Wheel Speed Sensor Air Gap Detection (FA left)
- Check the relevant wheel speed sensor and its fixing. In case the distance between pole-wheel and sensor (air gap) is too wide, push the wheel speed sensor back to the pole wheel to adjust the air gap - Check wheel speed sensor for correct voltage output (sufficient voltage output?) - Replace the ABS-ECU, if sensor and air gap are correct Remark: A repair can be considered successful only when the vehicle is driven again in order to detect possible dynamic failure.
What you'll see
No driver-visible symptom recorded.
System reaction
ABS function at relevant wheel is switched off ABS function at other wheels is still available ATC engine and brake control is switched off HSA is deactivated EBL is not deactivated Drag Torque Control is not deactivated
Diagnostic depth
An airgap failure on the left side of the front axle was detected. The air gap is too large, the wheel speed sensor amplitude voltage is below a defined trigger threshold.
- distance between pole-wheel and sensor (air gap) too wide - wheel speed sensor voltage output too low - ABS-ECU defect