Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. What Sensors Make the ABS Work?

What Sensors Make the ABS Work?

ABS system sensors

When we are discussing ABS systems it is good to note the year and make of your vehicle because ABS systems have evolved quite a bit over the years, but you also have to know how the ABS system works.

An anti-lock braking system or anti-skid braking system (ABS) is a system that allows the wheels on a motor vehicle to maintain tractive contact with the road surface according to driver inputs while braking, preventing the wheels from locking up and avoiding uncontrolled skidding. It is a computerized system that monitors all the wheels and applies the brakes. It does this at a much faster rate and with better control than a driver could manage.

ABS generally offers improved vehicle control and decreases stopping distances on dry and slippery surfaces; however, on loose gravel or snow-covered surfaces, ABS can significantly increase braking distance, although still improving vehicle control.

The first anti-lock brake systems started out with only having an ABS module (computer), an ABS hydraulic system built into the brake master cylinder, and only had one sensor built into the rear differential of a rear-wheel drive vehicle; this was known as RWAL anti-lock brakes. Automobile manufacturers then went on to put two ABS sensors on the rear wheels and made the hydraulic valving separate from the master cylinder.

Then the anti-lock brake system evolved to having one ABS sensor per wheel, a more sophisticated hydraulic valving system, and computers that would network with each other. Today, the vehicle may have four sensors, one located at each wheel, or the computer may only use the transmission output speed sensor to activate the anti-lock brakes by making the vehicle downshift the transmission or shut down part of the engine. Most of the vehicles on the road today have four sensors, one at each wheel, that you can see by looking behind the wheel at a wire that comes from the bearing area or the axle, which will most likely be your sensors.

Some of the vehicles today have the wires for the ABS going under the carpet in the interior of the vehicle to keep the wires out of the elements. In other vehicles, you will find the wires along the suspension systems. Some are also built into the wheel bearing assy, and if one goes bad you have to change out the whole bearing assembly. I hope that helps you locate where the sensors may be.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...


Related questions

Q: Stalls when shifting and oil leak issue. 2000 Mercedes Benz E55 AMG

First, check to see if the brake light is on when the vehicle is running in park. If the brake lights are on or the brake is pushed at the same time the gas pedal is pushed, you will get...

Q: ABS/CV axle problems after installing new axles.

Hi there. The hubs to the vehicle are designed with the harness in the middle of them for the ABS sensors. You may have installed the wrong CV axles. The replacement CV axles for the vehicle are a different design...

Q: What is cause of yaw sensor malfunction

I'll agree with the shop on this one. The yaw sensor is a very sensitive device designed to measure the sideways force on a car during a turn and it's part of the Vehicle Stabilization System. It has a small...