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Braking Basics: What Is ABS And How Does It Work?

A car's brake light. Ever wondered what ABS is? Here's everything you need to know about anti-lock brakes.

Hundreds of people are injured or killed in car accidents daily, with far more prevented thanks to cutting-edge safety equipment. Modern cars come with an anti-lock braking system (ABS), which have been available for decades but only mandated in recent years. Understanding what is ABS and its effectiveness may influence your used car purchase decisions.

What Is ABS?

An ABS light on the instrument panel.ABS is a computer-controlled system that works with your vehicle’s brake system. Wheel sensors notify the computer module when the wheels stop rotating while the car is in a forward motion, which also means the brakes have overpowered the traction within a given wheel.

Thus, the computer immediately notifies the hydraulic valve to discharge a measure of brake fluid pressure to get the wheel to begin rotating again. This process repeats itself many times a second until you lift your foot off the brake pedal or when the vehicle comes to a full stop. In other words, ABS prevents the wheels from locking, while ensuring tractive contact with the road surface.

How Do We Know It Will Work?

Like any system, ABS must be checked regularly to ensure it performs as expected. Fortunately, your vehicle does a self check each time the ignition is engaged. The computer promptly checks the system and if all is well, you won’t be informed.

It is when the system malfunctions when notification in the form of a warning light is prominently displayed on the dashboard. Typically, the light is illuminated if the computer detects a valve or hydraulic pump isn’t working. This does not mean you cannot drive your vehicle. You can, but you must understand that braking assistance is not available until you have your vehicle successfully serviced.

Where Is ABS Used?

You’ll find ABS on some passenger vehicles dating to the 1990s: cars, pickup trucks, vans, and utility vehicles. As of September 1, 2013, all newly built passenger vehicles must come with ABS and electronic stability control. Some motorcycles have ABS, although it isn’t required. Since March 1, 1997, the federal government began requiring new tractor-trailers and most school buses to come with ABS.

Passenger vehicles with the system will temporarily flash an ABS or anti-lock light when the ignition engages. The light automatically goes off, unless there is a problem. Your owner’s manual is also a place to look for that information.

An important visual check will confirm that an ABS pump is present. Lift the hood and look for the brake master cylinder. The unit will be found nearby with one or two brake lines connecting the two. You can also look behind the front wheels, which will reveal a flexible rubber brake hose connected to the brake caliper. Further, an attached wire to the speed sensor found in the hub area offers another confirmation of ABS. If your vehicle doesn’t have ABS, only the flexible brake line would be present.

How Many Lives Are Saved?

ABS, especially when working in conjunction with stability control, saves lives. The number saved annually isn’t known, but a reduction in accident severity likely is apparent, at least to drivers.

Your car’s ABS system is crucial, because it allows you to brake as hard as possible, while maintaining traction. You won’t notice ABS every day, but if you find yourself in an emergency situation, it could help you avoid an accident.

Check out all the brake system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on what is ABS, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Pixabay.

Matthew C. Keegan View All

Matt Keegan has maintained his love for cars ever since his father taught him kicking tires can be one way to uncover a problem with a vehicle’s suspension system. He since moved on to learn a few things about coefficient of drag, G-forces, toe-heel shifting, and how to work the crazy infotainment system in some random weekly driver. Matt is a member of the Washington Automotive Press Association and is a contributor to various print and online media sources.

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