0xD9120A Wheel Speed Sensor Wheel 3-Abnormal Rate Of Change
Action: Check the cables and connectors between EPM and wheel-speed sensor for short-circuits and open-circuits. Measure resistance of Sensor and cabling. Resistance must be between 800 x85. 2000 Ohm. Measure insulation resistance of sensor and cabling to vehicle GND. Resistance must be > 200kOhm. Do waveform check with oscilloscope. Check and correct air gap between wheel speed sensor and tone wheel by measuring the wheel speed signal. (Wheel speed sensor signal must be higher than 100mV peak to peak at wheel speed of about 3-5km/h). Check wheel speed sensor mounting (Check 'KlxE4mhylsa'). Check the tone wheel for dirt and metallic particles, for wobble, for pitch error, for the correct number of teeth.
What you'll see
Symptom:
System reaction
SystemReaction: ABS restricted. ESP control off. ATC off. DTC off. Diff-lock maybe restricted. HSA off. Trailer Brake off. Wheel Brake Monitoring off. ABS Warning Lamp.
Diagnostic depth
Detection: Plausibility test for the wheel speed sensor signal frequency (freq jumps) or rate of the ABS active/inactive status change is too high.
Cause: Large airgap, dirty tone wheel, missing or destroyed tone wheel teeth, toggling tone wheel, production-failures of tone wheel, damaged wheel speed sensor, wheel speed sensor mounting