The ABS wheel speed sensors on the W204 monitors road wheel movement and sends an electronic signal to the ABS module. This signal is used to calculate road wheel speed to help with ABS braking and stability control features. This article show a guide on how to replace ABS sensor for Mercedes Benz W204.
When an ABS wheel speed sensor fails, the ABS module loses road wheel speed for the corresponding wheel and sets a fault code for the ABS wheel speed signal. When a fault code is set, the ABS warning light will illuminate. You will have to scan the module and read the fault codes to determine which speed sensor is the problem. Keep in mind, other problems can illuminate the ABS warning light.
Note:Be sure to scan and read fault codes before you start replacing expensive parts. Begin by safely raising and supporting the vehicle and removing the wheels on the sensors you are changing.
Parts Required: ABS wheel speed sensors (Amazon)
Hot Tip: Check for fault codes before replacing
Performance Gain: Repair faulty ABS sensor
Complementary Modification: New brake pads
Time: 2 hours
Tab: $40 to $200
Talent: 2 Tools: 10mm wrench, E12 wrench, floor jacks, jack stands, wheelchocks, safety glasses, torque wrench
Applies to: C350 (2007-14), C180 (2007-14), C200 (2007-14), C230 (2007-14), C250 (2007-14), C280 (2007-14), C300 (2007-14), C320 (2007-14)
Benz W204 ABS Sensor Replacement Guide:
Front ABS Sensor Replacement:
You will need to loosen front fender well liner (red arrow) enough so you can remove the rear liner (yellow arrow).Please see our article on fender liner removal for additional assistance:Mercedes Benz W204 Wheel Well Liner Removal Guide
With the liner off you can access where the front ABS sensor is routed to the pass through connection as well as access it’s mounting points (yellow arrow).
Disconnect the sensor form the pass through connection by pressing down on the wire (red arrow) and pulling the sensor out.
Disconnect the cable from the holder on the brake lines (yellow arrow) and where it connects to the inner fender (red arrow).
Remove the cable fro the holder on the spindle (red arrow).Then use a 10mm wrench,and remove the single bolt holding the sensor in place (yellow arrow).
All of the bake and suspension hardware is considered single use and comes microencapsulated from the factory.Make sure to replace the hardware when performing this job.
With the bolt removed,pull the sensor out from the steering knuckle (red arrow).
Installation of the new cable is the reverse of removal.
Front ABS Sensor Replacement:
To replace the rear sensor you will need to remove the rear render well liner (red arrow).Please see our article on fender liner removal for further assistance:Mercedes Benz W204 Wheel Well Liner Removal Guide
The rear ABS sensor is similar to the front in that it runs from the wheel hub to the pass through connection in the fender well (red arrow).
Disconnect the sensor from the pass through connection by pressing down on the wire (red arrow) and pulling the sensor out.
Remove the cable from the plastic holder in the wheel well.
Use an E12 wrench and remove the plastic mount that holds the cable and sensor in place (red arrow).
All of the brake and suspension hardware is considered single use and comes microencapsulated from the factory.Make sure to replace hardware when performing this job.
With the bolt and mount removed you can pull the sensor out from the wheel carrier.Installation is the reverse of removal.