How ABS Sensor Keeps You Safe

An anti-lock braking (ABS) sensor monitors the speed and rotation of a vehicle’s wheels to help prevent the brakes from locking up during a stop. The sensor works by communicating with an ABS ring, which is mounted to a component that rotates with the wheel. The sensor then sends the wheel speed data to the ABS control module, which uses it to determine when to activate the ABS and how much pressure to apply. 

Here’s how ABS sensors work:

ABS ring

Also known as a tone or pulse wheel, this ring is mounted to a component that rotates with the wheel. This component is often the wheel hub, but can also be the brake disc, CV joint, or drive shaft. 

Sensor

The sensor is mounted next to the ABS ring and can be either a magnetic inductive (passive) sensor or a Hall effect (active) sensor. 

Data transmission

The sensor sends the wheel speed data to the ABS control module. The ABS control module then uses this data to determine when to activate the ABS and how much pressure to apply. 

ABS activation 

If the ABS detects wheel lock, it sends a message to a controller that releases and applies the brake up to 20 times per second. This helps prevent the brakes from locking up and helps the driver maintain control of the vehicle. 

ABS sensors can fail due to clogging from dirt, brake dust, or metallic debris, or exposure to harsh elements.