WHAT IS A WHEEL SPEED SENSOR AND HOW DOES IT WORK?
                     WHAT IS A WHEEL SPEED SENSOR AND HOW 
DOES IT WORK?
Mark Sanford
Writer at Brake System
University providing advice, reviews and information on 
brake system components including 
brake line repair kit advice at break system university/
brake line replacement kit reviews at break system unive
rsity
Newer model cars have an anti-lock braking system (ABS) for safety 
purposes. There is an ABS wheel sensor located at the wheel hubs on a 
vehicle. Their function is to monitor the rotation of each wheel and to then 
override manual braking of the vehicle in wet or slippery conditions. The 
ABS sensor also compares the speed of each wheel to each other and it 
can engage if the wheels are not all turning in continuity.
HOW DO SPEED SENSORS GENERATE A SIGNAL?
Speed sensors contain a magnet wrapped in a coil and a sensor ring made 
with teeth that is mounted around the vehicle’s CV joints. The magnet and 
the toothed ring create a signal as an electrical field from them contacting 
each other. The signal measures the number of pulses per second created 
by the electrical field between the magnet coil and sensor ring. This signal 
is then converted to a digital signal and sent to the ABS controller. The 
controller counts the number of pulses to determine the wheel speed and 
then evaluates whether the ABS system should engage to override manual 
braking. When the sensor notices that the wheel locks up during hard 
braking, it will automatically release your brake pressure momentarily and 
then pump the brakes for you at a very rapid pace. When it engages, the 
driver will feel it applying the brakes.
SIGNS OF A FAILING ABS SPEED SENSOR
The most common sign of a faulty ABS wheel sensor is that you will see a 
warning light on your dashboard. You may also have your speedometer 
disabled and notice that you have lost your anti-lock brakes when the 
computer in the system turns it off. You may also notice that your wheels 
lock up in hard braking and you will skid on a wet road or in the mud.
HOW TO REPLACE AN ABS BRAKE SENSOR
Open the vehicle’s hood and take off the negative battery cable from the 
negative terminal. This action cuts power to the ABS system. Loosen the 
wheel’s lug nuts with a tire wrench 1/4 turn. Raise the vehicle onto a jack, 
remove the lug nuts and pull the wheel off the wheel hub assembly. Locate 
the ABS sensor on the wheel hub. It’s a small black box. Unplug the wires 
from the ABS sensor, remove the mounting screws and pull the sensor off. 
Replace the sensor and reverse the steps to complete installation.
THE IMPORTANCE OF QUALITY ABS BRAKE SENSORS
You should always use the highest quality ABS wheel speed sensors, as 
they are a safety feature for any vehicle. They affect anti-lock brakes (ABS), 
the traction control system (TCS), the ESP that prevents swerving and 
skidding, and the hill start assist and adaptive cruise control (ACC). The 
quality sensors detect wheel speeds as low as 0.1 MPH, detect both 
forward and backward movements, and have a reduced sensitivity to 
interference in the electromagnetic field that they produce. Quality 
sensors will also be made more rugged and waterproof to protect them 
from moisture, road contaminants, chemicals, and dirt, so they will 
perform properly for a longer amount of time. The engine wire harness 
should have a watertight connection to perform properly. It just makes 
sense to choose quality ABS wheel speed sensors because they are a major 
component in your safety in any vehicle.
About Brake System U
Brake System University is a micro site giving advice, reviews, and technical 
information on various brake system components like brake lines, brake 
line kits, and ABS sensors. Brake System University connects you to high 
quality, genuine brake system replacement parts including  replacement 
brake lines, replacement ABS sensors, replacement brake line kits that 
have been tested and reviewed by experts. If you want to replace any 
component of your brake system, then this 
site(https://brakesystems.autopartsu.com/) will helps you in choosing the 
right component. Brake System University connects you to trusted reviews 
and referrals to help you easily make a purchase decision.