bolts. Tighten bolts to 16 ft. lbs. (22 Nm).
  4.  
  5. Working from the sensor end to the connector, install each clip, retainer, bracket or grommet holding the sensor harness. The harness must not be twisted. Tighten any bolt holding brackets to 7 ft. lbs. (10 Nm).
  6.  
  7. Attach the wiring connector.
  8.  
  9. Use the ABS checker to check for proper signal from the wheel speed sensor.
  10.  
  11. Carefully lower the vehicle to the ground.
  12.  

INSPECTION



See Figure 3

Click image to see an enlarged view

Fig. Fig. 3: You must check the gap between the pulser and wheel speed sensor

  1. Use a non-metallic feeler gauge to measure the gap between the sensor and the pulser.
  2.  
  3. Rotate the hub or axle slowly by hand, taking measurements at several locations.
  4.  
  5. Specifications are as follows:

    Integra front and rear0.0160.039 inches (0.41.0mm)
     
    Legend front0.0240.047 in. (0.61.2mm)
     
    Legend rear0.0120.051 in. (0.31.3mm)
     
    Vigor front0.0240.035 in. (0.60.9mm)
     
    Vigor rear0.0200.035 in. (0.50.9mm)
     

  6.  

 
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