Installation Time for ABS Wheel Speed Sensor Replacement – 1 Hour
A simple ABS wheel speed sensor replacement may help remove the “DBC malfunction! Drive carefully” message from your BMW iDrive display and the yellow BRAKE and ABS lights on your dashboard.
Ok…i’ll admit it. There are times that I have come seriously close to taking a ball peen hammer to the iDrive display in my 2011 335i. As our cars become older and get some mileage on their wheels, it is an uncomfortable truth that the error messages will start appearing more frequently on our BMWs dashboards and displays. Heat, mileage, dirt and corrosion, water, and just normal wear and tear take their toll on the sensors that monitor our vehicle components. And as our BMWs become more advanced with state of the art driving assistance systems, more complex sensors are needed.
The ABS wheel speed sensor on a BMW plays a key role in your vehicles Anti-Lock Braking System (ABS) as well as Dynamic Braking Control (DBC). The sensors, located on all four hubs behind the brake rotors, measure the speed of each wheel and relay that information back to the control module that controls your BMWs ABS system. If the ABS system identifies an issue, it can automatically apply brake pressure as needed to help the driver from losing control of their vehicle. ABS wheel speed sensor replacement plays a critical role in driver safety as well as fuel consumption, vehicle emissions, and driver comfort.
A BMW that requires an ABS wheel speed sensor replacement may prompt a “DBC malfunction! Drive carefully” error message on the iDrive display. It will also activate several dashboard lights, including the yellow BRAKE, ABS, and SERVICE ENGINE SOON messages. It also can trigger several different error codes on your BMW diagnostic scanner. Common causes for wheel sensor failure are internal short circuits, excessive buildup of road dirt and grime, cuts or abrasions in the wiring, or damage/corrosion at connection plug.
Tools and Supplies
1/2″ Impact wrench with 17mm deep impact socket (or alternative method to remove wheel lug nuts)
1/2″ Torque Wrench
3/8″ 5mm Hex Socket
3/8″ metric socket wrench kit
Metric nut drivers (optional, but helpful)
3/8″ socket wrench extender
Rear wheel ABS speed sensor replacement
- Jack up and support with jack stands the wheel that you are replacing the sensor on. Not sure how to jack and support your BMW? Read our article on the simple and safest way by clicking here.
- Remove lug nuts with impact wrench and 17mm deep impact socket (or other alternative method).
- Locate the ABS wheel speed sensor on back side of wheel hub as shown in following image:
- Using a 3/8″ 5mm hex socket and extension, remove bolt attaching the speed sensor to the wheel hub. Grasp the sensor and pull out. If sensor is stuck in the wheel hub, use a small flat blade screwdriver to gently lever the sensor out.
- The connection for the rear wheel ABS speed sensor is behind the fender liner. The fender liner can be easily loosened in 2 steps:
- Remove the four 8mm screws (3 screws on the edge of the fender and 1 on the bottom)
- Remove the 10mm plastic nut located in the middle of the fender liner:
- Pull the fender liner back until the ABS speed sensor electrical connection is accessible.
- Disconnect the ABS speed sensor connector. Make sure to document how the sensor wire is routed through your vehicle’s suspension prior to removing it (photos are a good idea). Remove the old sensor wire from the vehicle.
- Install new sensor and route wire through suspension and back to car. I found it very helpful to use zip ties to anchor the new wire to suspension…the nasty little plastic clips that originally held it are very difficult to secure after being opened. ***Make sure to route the new sensor wire over suspension parts as shown in following image…if not you run the risk of damage to the wire.
- Reinstall fender liner, wheel, and lower car back down to ground.
- Using your 1/2″ torque wrench, torque wheel lug nuts to 120 Nm (90 Ft-Lb).
Front wheel ABS speed sensor replacement
The front wheel ABS speed sensor replacement is much easier than the rear replacement. Follow the same exact steps as above with the following exceptions:
- You do not need to remove the fender liner to access the speed sensor electrical connector. They are located in plain view behind the front wheel strut.
- The speed sensor is located on the back of the wheel hub, not the side.
When you start your car and drive it after the repair, the iDrive display message, BRAKE and ABS lights will disappear. You most likely will need to use your diagnostic scanner to erase all of your error codes to remove the SERVICE ENGINE SOON light on your dashboard. Look at it this way…the money you just saved doing this repair yourself would have bought two scanners!
If you have any questions or comments, please feel free to comment on this article or contact us. And congratulations for Doing It Yourself!
The Repair Difficulty Level displays graphically how challenging the repair is, from easy to advanced. Easy repairs usually require very few tools, have short repair times and do not require jacking and supporting the vehicle. As the difficulty level rises, expect the repair to demand more time, specialized tools, and better understanding of mechanics to complete the job.