Front Speed Sensor

Speed Sensor Connector:

Speed Sensor Bolt:

Sensor Rotor:

Speed Sensor Oscilloscope Waveform:

1. Inspect wheel speed sensor.
a. Disconnect the speed sensor connector in the engine compartment.
b. Measure the resistance between terminals, refer to SPECIFICATIONS. If sensor resistance is not as specified, replace sensor.
c. Check for no continuity between each terminal and sensor body.
d. Connect speed sensor connector.
2. Check that the sensor installation bolt is tightened properly. The bolt should be torqued to 9 ft.-lb.
3. Inspect the serrations on the rotor assembly.
a. Remove the two bolts and remove the brake caliper and mounting plate.
b. Remove the rotor disk.
c. Inspect the sensor rotor serrations for scratches, cracks, warping or missing teeth.
d. Install the rotor disk and brake cylinder assembly with the original two bolts. Torque to 69 ft.lb..
NOTE: Do not strike the hub, it and the serrations are very fragile.
4. Check the sensor rotor for runout. Measure the sensor rotor runout at 0.08 in. (2 mm) from the serration edge. Maximum sensor rotor runout (fluctuation measured at the top of 3 consecutive serrations) : 0.004 in. (0.1 mm). If not as specified, replace the front axle hub.
5. Inspect front speed sensor and sensor serrations by using an oscilloscope.
a. Connect an oscilloscope to the speed sensor connector.
b. Run the vehicle at 12.4 mph, and inspect speed sensor output wave.
c. Check that C is 0.5V or more. If not as specified, replace the speed sensor.
d. Check that B is 70% or more of A. If not as specified, replace the front axle hub.