On most 2WD and 4WD vehicles, the front wheel speed sensors are permanently mounted to the brake rotor splash shield, which must be replaced as an assembly should the sensor fail. On 2WD vehicles, the rotor must be removed for access.
The front wheel speed sensors operate with the help of sensor tone wheels. The tone wheels are metal rings equipped with teeth on their outer diameter. The AC voltage is produced as the teeth come within and leave alignment with the sensor. The tone wheels are attached to the rotor on 2WD vehicles and to the front hub and bearing assembly on 4WD vehicles.
A properly operating speed sensor should have a resistance value of 900-2000 ohms.
REMOVAL & INSTALLATION
See Figure 1
- Raise and support the front of the vehicle safely on jackstands.
- Remove the tire and wheel assembly.
- Remove the brake caliper from the mounting bracket and support using a coat hanger or wire. Make sure the brake line is not stretched, kinked or otherwise damaged. The line should NEVER support the weight of the caliper.
- For 2WD models, remove the hub and rotor assembly. Refer to the brake disc procedure in this section.
- For 4WD vehicles, remove the brake disc. Refer to the procedure in this section, then remove the hub and bearing assembly.
- Disengage the sensor wiring connector.
- Disconnect the sensor wire from the clip(s) on the control arm.
- Remove the splash shield retaining bolts, then remove the shield and sensor assembly.
- Mount the sensor and splash shield assembly to the steering knuckle. Install the retaining bolts and tighten them to 11-19 ft. lbs. (15-26 Nm).
- Connect the wiring to the clip(s) on the control arm. Check the wiring for correct routing. If removed, install and tighten the clip retaining bolt/nuts. The wiring on some vehicles/components may be marked at the appropriate clip mounting position; so look for a paint stripe on the sensor wire.
- Engage the wiring connector.
- On 4WD models, install the hub and bearing assembly.
- Install the brake disc.
- Remove the support, then reposition and secure the brake caliper.
- Install the tire and wheel assembly. Adjust the wheel bearings on 2WD models.
- Remove the jackstands and carefully lower the vehicle.