Wheel Speed Sensor: Service and Repair

ABS system components for rear axle (all-wheel drive), removing and installing
1. ABS speed sensor
- Checked by On Board Diagnostic (OBD)
- Before inserting sensor, clean mounting hole inner surface and coat with lubricating paste G 000 650
2. Hex socket head bolt, 8 Nm (71 in. lb)
3. Trailing arm
4. plash plate
5. Hex bolt, 10 Nm (7.37 in. lb)
6. Brake disc





7. Phillips-head screw
8. Wheel hub with rotor
- Press out and in
9. Circlip
10. Wheel bearing
- Replace each time after removing
- Pressing out and in

Speed sensor on rear axle (disc brakes all- wheel drive), removing and installing

Removing

- Raise vehicle.





- Open connector -1- cover -2-.



- Separate speed sensor and speed sensor wiring connector -1-.
- Remove bolt -1-from trailing arm.
- Remove ABS speed sensor out of trailing arm.







- Before inserting speed sensor, clean hole inner surface and coat speed sensor all-round with solid lubricant paste G 000 650.






- Insert speed sensor into hole in trailing arm and tighten bolt -1- to 8 Nm (71 in. lb).





- Connect speed sensor to speed sensor wiring and close connector -1- cover -2-.


Rotor on rear axle (all-wheel drive), checking or removing and installing

- Raise vehicle.
- Remove wheel.





- Remove bolt -1- from trailing arm.
- Pull ABS speed sensor out of trailing arm.
- Check rotor is not damaged or dirty.
- If rotor is damaged, remove wheel hub with rotor and replace.


Removing and installing rear speed sensor wiring (all-wheel drive)


Special tools and equipment

- VAS 1978 Wiring harness repair set

Removing

- Obtain radio code on vehicles with coded radio.
- Disconnect battery.
- Separate speed sensor wiring speed sensor connection.
- Raise vehicle.





- Open connector -1- cover -2-
- Separate speed sensor and speed sensor wiring connector -1-.


- Remove rear side panel trim.





- Separate speed sensor wiring -arrow- with wire strippers from VAS 1978 and remove faulty wiring.
- Strip 15 mm (5/8 in.) of insulation from end of wire with wire strippers and bend half of stripped wire back.





- Guide in new speed sensor wiring.





- Connect speed sensor to speed sensor wiring -1- and close connector cover -2-.
- Clip in speed sensor wiring -arrows-.
Make sure the wiring is not twisted when installing the speed sensor wiring in the wheel housing.

- Cut 2-pin connector off new speed sensor wiring with wire stripper pliers.
- Strip 15 mm (5/8 in.) of insulation from end of wire with wire strippers and bend back half.
- Connect speed sensor wiring with help of suitable crimp connector from wiring harness repair set VAS 1978.