If the anti-lock brakes on your vehicle fail, you will notice the dashboard light comes on or your brakes may lock. The ABS sensor measures the wheel speed of each wheel and sends the data to the module. When it senses a brake lock, it relieves pressure, then pumps the brake for you at a rapid speed. It is easy to replace the sensor yourself by following these tips.
Prepare to Replace the ABS Sensor
To replace the ABS sensor, gather:
- work gloves
- rags
- sandpaper or emery cloths
- jacks stands and wheel chocks
- socket and ratchet set with extensions
- assorted pliers and screwdrivers
- tire wrench
- torque wrench and torx socket set
- scan tool
- brake cleaner
- silicone lubricant
- oil lubricant
Use the tire wrench to loosen the lug nuts on the tires by rotating then one-quarter turn to the left, but leave them in place. Raise the vehicle on jacks stands referring to your manual for suggested jack points, then slide wheel chocks under the opposite wheels. Completely remove the tires and set them aside.
While optional, a scan tool will help you determine which sensor has failed. You will commonly need to test each sensor on older vehicles.
Remove the Old Wheel Sensor
Disconnect the negative battery cable clamp, which commonly has a minus sign. Locate the wheel sensor on the suspension or axle, consulting your manual, if needed.
Remove the screws or bolts on the sensor using the correct socket and racket , screwdriver, or wrench. If you have trouble removing bolts, spray them with lubricating oil. Disconnect the wire harness, noting how wires connect, or label them. Pull the sensor free using a wrench, checking the stator ring for damage.
Sometimes, the sensors may just be dirty. Clean the sensor with a damp rag, but avoid using chemical cleaners. Reinstall the sensor, and test the repair.
Install the New Sensor
Use the old sensor as a guide to buy a replacement. Wipe the mounting hole with brake cleaner and a rag, using the emery cloth or sandpaper to remove rough spots.
Rub some silicone lubricant on the O-ring (rubber piece) to keep it from breaking, or apply a lubricant compatible with rubber. Attach the sensor and the wires aligning the mount holes, being aware of pushing pins into the contacts. You should hear a click if the sensor installs correctly.
Tighten the bolts using the correct torque suggested in your manual. Reattach the scan tool to clear the code, reinstall the tires, battery cable, and lower the vehicle. Drive at 35 MPH to test the repair.
If you prefer to have a professional repair the sensor for you or give your car an inspection, consult a mechanic at your local auto repair shop.