5 FAQs On Wheel Speed Sensor
Here are answers to some common wheel speed sensor questions:
1. What Is A Wheel Speed Sensor?
A wheel speed sensor (also known as an ABS sensor or ABS brake sensor) is a critical part of your braking system. The speed sensor works with the tone wheel to monitor the speed of your vehicle’s wheels and relay the data to the ABS.
The ABS control module reads this data to ensure that all the wheels move at the same speed. Accordingly, it corrects any wheel and brings it to speed. With the help of wheel speed sensors, your car’s ABS can also prevent your wheels from locking up during hard braking.
Additionally, the speed sensors assist the traction control system to gain more control over your vehicle when you’re hitting uneven roads.
However, like any other braking part, the wheel speed sensors are subject to wear and tear. They can get damaged by dust, dirt, etc., and may often need replacement.
2. Where Is The Wheel Speed Sensor Located?
A speed sensor is usually located on the steering knuckle behind the wheel’s brake rotor. Sometimes it may also be installed directly on the wheel axle.
While most modern vehicles have four sensors (one on each wheel), an ABS system can also have other configurations:
- Two-channel four sensor ABS: An ABS brake sensor is located on each wheel, but the vehicle has one channel for the front sensors and one for the rear.
- Three-channel three sensor ABS: One sensor is located at each front wheel, and a rear wheel speed sensor is installed on the rear axle. The rear wheels are monitored together by the rear sensor, while the front wheels are monitored separately.
- Three-channel four sensor ABS: One sensor is installed on each wheel, but a single controller monitors the rear wheels.
3. How Long Does It Take To Replace A Wheel Speed Sensor?
Diagnosing sensor failure is pretty straightforward, and replacing it with a new sensor shouldn’t take more than an hour (including the diagnostic time).
4. How Do I Replace A Wheel Speed Sensor?
Whether you own a Honda, Chevrolet, or Toyota, replacing a speed sensor as a DIY isn’t difficult. However, you need the right tools and should know your car parts.
Sometimes, you may need to remove certain brake parts like the brake caliper, brake pad, and brake rotor to access the speed sensor.
If you’re unsure, it’s best to have a professional at your dealership replace the ABS wheel speed sensor for you or get a mobile mechanic to drop by and help you out.
But, if you still plan to do it yourself, here’s how:
- Engage the parking brake and disconnect the negative battery cable.
- Raise your vehicle using jack stands.
- Use a breaker bar and lug nut socket set to remove the wheel from the wheel hub assembly.
- Disconnect the electrical connector from the ABS sensor harness.
- Remove the retaining bolt holding the sensor onto the steering knuckle. Also, remove any fasteners holding the sensor wiring harness in place.
- Remove the sensor from the vehicle.
- Ensure that the new sensor has the same design as the old sensor. Preferably, go for an OEM sensor.
- Install the sensor, and fasten the retaining bolt. Also, reinstall the wheel speed sensor harness.
- Using a torque wrench, tighten the fasteners and other parts as per the specifications given in the repair manual.
- Reconnect the ABS sensor electrical connector.
- Reinstall the brake rotor and brake caliper along with your brake pad if you had removed them earlier.
- Reinstall the wheel on the wheel hub, and remove the jack stands to lower your vehicle.
- Reconnect the negative battery cable.
- Finally, use a scan tool or code reader to clear any ABS codes or other Diagnostic Trouble Codes (DTCs).
5. Why Is My New Sensor Not Working?
If your wheel’s new sensor isn’t working, there could be some issue with the wheel bearing.
The sensor will only function when it’s at an exact air gap to the tone ring in the wheel bearing. Any misalignment or debris can affect this air gap, causing the new sensor to not work.