Skip the auto shop - Our mechanics make house calls

How Anti-Lock Brakes Work

How Anti-Lock Brakes Work

An anti-lock brake system (ABS) is a braking system that is made to allow a vehicle to maintain traction with the road when braking. Braking is controlled by driver input via the brake pedal, and older braking systems response to a driver braking suddenly or with intense pressure was sometimes to lock up or skid. The ABS is meant to prevent the wheels from locking up or from unnecessary skidding while braking. The automated system uses the principles of both cadence and threshold braking, which were previously practiced by skilled drivers with early generation braking systems. Modern ABS accomplishes these principles with better control and much faster than a driver could.

Today's anti-lock braking system gives the driver better vehicle control and reduces stopping distances on slippery and dry surfaces. However, on loose gravel and snow, anti-lock brakes can increase stopping distance, though the improved vehicle control remains the same.

Components of the ABS

  • Speed sensors: Speed sensors are also called wheel sensors or wheel speed sensors. This part uses a magnet and a wire to generate a signal that is sent to the sensor.

  • Valves: Each brake controlled by the ABS has a brake line and a valve. The valve has three positions, controlling the amount of pressure exerted on each brake, to minimize wheel lock or skidding.

  • Pump: This piece of the system is used to restore pressure to the brakes after the valve has released the pressure. As the pressure applied by the driver decreases, the pump will help to equalize the pressure in the brake lines.

  • Controller: An Electronic Control Unit (ECU) receives the information from the wheel speed sensor and uses that information to perform the task of applying the brakes with the proper amount of pressure needed.   

These pieces work together to keep proper pressure in the brake lines to help stop a vehicle from skidding or experiencing wheel lock when trying to stop suddenly or in bad weather.

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

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: How do I turn on and off the fog lights?

The fog lights are controlled by a large button that doubles as the headlight switch. The headlight switch is a circular switch to the left of the steering wheel. It can be rotated to turn on the headlights, but if...

Q: Vehicle undriveable

Hi. The yellow lamp is likely the Traction Control System warning. It would make sense because the traction control system is directly related to the ABS and brake system. It sounds like your Escape has some braking and stability issues....

Q: Car vibrating after I heard a loud noise while using the brakes in reverse.

It sounds like something may have broken internally within the transmission. I would recommend having your vehicle inspected by a transmission expert to get to the bottom of the issue. If brake applications still feel normal, but the vehicle vibrates...