ABS Light: Meaning, Causes (& Is it safe to drive with?)

The ABS system prevents you from locking the wheels and therefore retains the ability to handle the car in an emergency braking. Here's what it means and what causes it.

abs light

Did your ABS Light appear on your dashboard suddenly out of nowhere? You are not alone!

The purpose of the ABS is to prevent you from locking the wheels in a panic situation, helping you keep the steering ability.

But what causes the ABS light to come on, and is it dangerous to drive with? Let’s find out!

What does the ABS light mean?

The ABS warning light indicates an issue with your anti-lock braking system and is therefore temporarily out of function. It could be a bad ABS sensor or ABS tone ring causing it, for example.

ABS stands for anti-lock braking system and helps you not lock the wheel if you panic brake in an emergency. If you lock the wheels entirely, you will not be able to steer at the same time.

If you have been driving an older car without ABS, you have probably felt this on slippery surfaces. But what can cause the ABS light to come on? Let’s find out!

7 Common Causes of an ABS Light

The most common cause of the ABS warning light is a bad ABS speed sensor or a bad ABS tone ring. It can also be caused by a faulty brake light switch, broken ABS pump, or faulty wirings.

There are many parts integrated into the ABS and, therefore, also many parts that could fail.

Here is a more detailed list of the most common causes of an ABS light on your dashboard.

1. Bad ABS sensor

abs sensor in hand

The ABS sensor feels the speed of your wheels. In most cars, there is one wheel speed sensor installed on each wheel. It happens that these ABS sensors fail and start reading the wrong values.

When a speed sensor slightly reads wrong values, you might feel it as your brake pedal pulsate while you try to brake. If the wheel speed sensor is sending completely faulty signals – the ABS warning light will come on.

Learn more about bad ABS sensors here: Bad ABS Sensor Symptoms

2. Bad ABS Tone Ring

broken abs ring

The ABS tone rings are another part that helps the ABS control module know each wheel’s speed.

The ABS sensors read the ABS tone rings’ signals, which are most often installed around the driveshafts but can also be located as a part of the wheel bearings.

Learn more about bad ABS rings here: Bad ABS ring symptoms

3. Faulty or Broken Wires to ABS Sensor

abs broken wiring

As you might know, your vehicle’s suspension bumps up and down and side to side while turning. The ABS sensor is located on the wheel hub, which means they need a cable to the ABS control module.

This cable between the wheel hub and the car’s body will bend probably millions of times in a car’s lifetime. Sometimes it happens that the wires get worn and will break off.

4. Faulty Brake Pedal Sensor / Light Switch

brake light switch

The brake light switch sensor helps the ABS module know when you touch the brake pedal, knowing when to start the ABS pump.

If this brake light switch sends a faulty signal to the abs module, it might light up the ABS warning light and store a trouble code.

5. Faulty ABS Pump

abs pump

The ABS pump is an integrated part of the ABS control module and is used to pump brake fluid to the brake calipers to control them.

The ABS pump has a tough life, and sometimes it happens that it will wear out and get damaged. The good thing is that you can often replace just the ABS pump if you can find one for your car.

Sometimes you can’t replace just the ABS pump, so you must buy a complete ABS unit.

6. Faulty ABS Solenoid valves

abs control unit

Inside the ABS unit, electric valves open and close the brake calipers’ pressure, not letting you put too much pressure on the brake calipers.

It happens that these ABS solenoids fail, and in this case, you do often have to replace the whole ABS unit since they are located inside of it and are not replaceable.

Most of the time, if you buy the ABS pump part, you will also get the housing with the valves inside, but you should always double-check this before the purchase.

7. Faulty ABS control module

abs control module

The last part of the ABS system is the ABS control module. This part is also installed on the ABS unit, and sometimes it happens that it fails. This control module controls everything that has to do with the ABS system.

It is often possible to replace just the abs control unit, but you should know that you often have to reprogram the new control module to your car. This is often something that just authorized dealers can do.

RELATED: Slip Light – What Does It Mean & Causes

Is it safe to drive with the ABS light on?

abs brakes car

It is not safe to drive with the ABS light if you are not experienced driving cars without anti-lock braking system.

The ABS system helps you to steer at the same time as you are pushing the brake hard. Without experience, you will lose the steering ability in a panic situation.

When your ABS light is on, it indicates a problem in your ABS, and it will shut your ABS off completely. If your ABS light appears when you are out and driving, you should drive your car to a mechanic workshop as fast and calmly as possible. You should not keep driving your car with the light on if you do not feel comfortable.

Written by:

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. He has also been a motorsport (drifting) driver for over 5 years.