Wheel Speed Sensor: Testing and Inspection

Carefully inspect the toothed sensor ring (tone wheel) at the suspected faulty wheel speed sensor for missing, chipped or broken teeth; this can cause erratic speed sensor signals. Tone wheels should show no evidence of contact with the wheel speed sensors. If contact was made, determine cause and correct before replacing the wheel speed sensor. Excessive runout of the tone wheel can cause erratic wheel speed sensor signals. Tonewheel runout should not exceed 0.15 mm (0.006 inch). Replace rear hub/bearing assembly if tone wheel runout exceeds the specification. Inspect tone wheels for looseness on their mounting surfaces. Tone wheels are pressed onto their mounting surfaces and should not rotate independently from the mounting surface. Check the wheel speed sensor head alignment to the tone wheel. Also check the gap between the speed sensor head and the tone wheel to ensure it is at specification between a minimum of 0.40 mm (0.016 inch), not to exceed a maximum of 1.2 mm (0.047 inch).