Since 2013, all new cars in the U.S. have a safety system called Anti-lock Braking System (ABS). This technology helps prevent your wheels from locking up when you brake hard, giving you more control.

The ABS control module is like the computer that runs this whole system. It tells the brakes on each wheel what to do. This module might also be in charge of other safety features like traction control (stops your wheels from spinning when you accelerate), stability control (helps keep you from skidding), hill start assist (prevents rolling backward on hills), and even adaptive cruise control (automatically keeps a safe distance from the car in front).

Simple Signs of a Failing ABS Module

If the ABS control module isn’t working right, you might notice several things:

Multiple Warning Lights On: A bad ABS module can light up various warning lights on your dashboard, like the ABS light itself, the regular brake light (usually red), the traction control light, and sometimes others.
ABS Doesn’t Work: The main job of the ABS module is to make the anti-lock brakes work. If the module fails, your brakes might act like older, non-ABS brakes and could lock up during hard braking.
ABS Turns On Randomly: On the flip side, a faulty ABS module might also cause the anti-lock brakes to kick in even when you’re not braking hard, leading to a weird pulsing feeling in the brake pedal.
Traction Control Stuck “On”: If the ABS module can’t make good decisions, your car might go into a safety mode where traction control stays on all the time, and you can’t turn it off.
Driver Assistance Features Stop Working: Features like automatic emergency braking, adaptive cruise control, and other similar systems might not work if the ABS module is broken because they often rely on the information and control provided by the ABS system.

How to Fix the Problem

Sometimes, a problematic ABS module just needs to be reprogrammed (like updating the software on a computer). Certified mechanics have the tools and information to do this.

If reprogramming doesn’t work, the module will need to be replaced, which can be expensive. Sometimes, the module is a separate part, but other times it’s built together with the ABS hydraulic control unit (the part that actually controls the brake fluid). In some cars, it’s even combined with the brake master cylinder and brake booster, meaning all those parts might need to be replaced together.

After replacing the ABS module, it might need to be programmed or calibrated to work correctly with your car. And if it was replaced along with the hydraulic unit or master cylinder, the brake system will need to be bled to remove any air.

How ABS Systems Work (The Basics)

To understand what the ABS module does, it helps to know the basics of how ABS works:

Wheel Speed Sensors: These sensors measure how fast each wheel is spinning and send this information to the ABS control module.
ABS Control Module (The Brains): This computer receives the speed data from the wheels. If it senses that a wheel is about to lock up during braking, it tells the hydraulic control unit what to do.
Hydraulic Control Unit (The Muscle): This unit has valves (called solenoids) that can adjust the brake fluid pressure going to each wheel, based on the signals from the ABS control module. If a wheel is about to lock, the module tells the hydraulic unit to reduce the pressure to that wheel for a moment, allowing it to regain grip and prevent skidding.

Most traction control systems use the same parts to prevent your wheels from spinning when you accelerate too quickly.