Service function guideWheel Speed Sensor Diagnosis

This guide covers the complete diagnostic process for wheel speed sensors and tone rings using live ABS (Anti-lock Braking System) data, from understanding the system's operation to performing a road test and verifying repairs. It is written for working mechanics and experienced DIYers who already have a scan tool capable of reading ABS live data and want a structured, repeatable method. You will learn how to prepare the vehicle, capture and interpret live wheel speed PIDs (Parameter IDs), test sensors and tone rings with a multimeter and oscilloscope, and diagnose intermittent faults that set no trouble code. After finishing, you will be able to confidently isolate a faulty sensor, damaged tone ring, wiring issue, or bearing encoder and confirm the fix with data rather than guesswork.