Ram 1500, 2500, 3500, 2WD and 4WD, 2001-2005

Wheel Speed Sensors

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Diagnosis & Testing



Air Gap
  1. Raise and safely support the vehicle securely on jackstands.
  2.  
  3. Remove the sensor from the differential.
  4.  
  5. Measure and record the distance from the underside of the sensor flange to the end of the sensor pole piece. This distance represents dimension B. This dimension should be 1.07-1.08 in. (27.18-27.43mm). If dimension is not within specification, replace the speed sensor.
  6.  
  7. Measure and record the distance between the sensor mounting surface of the differential case and the teeth at the top of the exciter ring. This distance represents dimension A. This dimension should be 1.085-1.120 in. (27.56-28.45mm). If dimension is not within specification, replace the exciter ring.

    Click image to see an enlarged view

    Fig.

  8.  
  9. Subtract dimension B from dimension A to determine sensor air gap. The gap should be 0.005-0.050 in. (0.127-1.27mm). Measure and record the distance (A) between the sensor mounting surface of the differential case and the teeth at the top of the exciter ring

    Click image to see an enlarged view

    Fig.

  10.  

  1. Raise and safely support the vehicle securely on jackstands.
  2.  
  3. Remove the sensor from the differential.
  4.  
  5. Measure and record the distance from the underside of the sensor flange to the end of the sensor pole piece. This distance represents dimension B. This dimension should be 1.07-1.08 in. (27.18-27.43mm). If dimension is not within specification, replace the speed sensor.
  6.  
  7. Measure and record the distance between the sensor mounting surface of the differential case and the teeth at the top of the exciter ring. This distance represents dimension A. This dimension should be 1.085-1.120 in. (27.56-28.45mm). If dimension is not within specification, replace the exciter ring.

    Click image to see an enlarged view

    Fig.

  8.  
  9. Subtract dimension B from dimension A to determine sensor air gap. The gap should be 0.005-0.050 in. (0.127-1.27mm). Measure and record the distance (A) between the sensor mounting surface of the differential case and the teeth at the top of the exciter ring

    Click image to see an enlarged view

    Fig.

  10.  

Resistance Test
  1. Raise and safely support the vehicle securely on jackstands.
  2.  
  3. Ensure the ignition key is in the OFF position.
  4.  
  5. Disconnect the speed sensor electrical harness.
  6.  
  7. Measure resistance between the terminals on the speed sensor
  8.  
  9. Resistance should be 1000-2500 ohms.
  10.  
  11. If resistance is not within specification, check the harness for continuity.
  12.  
  13. If continuity exists, the sensor is faulty.
  14.  

  1. Raise and safely support the vehicle securely on jackstands.
  2.  
  3. Ensure the ignition key is in the OFF position.
  4.  
  5. Disconnect the speed sensor electrical harness.
  6.  
  7. Measure resistance between the terminals on the speed sensor
  8.  
  9. Resistance should be 1000-2500 ohms.
  10.  
  11. If resistance is not within specification, check the harness for continuity.
  12.  
  13. If continuity exists, the sensor is faulty.
  14.  

Removal & Installation



  1. Raise the vehicle.
  2.  
  3. Remove the brake line mounting nut, if fitted, and remove the brake line from the sensor stud.
  4.  
  5. Remove the mounting stud from the sensor and shield.
  6.  
  7. Remove the sensor and shield from the differential housing.
  8.  
  9. Disconnect the wire and remove the sensor.
  10.  

To install:

  1. Connect harness to sensor. Be sure the seal is securely in place between the sensor and wiring connector.
  2.  
  3. Install O-ring on sensor if removed.
  4.  
  5. Install sensor on differential; housing, sensor shield, mounting stud. Tighten to 18 ft. lbs. (24 Nm).
  6.  
  7. Install the brake line on the sensor stud and install the nut.
    NOTE
    Use the original or replacement sensor bolt only. The bolt is special and must not be substituted.

  8.  
  9. Lower the vehicle.
  10.  

  1. Raise and support vehicle.
  2.  
  3. Disconnect speed sensor from the main harness.
  4.  
  5. Remove sensor mounting bolt from the steering knuckle.
  6.  
  7. Remove the sensor from the steering knuckle.
  8.  

To install:


WARNING
A special bolt is used to attach the sensor. Use only a factory replacement bolt.

  1. Install the sensor into the steering knuckle.
  2.  
  3. Install mounting bolt and tighten to 11 ft. lbs. (15 Nm).
  4.  
  5. Connect sensor wire to main harness and ensure wire is routed away from hot or moving components.
  6.  
  7. Remove supports and lower vehicle.
  8.  

  1. Raise and support vehicle.
  2.  
  3. Disconnect wire from rear sensor on axle housing.
  4.  
  5. Remove sensor and bracket mounting bolt and remove sensor and bracket.
  6.  

To install:

  1. Secure sensor wire to rear brake hose with clips provided.
  2.  
  3. Install sensor and mounting bracket in axle housing. Install mounting bolt and tighten to 18 ft. lbs. (24 Nm).
  4.  
  5. Connect wire to sensor and secure wire to mounting bracket.
  6.  
  7. Remove support and lower vehicle.
  8.  

2-Wheel Drive
  1. Raise and support the vehicle.
  2.  
  3. Remove the sensor bolt from the steering knuckle/hub and remove the sensor.
  4.  
  5. Disconnect the ABS wheel speed sensor wire and detach the wire from securing clips.
  6.  

To install:

  1. Tighten the sensor bolt to 17 ft. lbs. (23 Nm).
    NOTE
    Use the original or replacement sensor bolt only. The bolt is special and must not be substituted.

  2.  
  3. The remainder of the procedure is the reverse of removal.
  4.  

 
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