A Simple and Speedy Guide to ABS Speed Sensor Installation
Your vehicle's anti-lock braking system (ABS) is a safety setup that prevents uncontrolled skidding. It does this by releasing the brakes to keep your wheels from locking up. It can also increase braking pressure on a wheel that is spinning a lot faster than the others. All of this happens very quickly-applying and releasing pressure as much as 15 times per second. The result is greatly improved vehicle control, especially on slippery surfaces. In order to do this, the ABS relies on the speed sensors on each wheel. The system won't work if even one sensor malfunctions. Installing a new one should take less than an hour.
Required skill level: Intermediate
Needed tools and materials
- Floor jack
- Jack stands
- Wrench and socket set
- New ABS speed sensor
- Lug wrench (if necessary)
Setting things up
Before starting, make sure your vehicle is parked on level ground and that your engine has cooled over a number of hours. Disconnect the negative battery cable from the terminal. Use the floor jack to lift the side of your vehicle with the malfunctioning sensor. Make sure your vehicle is securely supported by the jack stands before getting under it.
Removing the old sensor
Start by unplugging the old ABS speed sensor's wiring harness connector by pulling the tangs away from the connector and pulling the plug off the connector. Use the appropriate socket or wrench to loosen and remove the sensor.
Installing the new one
Take your new ABS speed sensor and install it in the same way as the old part was. Be sure to firmly tighten the retaining bolt. Plug in the wiring harness connector so that it snaps into place. Use your floor jack to raise your vehicle a little, remove the jack stands, then lower your vehicle to the ground. Reconnect the negative battery cable to the terminal.
Tips and warnings
- In some cases, the speed sensor may be part of the hub assembly. You may need to use the lug wrench to remove the wheel in order to access it.
- If your vehicle uses drum brakes, you will need to remove the drum to access the sensor.
FAQs: ABS Speed Sensor
- The anti-lock brake system or ABS speed sensor monitors the rotational speed of the wheels. It sends the signals to the controller, which will activate the anti-lock braking feature. It is also known as the wheel speed sensor or brake sensor.
- In newer configurations, the ABS sensors are installed in the wheel hub assembly. On the other hand,ABS sensors in older systems are situated outside the wheel hub.
- The anti-lock braking system allows quicker stops when the vehicle is running at higher speeds. It also prevents skidding when making sudden stops, especially on wet roads or conditions where the wheels may lose traction.
- The ring, magnet, and other components of the ABS wheel speed sensor may be exposed to road debris and other harsh elements on the road. This can cause the sensor to eventually fail. The pressure and strain put on the sensor over the years may also lead to wear and tear.
- Symptoms of a bad ABS speed sensor include a flashing ABS light, pumping in the brake pedal, loss of traction (especially on poor surface conditions), and longer stopping distance.
- Even with a flashing ABS light, you can still drive and get to your destination safely. However, you will have to be more careful when making quick stops or driving on roads with poor surface conditions.
- The price of an ABS wheel speed sensor ranges from $17 to $500, depending on the year, make, and model of your vehicle. It also varies based on the quantity sold, which can be per piece or as a set.
When your vehicle is running at higher speeds, you have to pump the brakes several times to keep the wheels from getting jammed. Otherwise, you may lose control of your car. The anti-lock brake system (ABS) does this automatically, allowing the brakes to be pumped about 15 times per second. It enhances the vehicle’s ability to stop using sensors that work like a tachometer.
How does an ABS speed sensor work?
The ABS speed sensor, also known as the wheel speed sensor or brake sensor, has two vital parts: the ring and the magnet. When the ring makes contact with the magnet, this produces a voltage, which turns into a signal transmitted to the ABS control system. This is how the controller keeps track of the rotational speed of each wheel.
There are instances when the wheels may not rotate at the same speed or no longer be in sync due to loss of traction. Good thing the sensor can tell the difference and send accurate information to the ABS controller, which can then figure out if the wheels are indeed locking up.
In case of a slippage between the wheels, the anti-lock brake system will also be alerted. It will then take over the manual braking of your vehicle for your safety.
Where can you find the ABS sensor?
In newer configurations, the ABS sensors are installed in the wheel hub assembly. In older systems, however, the sensors are situated outside the wheel hub, either in the steering knuckle or the differential housing. These sensors may be mated with a ring gear, which may be set on the brake rotor or drum. It depends on the type of braking system employed by the vehicle. The system may use one or as many as four ABS sensors for its anti-lock braking feature or may have a different approach when it comes to the overall design.
How important is the wheel speed sensor?
The anti-lock braking system allows quicker stops when the vehicle is running at high speeds. It prevents skidding when making sudden stops, especially on wet roads or conditions where the wheels may lose traction. Essentially, this helps avert vehicular accidents and other untoward driving situations.
By keeping tabs on the rotational speed of each wheel, the ABS wheel speed sensor allows the ABS controller to keep the braking power in check.
For instance, when there is loss of traction and the wheels lock up, the sensor will send signals to convey this message to the controller or the on-board computer. The system will then reduce the braking force of the wheels, enabling them to turn efficiently and maintain their grip on the road.
In most modern vehicles, the ABS sensors are used not only to achieve the ideal traction but also to support the stability control feature.
What are the causes of ABS failure?
The ring, magnet, and other components of the ABS sensor may be exposed to debris and other harsh elements on the road, such as mud, salt, and corrosive agents. This can cause the sensor to eventually fail.
The pressure put on the sensor over the years may also lead to wear and tear, causing the sensors to malfunction or break completely.
ABS sensors should be checked and cleaned regularly to ensure that they stay in good condition. Doing so will allow them to record the information accurately and transmit signals without interruption.
