ESP_a021 — WSS General V Diff Fault
Full alert identifier: ESP_a021_WSSGeneralVDiffFault
Alert description
Wheel Speed Sensor: General Fault.
Potential impact
Will disable VDC/TC and degrade ABS
Set condition
If the difference between maximum and minimum wheel speed related to a reference speed exceeds 5%. A generic wheel speed sensor fault is set if no wheel specific fault could be determined. During system mode ABS and backup-EBD (Electr. Brake Force Distribution) and below 20 kilometers per hour the deviation is 6 kilometers per hour for velocities < 100 kilometers per hour and 6% for a velocity > 100 kilometers per hour.
Clear condition
1.) Open circuit in the WSS line 2.) Short circuit to + voltage in the WSS line 3.) Short circuit to GND in WSS line 4.) WSS dislodging from bracket 5.) Input amplifier in ECU faulty 6.) tooth wheel missing 7.) WSS not installed 8.) too great airgap 9.) incorrect tooth count
Check other alerts
With Service Mode Plus enabled, open Service Alerts → All. Review the other alerts for clues to the cause of ESP_a021.