Jeep Wagoneer/Commando/Cherokee 1984-1998

Speed Sensors

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TESTING



See Figure 1

  1. Check the wheel speed sensor air gap using a brass feeler gauge. If the air gap measures out of specifications, adjust to the correct specifications.
  2.  
  3. Disengage the speed sensor wiring harness connector. Inspect the condition of the connector and repair if necessary.
  4.  
  5. Using an ohmmeter, measure the resistance between the wheel speed sensor connector terminals.
  6.  
  7. The resistance should measure between 5000-8000 ohms. If the resistance measures outside this value, replace the wheel speed sensor.
  8.  



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Fig. Fig. 1: Checking wheel speed sensor resistance

Removal & Installation



Front

See Figures 2, 3 and 4



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Fig. Fig. 2: Common wheel sensor with spacer strip

  1. Elevate and safely support the vehicle. Turn the front wheel outward for easier access to the sensor.
  2.  
  3. Before disassembly, note sensor wire routing including location of all clips and retainers. The sensor wire must be routed correctly during reassembly to avoid damage from moving parts.
  4.  
  5. Carefully remove the wire ties holding the sensor wire to the brake lines and the steering knuckle.
  6.  
  7. If the sensor is coated with mud, slush, etc., clean the sensor and surrounding area. This will prevent damage to the sensor and tone wheel during removal.
  8.  
  9. Remove the sensor attaching screw and remove the sensor from the steering knuckle.
  10.  
  11. Loosen the grommet holding the sensor wire from the wheel arch panel.
  12.  
  13. In the engine compartment, disconnect the sensor wire connector from the ABS harness. Carefully remove the sensor and harness from the car.
  14.  

To install:
  1. The wheel sensors have a plastic spacing strip attached to the contact face. Inspect this spacer and note the condition. If the strip is securely attached and in good condition, no adjustment will be needed after installation. If the strip is damaged or not present, an air gap adjustment will be required.
  2.  



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Fig. Fig. 3: Front sensor wire routing

  1. Feed the sensor wire through the grommet hole in the wheelwell panel. Connect the sensor connector to the ABS harness and seat the rubber grommet in the panel.
  2.  
  3. Position the sensor on the steering knuckle and install the attaching bolt finger-tight.
  4.  
  5. If the spacer strip was intact and in good condition, lightly press the sensor against the tone wheel. Hold the sensor in this position and tighten the retaining bolt to 11 ft. lbs (14 Nm).
  6.  
  7. If the spacer was missing or damaged, clean the contacts on the sensor with a clean shop towel. Remove the spacer strip completely if loose or torn. After the sensor is loosely held in position by the retaining bolt, use a brass feeler gauge to set the air gap from the sensor to the tone wheel. Correct air gap is 0.013-0.019 in. (0.33-0.48mm). Tighten the retaining bolt to 11 ft. lbs. (14 Nm) and recheck the air gap with the feeler gauge.
  8.  

Use of a brass or non-magnetic gauge is required. Do not use common steel feelers; the small magnets within the sensor may be damaged. Correct air gap is critical to the proper operation of the sensor.

  1. Use new wire ties to secure the sensor wire to the brake lines and steering knuckle.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: Adjusting the sensor-to-tone wheel air gap

Rear

See Figures 5 and 6

  1. Raise and fold forward the rear seat to gain access to the rear sensor connectors.
  2.  
  3. Disengage the sensor connector from the ABS harness; push the sensor grommet and wiring through the floor pan.
  4.  
  5. Elevate and safely support the vehicle.
  6.  
  7. Remove the wheel and brake drum.
  8.  
  9. Carefully remove the wire ties holding the sensor wires to the brake lines and rear axle.
  10.  
  11. Loosen or unseat the backing plate grommet holding the sensor wire.
  12.  
  13. Remove the bolt holding the sensor to the bracket. Remove the sensor by pulling the wire through the grommet hole in the backing plate.
  14.  

To install:
  1. The wheel sensors have a plastic spacing strip attached to the contact face. Inspect this spacer and note the condition. If the strip is securely attached and in good condition, no adjustment will be needed after installation. If the strip is damaged or not present, an air gap adjustment will be required.
  2.  



Click image to see an enlarged view

Fig. Fig. 5: View of the rear wheel speed sensor and tone wheel

  1. Feed the sensor wire through the grommet hole in the backing plate and seat the grommet in the plate.
  2.  
  3. If the spacer strip was intact and in good condition, lightly press the sensor against the tone wheel. Hold the sensor in this position and tighten the retaining bolt to 11 ft. lbs (14 Nm).
  4.  
  5. If the spacer was missing or damaged, clean the contacts on the sensor with a clean shop towel. Remove the spacer strip completely if loose or torn. After the sensor is loosely held in position by the retaining bolt, use a brass feeler gauge to set the air gap from the sensor to the tone wheel. Correct air gap is 0.030-0.036 in. (0.76-0.91mm). Tighten the retaining bolt to 11 ft. lbs. (14 Nm) and recheck the air gap with the feeler gauge.
  6.  

Use of a brass or non-magnetic gauge is required. Do not use common steel feelers; the small magnets within the sensor may be damaged. Correct air gap is critical to the proper operation of the sensor.

  1. Route the sensor wire to the rear seat area and feed through the access hole. Seat the sensor wire grommets in the floorpan.
  2.  
  3. Use new wire ties to secure the sensor wiring to the brake lines and rear axle. Make certain that the wiring is clear of all moving and/or hot components.
  4.  
  5. Install the brake drum and wheel. Lower the vehicle to the ground.
  6.  
  7. Within the car, connect the sensor to the ABS harness. Reposition the seat and carpet.
  8.  



Click image to see an enlarged view

Fig. Fig. 6: Installing the rear wheel speed sensor

 
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