Do you want to know the wheel speed sensor location in your vehicle? If so, you are on the right page.
The wheel speed sensor(WSS) of the anti-lock braking system (ABS) acts in different capacities, which makes it an important part of a vehicle. When an ABS’s wheel speed sensor starts failing, many symptoms may begin to show, and to replace it, you will need to know the wheel speed sensor location.
Read on to find out the wheel speed sensor location of your car, how to check if it’s bad, how to replace it, and lots more.
Wheel Speed Sensor Location
Wheel speed sensors are commonly called ABS sensors. They’re mounted on the axles of all ABS-equipped vehicles, and you can find them on the wheel hubs of your vehicle close to the brake rotors. The rear wheel speed sensor is located on the wheel cylinder or rear axle housing.
If the anti-lock braking system has four-speed sensors, one is usually attached to each tire behind the brake rotor. When an ABS has three sensors, two are usually attached to each front tire, while the other one can be found in the rear axle and not the rear tire.
The type of Anti-lock braking system is a major determinant of the number of sensors a vehicle will have. There are four anti-lock braking system configurations, and they are:
Two-Channel, Four-Sensor ABS: There is a sensor attached to each tire; however, there is a channel for the front sensors and another one for the sensors at the back. When a wheel locks up, and the speed sensors detect such, the ABS is engaged in that area of the car.
Three-Channel, Three-Sensor ABS: Here, a sensor is attached to each front tire, and one is attached to the rear axle. Although the rear tires are monitored concurrently, there is a separate evaluation for the front tires.
Three-Channel, Four-Sensor ABS: With a sensor attached to every tire, the rear tires, however, work with one controller.
Four-sensor ABS: There is a sensor attached to each tire with separate evaluations. This type of configuration is very common with recently produced vehicles.
Related: How to Tell Which ABS Sensor Is Bad (Expert Guide)
Symptoms of a Failing Wheel Speed Sensor
Some indications that can show if the wheel speed sensor has gone bad include:
1. ABS Warning Light Comes On
Most of the recently manufactured vehicles are made with an anti-lock braking system, electronic stability system, and traction control to facilitate a more secure use of brakes in whatever driving condition a driver finds himself. The ABS sensor is a major data source for all of these systems.
When the speed sensor starts failing, one of the ABS indicators, traction control indicator or check engine indicator will come up on the vehicle’s dashboard.
2. Anti-lock Braking System Stop Working
The anti-lock braking system’s controller of a vehicle is aided by the sensors in determining whether tires are getting locked up as a result of hard braking.
Data is no longer sent to the ABS control module if a speed sensor starts failing. Consequently, the anti-lock brake is shut down by the ABS control module in the absence of a speed sensor.
3. Pulsating Brake Pedal
The duty of an anti-lock braking system’s speed sensor is to measure the speed of the tire it is attached to. The ABS controller receives wrong data when the sensors are bad.
This false information could create a false feeling that the car is starting to slide off, which will make the ABS controller activate its anti-lock brakes.
In this situation, brake pressure is released by the ABS, which pumps the brakes quickly. Due to this, the brake lever pulsates when it is pressed.
4. Traction Control And Stability Control Stop Working
When a speed sensor fails, it shuts off the traction control of the vehicle, its stability control, or other features which may assist the driver. In certain circumstances, a bad cable could be the reason why data is not sent from the speed sensor to the ABS controller.
If this happens, maintaining traction when the weather condition is bad will not be an easy task; likewise, there may be reoccurring braking problems.
If any of these features made to assist the driver start to have issues, the speed sensor of the ABS should be examined at a mechanic garage.
5. The Speedometer Doesn’t Work
This sign is not regular and occurs mostly in old vehicle models. If it is noticed that the speedometer is not working, a bad speed sensor could be responsible for this.
Having a speedometer that does not work is a safety risk as it creates uncertainty as to how fast or slow a driver is driving, which could endanger the lives of the road users as well as the driver.
Also Read: Transmission Speed Sensor Location
What Is the Wheel Speed Sensor, and How Does It Work?
An ABS brake sensor is another name for the ABS wheel speed sensor or may simply be referred to as an ABS sensor. Whatever the name is preferred, it remains an essential component of the Anti-lock braking system (ABS).
A lot of modern vehicles are equipped with the Anti-lock Braking System. An ABS sensor is attached to the axle or a tire to read the speed at which a tire rotates. Many ABS sensors have a magnet and a toothed ring joined with a coil. An electric field is created when the ring contacts the magnet, which turns to the signal being transmitted to the anti-lock braking system controller.
After the signal has been received, the controller sums up the speed at which each tire is moving or that of the axle. This processed information goes to the Engine Control Module (ECM).
The ABS activates when the engine control module detects a tire is starting to lock up. It swings into action very quickly that it makes a grinding sound and feels like the vehicle is pulsating.
The ABS brake sensor assists in regulating the movement of a vehicle in an emergency situation if such a vehicle has traction control. When there is no traction, the tires of the vehicle move at a different speed, which will make the ABS swing into action.
The force applied to the tires is reduced by the ABS, which causes a problem. When force reduces, the wheels gain their grip and spin normally in no time. It is this same ABS sensor that makes stability control systems in recent vehicles work as well.
