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What Is an Anti Lock Braking System (ABS)?

Stopping a vehicle in an instant can be challenging, especially on slippery roads.  No one wants to have to hit the brakes suddenly to avoid a collision, but at some point in time it is something each driver will face. This is why having an anti-lock braking system in your vehicle is crucial.

And no matter how experienced a driver you are, it can be a nerve-wracking event. Anti lock braking systems (ABS) in vehicles help provide tracking control and better steering during these events. 

This article will explore how ABS systems work with a semi-truck and other pertinent details about ABS.

How Does an Anti Lock Braking System Work?

Anti lock braking systems were created to help prevent the wheel from locking up when you need to engage the brakes quickly, allowing drivers to steer better in emergencies. This helps restore traction to your tires. 

The technology behind has sensors that detect when your vehicle’s tires begin locking up. At that time, the vehicle will automatically apply and release the brakes to keep your tires from skidding. 

What Vehicles are Required to Have an ABS?

ABS brakes are required by law on new vehicles effective in 2012. The manufacturers of the vehicle are responsible for fitting the anti lock braking systems to their vehicles before they sell them in the United States.

The vehicles that are not impacted by this requirement are vehicles that are older and not originally fitted with ABS. These vehicles do not require an ABS retrofit. 

How Effective is an Anti Lock Braking System?

Anti lock braking systems have been installed on vehicles since the 1980s. Since then, there have been numerous studies to gauge the effectiveness of these systems. 

They have found time and time again that ABS reduces the risk of crashing as it lessens the severity of the impact. They compared the typically recommended full-braking in emergencies, or pumping the brakes manually, by professional drivers to ABS systems with the average driver, and ABS systems continued to be safer. 

What Is an ABS Code?

There is a warning that can be illuminated in your vehicle’s gauge cluster. When the anti lock braking system light is on, it can mean many different things. Either way, it means that there is a problem with your ABS system. 

This could be from needing to be cleaned to your system being fully disabled. For your safety, you should have this warning light looked at immediately.

Four Components of an Anti Lock Braking System

Anti lock braking systems have four major components that work together to help improve steering while braking in emergencies. 


The first component is speed sensors. These sensors monitor how fast the wheels are rotating on the vehicle. 


The next component is the valves. The valves in the brake line block and release pressure on the brakes.


The pumps then control the pressure on the brake drums on demand. They are filled with hydraulic fluid that does the pumping motion so that you can focus on controlling the wheel.


The last component is the controller. This is an electronic control unit (ECU) and it’s regarded as the brain of the system. It utilizes the data it receives from the sensors to determine when to pump the brakes. 

Types of Anti Lock Braking System 

While anti lock braking systems all provide the same safety feature for vehicles, it’s important to note that there are three different types of these ABS systems: 

  • Four-channel or four-sensor
  • Three-channel or three-sensor
  • One-channel or one-sensor

Four-Channel & Four-Sensor

The four-channel/four-sensor anti lock braking system is one of the most common for vehicles on the road. It’s considered the top option because it can micromanage the action of the individual brakes by pulsing only the wheel or wheels that are affected.

Three-Channel & Three-Sensor

The three-channel/three-sensor ABS system has sensors that are in the front and in the rear. The rear sensor affects both of the rear brakes. 

One-Channel & One-Sensor 

Last but not least is the one-channel/one-sensor ABS system. This is the most common in trucks with rear anti-lock brakes. This system has only a single ABS sensor located in the rear axle housing. 

What Happens If the ABS Is Not Working?

There is a warning light in your vehicle that will alert you when your ABS is not working. Malfunctions of the ABS system can occur when a sensor becomes damaged or if there is a problem with your brake system. 

If you have a complete malfunction, you should immediately schedule an appointment to have it repaired. Although it is not technically illegal to drive without ABS, it is considered unsafe, especially if you’re utilizing your vehicle for work. 

The anti lock braking system is a requirement for your vehicle to pass inspection, so it should be repaired as quickly as possible. In the interim, you’ll need to use the old method of pumping the brakes in the event of an emergency.

However, the sooner you can get your ABS system fixed the better. 

What’s the Difference Between a Brake Light and an ABS Light?

There are two different lights that can appear on your vehicle’s dash. The Brake light and ABS light differ. The ABS light does not mean that your entire braking system is failing or could malfunction soon. It just means that there is a problem with the ABS system. 

This could mean that any of the four components, or a combination of all of them, are not working properly. In the event of an emergency stop, you’ll need to pump the brakes to stop as safely as possible. 

However, if your brake light and ABS light are both on, it is a warning that your vehicle is not safe to drive. Your vehicle has a problem with the entire braking system and being on the road puts you and other drivers at risk. 

Safety Reminders with an Anti Lock Braking System

While anti lock braking systems are a great invention and have helped reduce accidents and limit the severity of collisions, there are a few things you should be aware of while using them.

  • Do not pump the brakes. Keep your foot on the brake pedal.
  • Do not assume you have four-wheel ABS.
  • Check your vehicle’s manual to determine what ABS system is installed.
  • You still need to steer to avoid obstacles.
  • Anti lock brakes don’t work well in all conditions. ABS works best on hard surfaces that are slick. They do not work as well on gravel and sand surfaces.
  • Your vehicle will stop faster than anticipated.
  • Understand when your ABS kicks in. You will feel a pulsing, puzzling, or vibrating sensation on the brake pedal.

Safer Driving with ABS

Anti lock brake systems are there to engage when you need them the most. It allows drivers to safely steer the vehicle when an emergency arises while pumping the brakes automatically. 

Take the time to understand which type of ABS brakes are installed on your vehicle to ensure you understand how they’ll operate in case of a quick stop, and always be on the lookout for any warning lights that alert you when the vehicle’s ABS system isn’t operating properly. 

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