In some cases, the failure of the sensor may be blamed on the wiring or connectors that have gone bad. A faulty module can also cause the problem. So be sure to inspect these parts before replacing the sensor itself.
What are the symptoms of a bad ABS speed sensor?
Even without inspecting the ABS sensor, there are ways to tell if they are still working well or starting to fail. If you encounter any of these troubles or spot any of these signs, it is best to have your brake system checked at once.
Flashing ABS light
When the on-board computer of your vehicle detects any kind of flaw with the sensor, it switches on the ABS light on your dashboard. You may use a scanner to read the codes or have a mechanic perform a checkup.
Vehicle stopping longer than usual
With a faulty sensor, the anti-lock braking system may not be engaged right away. It may not respond well to conditions that require optimum traction control. As a result, the vehicle may skid, have trouble making quicker stops, or suffer from considerable loss of tire surface grip, especially on wet or icy roads.
Pumping in the brake pedal
The pumping in the brake pedal can be the result of the faulty signal from the sensor. The faulty signal that is transmitted to the brake control may indicate slippage even when this is not the case.
Is it still safe to drive your vehicle if the ABS light is on?
A flashing ABS light does not necessarily mean that the brakes of the vehicle are no longer working. You can still drive to your destination safely, but you will have to be more careful when making quick stops and driving on roads with poor surface conditions. You have to keep your vehicle’s limitations in mind. Without a fully functional sensor or with a broken wire or component in the system, the anti-lock braking feature may be disabled or may not work completely. This may result in the wheels locking up and the vehicle skidding.
If the ABS light flashes along with the brake warning light, then it is best not to drive your vehicle at all —at least until a full brake system check is done. The brake light comes on for a number of reasons, such as low brake fluid, brake pad wear, or lack of fluid pressure. These can make the brakes unreliable.
How much is a new ABS wheel speed sensor?
An ABS wheel speed sensor cost ranges from around $17 to $500. The price varies largely based on the year, make, and model of your vehicle plus whether or not you are buying the sensor per piece, in a set of two or four, or as a kit.
ABS Speed Sensor - Quick Guide for Buyers
The job of the anti-lock braking system (ABS) speed sensor is to monitor wheel rotation. As it evaluates the speed, it helps figure out whether the ABS should be engaged to take over manual braking under certain conditions, such as when there’s loss of traction. When the sensor fails, the ABS may be triggered all of a sudden or may not engage at all. The brakes stop responding the way they used to. In a snap of a finger, things can get weird and out of control. Before things go out of hand, the speed sensor must be checked. If it’s already defective or damaged, then this must be replaced at once. When shopping for a new speed sensor for the vehicle’s anti-lock braking system, there are a couple of things to keep in mind.
Look for ABS speed sensors that are engineered to match the exact OE specs. These sensor replacements should be compatible with the make, model, and year of the vehicle. You won’t have trouble hooking them up to the anti-lock braking system. You can be sure that they won’t only be installed quite easily but will also be sending the right signals. OE sensors won’t require any modification and can be used right after they’re installed properly. When looking for a stock replacement ABS speed sensor, take note of the OE number to make sure that you have the right component.
Take note of the specs. See if the sensor comes with a harness or wire harness extension or if it’s designed as a pin or blade type. Some speed sensors come with a 2-prong connector or a couple of wires. Some may even have a wheel mounting location. All these details matter and must be taken into consideration. You may consult your vehicle manual to find the exact replacement you’re looking for.
Don’t just order any ABS speed sensor without first checking its application, whether it’s for the front or rear or the driver or passenger side. Take note of the sensor location, whether it’s mounted on the rear axle or at the rear center.
Testing an ABS Speed Sensor - Quick, Easy Guide for DIYers
When the anti-lock braking system of your vehicle suddenly kicks in or won’t engage, this can be blamed on a faulty speed sensor. The sensor may not be giving accurate signals for the wheel rotation and speed, causing some confusion and brake problems in the process. To figure out what’s wrong with the ABS speed sensor and to confirm if it’s the one causing the trouble, you have to test the it and check for corrosion or contaminants that prevent it from sending the right signals.
Difficulty level: Easy to Moderate
Tools and materials you'll need:
- Jack and jack stands
- Wheel blocks
- 1/4-inch ratchet
- 8- to 10-mm socket
- Voltage meter
- Brake cleaner
Step 1: Jack up the rear of the vehicle and support the raised portion with jack stands. The wheel blocks must be placed around the front tires. Remove the rear tires when testing the ABS speed sensor.
Step 2: Trace the point where the electrical wiring harness from the engine meets the wiring harness of the sensor. Use a vehicle manual to locate this part.
Step 3: Use a 1/4-inch ratchet with an 8- to 10-mm. socket for moving the sensor from its original position.
Step 4: Inspect the sensor’s end. See if there’s something that resembles a fur ball at the end. If so, then the ABS speed sensor is probably restricted or obstructed because of contamination. To fix this, all you need is a brake cleaner. After you spray the cleaner on the sensor, remove the contaminants by wiping them off with a rag.
Step 5: Unplug the engine harness from the sensor harness. After disconnecting them, change the settings of the voltage meter to ohms. The voltage meter’s positive and negative terminals must be connected to the sensor’s input and output. If you see an infinity mark in the meter, this confirms that the sensor is indeed malfunctioning. The defective sensor must be replaced. If it doesn’t register an infinity when set to ohms, you have to alter the settings of the meter back to volts. If the reading on the meter is over 5 volts, the sensor is about to fail. If the reading is below 5 volts, the knock sensor must be checked to see if it’s corroded. You have to trace electrical connections all the way to the sensor to see if there’s any corrosion.
Step 6: Reinstall the rear tires once the ABS speed sensor has been checked and tested. Bring the vehicle back to the ground. Remove the stands and wheel chocks.