How to Replace a Wheel Speed Sensor
A simple guide on the procedure to be followed in replacing an ABS sensor without having to engage a professional is given below:
Lug nut sockets and a half-inch torque wrench should be used to loosen the nuts tightened to the wheel before jacking up the vehicle.
Thereafter, lift up the vehicle using the jack and use stands to hold it down in one position. Ensure the vehicle has been jacked up from the correct part. Also, make sure that the stands have been well-positioned before the vehicle is brought down on the stands.
What should be done next is to take out the speed sensor from the tire. Removing the brake rotors and pads may be necessary so as to clearly see the bolts attaching the sensors to the hub.
After doing this, take out the clips holding the sensor wires to the body of the vehicle. Unplug these wires to make it possible to completely remove them. Then, apply an emery cloth or sandpaper on rusty surfaces that will accommodate the new sensors.
Get new brake parts and speed sensors. Go through the third step in reverse. Attach the new connector, then ensure it is well tightened to the body of the vehicle. Put speed sensors in the knuckle or the hub.
If it is necessary to take out the brakes, too, then just install the caliper bracket and brake rotors with the brake pads. Ensure everything rotates in accordance with factory requirements.
With a new speed sensor in place, the next thing to do is to reattach the tires, and this can be done by merely fixing the tires back to the hubs and holding them down with the lug nuts before tightening.
Then, put the jack in the right position beneath the car, lift up the vehicle and take out the stands. After this, the vehicle can be lowered back to the ground.
It is advisable to put the vehicle in reverse, which will make the tires take a backward spin. The majority of vehicle models require a force of about 36 kgs – 45 kgs. However, a force of about 41 kgs – 54 kgs is required for trucks and SUVs. Follow the earlier procedure and use a half-inch drive breaker bar to tighten the nuts to requirements.
Take the vehicle out for test driving. Do not forget that the lights on the dashboard are not supposed to remain on after replacing speed sensors. So in a situation where they do not go off, ensure that the vehicle is taken to a professional mechanic to properly reset its internal computer. To run the test drive, apply a safe route, then accelerate and step hard on the brakes and ascertain that the ABS works just fine.
Wheel Speed Sensor Replacement Cost
Replacing an average speed sensor comes at the cost of about $200 to $400 for each sensor, although this depends on labor cost and the vehicle model. An estimate of around $100 – $150 is expected to be the cost for each sensor, and an extra $100 – $300 will go for labor fees.
Speed sensors for luxury cars do not come cheap and usually cost more, and working on some vehicle models is usually more difficult, which will add up to the cost of labor.
Nonetheless, replacing the ABS sensor without going to a mechanic is not so difficult, especially when the necessary tools are available. With basic mechanical know-how, this is one problem a driver could solve in his personal garage. Though sensors may get stuck after some time, a good heat source will make removing them much easier.
Also Read: Service Brake Assist (Meaning, Causes & Fixes)
Frequently Asked Questions – Wheel Speed Sensor Location
What happens if the wheel speed sensor fails?
When a speed sensor fails, it shuts off the vehicle’s traction control, stability control, or other features that may assist the driver. In certain circumstances, a bad cable could be the reason why data is not sent from the speed sensor to the ABS controller.
How many wheel speed sensors are on a car?
More recent vehicles have as many as four-speed sensors with one sensor attached to each wheel (two-speed sensors to the front and rare wheels, respectively.)
How much does it cost to replace the wheel speed sensor?
Replacing a single sensor may cost around $200 to $400, considering the fact that there’s one sensor per wheel. Basically, after an average distance of 30,000 – 50,000 miles, sensors ought to be replaced.
Can I drive with a bad wheel speed sensor?
Generally, if the speed sensor of a vehicle breaks, driving such a vehicle is not advisable. Suppose a speed sensor wears out or gets damaged. In that case, it may not show on the vehicle immediately, and a lot of difference may not show in the vehicle’s performance even if the ABS indicator is on, except when driving on a slippery road.
Is the ABS sensor the same as the wheel speed sensor?
Yes, the ABS sensor is also known as the ABS brake sensor or the wheel speed sensor. Since each tire does not rotate at one particular speed, the sensors transmit the speed at which all four tires rotate to the ECM, and then the ECM decides if the tires are starting to lock up.
Can wheel speed sensor affect brakes?
If working properly, the ABS is activated once the brakes are heavily pressed to slow down the vehicle quickly without getting the brakes locked up and making the vehicle tumble. The data the ABS speed sensor collects is used in regulating brake pressure to stop the brakes from locking up and prevent traction loss when the brakes are pressed heavily.
Conclusion – Wheel Speed Sensor Location
As stated earlier, some speed sensors are located in the tire region just behind the brake rotors. However, some vehicles have theirs on the axle, and they transmit data on the speed at which each tire rotates to the ABS controller, which then processes it before passing the same to the Engine control module.
When things go wrong with the sensor, it could put lives at risk because drivers are unsure of the speed at which they are driving because wrong data is transmitted. However, this problem is not irreparable and can be fixed either by the driver himself or by engaging a qualified mechanic to help in fixing the problem, which comes at a higher cost due to labor fees.