Mitsubishi Eclipse 1990-1998 Repair Guide

Wheel Speed Sensors

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See Figures 1

Each wheel is equipped with a magnetic sensor mounted a fixed distance from a toothed ring which rotates with the wheel. The sensors are replaceable but not interchangeable; each must be fitted to its correct location. The toothed rings are replaceable although disassembly of the hub or axle shaft is required.

The wheel speed sensor is designed to produce a voltage directly proportional to the speed of the wheel. In other words as the speed of the wheel increases, so does the voltage. The voltage should not fluctuate when the wheel speed (speedometer) reading is steady.

TESTING



1991-94 Vehicles

See Figure 1

  1. Raise and safely support the vehicle.
  2.  
  3. Detach the suspected malfunctioning sensor wire connector.
  4.  



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Fig. Fig. 1: Measure the resistance between the speed sensor terminals

  1. Connect an ohmmeter to the sensor connector 2 terminals.
  2.  
  3. The resistances should be 0.8-1.2 kilo-ohms for 1991-94 vehicles, or 1.0-1.2 kilo-ohms for 1995-98 vehicles.
  4.  
  5. If the resistance is not within specifications, replace the speed sensor.
  6.  

REMOVAL & INSTALLATION



See Figures 2, 3, 4, 5, 6, 7, 8 and 9

  1. Elevate and safely support the vehicle.
  2.  
  3. Remove the wheel and tire assembly and the disc brake rotor.
  4.  
  5. Remove the inner fender or splash shield.
  6.  
  7. Beginning at the sensor end, carefully disconnect or release each clip and retainer along the sensor wire. Take careful note of the exact position of each clip; they must be reinstalled in the identical position. Rear wheel sensor harnesses will be held by plastic wire ties; these may be cut away but must be replaced at reassembly.
  8.  



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Fig. Fig. 2: Front speed sensor and mounting bolt-1991-94 vehicles



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Fig. Fig. 3: Rear speed sensor and mounting bolt-1991-94 vehicles

  1. Detach the sensor connector at the end of the harness.
  2.  
  3. Remove the two bolts holding the speed sensor bracket to the knuckle and remove the assembly from the vehicle.
  4.  

The speed sensor has a pole piece projecting from it. This exposed tip must be protected from impact or scratches. Do not allow the pole piece to contact the toothed wheel during removal or installation.



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Fig. Fig. 4: Inspect removed speed sensor for damaged pole piece. Also check pole piece for foreign material or metal adhesion

  1. Remove the sensor from the bracket.
  2.  



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Fig. Fig. 5: Exploded view of the wheel speed sensors and ABS rotor-1995-98 FWD vehicles



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Fig. Fig. 6: Wheel speed sensors and ABS rotor locations-1995-98 AWD vehicles

To install:
  1. Assemble the sensor onto the bracket. Note that the brackets are different for the left and right front wheels, as well as both side rear wheels. Each bracket has identifying letters stamped on it.
  2.  



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Fig. Fig. 7: Left and right speed sensor brackets with identification markings-1991-94 vehicles



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Fig. Fig. 8: Checking the clearance between the pole piece of the speed sensor and the rotor's toothed surface-1991-94 vehicles

  1. Identify the front speed sensor brackets as follows:
    1. FR:Indicates that the bracket is for the front speed sensor.
    2.  
    3. R:Indicates that the bracket is for the right wheel.
    4.  
    5. L:Indicates that the bracket is for the left wheel.
    6.  

  2.  
  3. Identify the rear speed sensor brackets as follows:
    1. R:Indicates that the bracket is for the right wheel.
    2.  
    3. L:Indicates that the bracket is for the left wheel.
    4.  

  4.  



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Fig. Fig. 9: Rear speed sensor bracket identification marking

  1. Temporarily install the speed sensor to the spindle or knuckle; tighten the bolts only finger tight.
  2.  

During speed sensor installation to the mounting bracket, make sure the letters FR are visible. Be careful when installing the speed sensor on the vehicle, that the pole piece at the tip of the sensor does not strike the toothed edge of the rotor, and damage them.

  1. Route the cable correctly and loosely install the clips and retainers. All clips must be in their original position and the sensor cable must not be twisted. Improper installation may cause cable damage and system failure.
  2.  
  3. Use a brass or other non-magnetic feeler gauge to check the air gap between the tip of the pole piece and the toothed wheel. The correct gap is 0.012-0.035 inch (0.3-0.9mm). Tighten the 2 sensor bracket bolts to 10 ft. lbs. (14 Nm) with the sensor located so that the gap is the same at several points on the toothed wheel. If the gap is incorrect, it is likely that the toothed wheel is worn or improperly installed.
  4.  
  5. Tighten the screws and bolts for the cable retaining clips.
  6.  
  7. Install the disc brake rotor, inner fender or splash shield.
  8.  
  9. Install the wheel and tire assembly. Lower the vehicle to the ground.
  10.  
  11. Inspect the brake system for proper operation.
  12.  

 
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