4 Signs of a Failed ABS Wheel Speed Sensor
The ABS wheel speed sensor has several functions and is a critical component to your car. When it starts to fail, you may notice several symptoms. In this article, we will discuss the symptoms, location, function, and replacement cost of a failed ABS wheel speed sensor. Let’s take a quick look at the signs you can expect.
Symptoms of a Failed ABS Wheel Speed Sensor
The most common symptoms of a failing ABS sensor are the ABS warning light on the dashboard, a pulsating brake pedal, and a loss of anti-lock braking or traction control. Your dashboard may also show other warning lights, such as the check engine light or traction control light.
As you can see, there isn’t really much to tell if your ABS sensor is faulty. This is mainly because the ABS control module turns on the ABS warning light and prevents accidents by disabling the system.
Here is a detailed list of signs of a faulty or defective ABS wheel speed sensor:
1. Flashing warning lights
Your dashboard has several important lights to warn you of danger. If your ABS wheel speed sensor fails, the ABS light may be one of the first signs that you notice all the symptoms of a bad ABS wheel speed sensor.
At first, you may simply see the ABS warning light come on. However, if other systems start to malfunction, the traction and stability control warning light may also come on. In rare cases, a defective ABS wheel speed sensor may cause the speedometer to display no value.
2. Brake pedal pulsates when braking
ABS sensors measure the speed of each wheel. If one of the ABS sensors is faulty, one or more wheels will show an incorrect speed. This will make the ABS control module think the car is skidding on a slippery surface.
This will activate the ABS and traction control. You will notice this by the feeling of the brake pedal pulsating or pumping when braking.
3. Anti-lock braking system failure
If the ABS wheel sensors fail, the anti-lock braking system will not function. If a fault is detected, the system will sound an alarm and the ABS warning light will come on.
From this point on, the vehicle’s electronic control module will no longer receive valuable data from the sensors. The computer uses this information to determine if the wheels are locked and assistance is needed. Since the system has no idea what is going on, the ABS will be switched off until a repair is completed.
4. Loss of traction or stability control
You may lose not only the anti-lock braking system, but also other features such as stability control, traction control, rollover stability, and hill start assist. The computer also shuts down these systems when the sensors stop sending information.
However, problems can occur even if the ABS light doesn’t come on. If you can’t maintain traction in bad weather or when braking hard, your ABS wheel speed sensors may be the problem. A damaged cable connection from the sensor to the ECM may also be the cause.
ABS Wheel Speed Sensor Locations
ABS wheel speed sensors are located on the wheels behind the brake discs, but some are mounted directly on the axles. Each vehicle has a different number of ABS wheel speed sensors.
If your system contains four ABS wheel speed sensors, there is one on each wheel behind the disc. A system with three sensors has one sensor on each front wheel and one on the rear axle instead of one on the rear wheels.
The type of ABS determines how many sensors your vehicle has. Here are the four ABS configurations: Dual Channel ABS with 4 sensors: There’s one sensor on each wheel, but one channel on the front and one on the rear. If the speed sensors detect that a wheel is locked, the ABS will intervene in that part of the vehicle.
Three Channel ABS with 3 sensors: One sensor on each front wheel and one sensor on the rear axle. The rear wheels are monitored simultaneously and the front wheels are evaluated individually. 3-Channel ABS with 4 Sensors: Each wheel has a sensor attached, the rear wheels are actuated through a controller.
4-Sensor ABS: Each wheel has a sensor monitored individually. This is the most common configuration in modern vehicles.
What does an ABS Wheel Speed Sensor do? The ABS wheel speed sensor is sometimes called the ABS brake sensor, or just the ABS sensor. Whatever you call it, it’s an important part of ABS. Anti-lock braking systems (ABS) are found on most new cars.
ABS wheel sensors are attached to the wheels or axles and calculate how fast the wheels are rotating. Most ABS sensors contain a magnet surrounded by a gear ring and coil. Contact between the magnet and the ring creates an electric field that is converted into a signal that is sent to the ABS controller.
From here, the controller determines the speed of each wheel or axle. This information is sent to the Engine Control Module (ECM). If the ECM detects that a wheel is locked, the ABS kicks in. It operates at a very high speed, and often makes a grinding noise accompanied by a pulsating sensation.
If your vehicle is also equipped with traction control, the ABS sensor helps control the vehicle’s movement in difficult conditions. When traction is lost, the speed of one wheel differs from the other, causing the system to intervene. The problem occurs because the computer reduces the braking force applied to the wheels. When this force is reduced, the wheels regain grip and are able to turn normally again. The same sensors also control the stability control systems in modern cars.
Can you drive with a bad ABS sensor?
If your ABS sensor is faulty, it means that your car’s anti-lock braking system (ABS) won’t be working properly. You can technically drive with a bad ABS sensor, but it’s not recommended. Safety should always be your number one priority when driving, so if you have a bad ABS sensor, it’s best to get it fixed as soon as possible.
Can ABS sensors be cleaned?
You can try cleaning the ABS sensor, but it is quite unlikely that it will solve the problem. Electrical problems and open circuits are the most common reason ABS sensors fail. However, if the ABS reluctor ring is very rusty, it can cause incorrect readings for the sensor.
What causes ABS sensors to go bad?
There are a few things that can cause ABS sensors to go bad. One is dirt and debris accumulation on the sensor or in the connector. This can happen over time because the sensor is mounted in a very exposed area, especially if you live in an area with a lot of dust or dirt. Another possibility is corrosion, which can occur if water gets into the system. Finally, physical damage to the sensor itself can also cause it to fail.
Does the ABS sensor affect acceleration?
Although it is quite unlikely, it’s not impossible. The ABS sensors are also used for the traction control system, and if a wheel gives the wrong wheel speed, it can reduce power to the engine as a safety feature.
If your car is experiencing any of the ABS sensor symptoms above, but you feel like you don’t have the knowledge to diagnose it properly, it’s time to take it to a mechanic.
Due to the fact that the ABS sensors are installed in an area exposed to water and dust, removing the old sensor can be difficult, and if you don’t have the knowledge, you may need some help from an experienced mechanic.
However, if you have good experience working on cars, you may be able to replace the sensor yourself. Replacing an ABS sensor is usually not too expensive, but the exact cost depends on the make and model of your car.
