ABS and Brake Light On – 6 Main Causes

A study conducted by the Monash University Accident Research Centre in Australia in 2004 revealed that the ABS in modern vehicles reduces the risks of accidents by 18%. Is the ABS of your car working correctly? This article will discuss ABS and brake lights on – 6 leading causes.

The six common reasons for the ABS and brake light on your dashboard are bad wheel speed sensors, low brake fluid level, malfunctioning ABS module, blown fuse, or a turned-off ABS.

If the brake light and the ABS have turned on simultaneously, you can no longer safely drive your vehicle. Should there be a situation where you need to step on the brakes, your car may not stop. Your risk of getting into a car accident is very high. 

Read on to learn more about your dashboard’s ABS and brake lights and why they may turn on simultaneously.

ABS and Brake Light Turning On At the Same Time

abs and brake light on

If the ABS and brake light on your dashboard suddenly turn on at the same time, it could be one of these possible reasons:

  1. Blown ABS fuse
  2. Malfunctioning wheel speed sensors
  3. Low level of the brake fluid in the reservoir
  4. The brake fluid sensor is going bad
  5. Malfunctioning ABS
  6. Turned off ABS

It is a severe potential situation having the ABS and brake light on the dashboard turning on at the same time. You can no longer safely drive your vehicle because of the risk of getting into an accident.

When these lights turn on simultaneously, something is going wrong with the entire braking system of your vehicle. Your car may not stop if you need to in an emergency. You must have your braking system checked by a qualified mechanic as soon as possible.

The cost of fixing this problem is not that high. A good mechanic will be able to fix this issue at the expense of around $100 to $150. The ABS components are easily accessible, so labor costs will not be very high.

But whether the repair cost is high or not, you should still have your braking system checked as this situation seriously compromises the safe operation of your car.

What Is ABS and Its Function?

ABS Means Anti-lock Brake System

ABS is the acronym for the anti-lock brake system. Its function is to prevent you from applying too much pressure on your brakes. If you lock up your brakes, the wheels and the axle will stop turning altogether.

When your car is still running fast, it will start to skid, and you will lose control of your vehicle thoroughly. This is dangerous to be in while your car runs at high speeds.

Improves the Ability to Control the Vehicle

Unlike what most people assume, the ABS does not stop your car faster than a standard braking system. On the contrary, it even adds more to the braking distance when you use it.

But it improves your ability to control your vehicle by enabling you to steer out of the way of a possible car crash and thereby avoid getting into a car crash or getting injured. 

Can Stretch the Car’s Service Life

Additionally, the ABS can stretch the service life of your tires, wheels, brake pads, brake calipers, and nearly every component of your car that is related to or is affected by your braking system.

Standard Feature for Modern Cars

All modern cars now have ABS as a standard safety feature. On your dashboard, a warning light will turn on if this system is experiencing a problem. You must take this light seriously, as it warns you to have your ABS checked or fixed.

Aside from this ABS warning light, your dashboard also has a brake system light. This warning light will also come on if it encounters any issues. When it turns on, it informs you that you must take your car to a service shop so that a qualified mechanic can check or fix it as necessary.

Engaged ABS

There are two things that you need to know about ABS safety.

When you engage the ABS, your brake pedal will act differently. You will feel a pulsating sensation. That is how the ABS tries to ensure that the mechanical system will not lock up.

Once the brake pedal pulsates, don’t release it just yet. If you do, this will signal to the brakes that the danger is past. What you need to do is to keep your foot on the pedal and just let the ABS do its work.

ABS Flashing Briefly

If you have a modern vehicle, the ABS will do a self-test when you turn it on. Once you start the engine, the light will turn on briefly. If your car’s ECU detects a problem in the ABS, its light will stay on. But if this light flashes briefly and then fades off, it is just doing a self-test.

Six Main Causes of ABS and Brake Light Turning On

abs and brake light on but no codes
Bad Wheel Speed Sensor

Why is the ABS and brake light on? The ABS and brake warning lights may turn on simultaneously for various reasons.

Based on actual experiences, here are the main reasons why these lights will come on your dashboard at the same time:

1. Blown Fuse

Like all the other electrical systems in your car, the ABS has its fuse. This fuse protects the ABS from electrical surges that can destroy the system. So, this fuse can blow. If it blows, the ABS warning light will turn on.

Replace the fuse if it blows. When it blows again just after you have replaced it, check if there is a short circuit somewhere in the ABS, in the ABS computer, or the pump motor. You will find the ABS fuse inside the fuse box under the hood or underneath the dashboard.

2. Bad Wheel Speed Sensors

Your car has wheel speed sensors that track the speed of the four wheels as they turn independently of each other. These sensors send the data to your car’s electronic control unit (ECU) or computer.

If the computer detects anomalies in the speeds, the traction control system of your car will shift power to different wheels and make adjustments to compensate. But if one or two speed sensors are dirty or not working, they can send wrong information to the computer.

So, instead of making several adjustments, the computer will disable the ABS, traction control system, or both until the problem is fixed or if you restart your car.

3. Low Brake Fluid

If there is a brake fluid reservoir under the hood of your car, then your vehicle is using a hydraulic braking system. This means the braking system works by using a cylinder that presses against a fluid to close the brake pads so your vehicle can stop.

The brake fluid level must be constant and consistent in a hydraulic braking system. If some of the fluid has evaporated, or if there’s a slow leak in the system, the amount of fluid will be reduced. When that happens, your brakes won’t be able to function correctly.

There are sensors in the braking system that can detect fluid level drops. They will send the information to your car’s ECU, which will dutifully turn the ABS light on to warn you about the situation.

4. Bad Brake Fluid Sensor

The ABS warning light and the brake system warning light can also turn on due to a bad brake fluid sensor. This particular sensor is essential in the correct operation of the ABS. If it malfunctions, it will affect the rest of the system, activating the ABS warning light.

So, it is also essential to have this sensor examined by a competent mechanic. If the sensor is faulty, you need to replace it.

5. Failing ABS Module

The ABS of your vehicle shares some vital components with the traction control system. This traction control system keeps all four wheels of your car on the ground running smoothly.

If it detects that one of the wheels is spinning irregularly, it will not send power from the engine to that wheel until it can establish steady traction again.

This way, your car won’t skid out of control if you accidentally apply too much power. However, since both the traction control and the ABS share a self-check system and a control module, there will be times when the ABS can interfere with the traction control or vice versa.

If there’s an issue with the ABS, the traction control light will also turn on, and vice versa. To fix this problem, you need to have the issue diagnosed and repaired by a competent car mechanic.

6. ABS Turned Off

You may not notice it, but perhaps you or someone accidentally turned off the ABS or the traction control. When you turn off the ABS, it usually turns on its warning light on the dashboard. You will then assume that there’s something wrong with your ABS.

If it is just your ABS light or the traction light that appears on the dashboard, there’s a high probability that someone has just turned off the system accidentally.

Perhaps the switch has been accidentally bumped by you or your passenger.

Again, what would cause the ABS and brake light to come on? When you have activated ABS and brake lights, your braking system has a severe problem. You should pull over or drive to the nearest mechanic.

Is It Safe to Drive With the ABS and Brake System Lights On?

You must pay attention to its ABS and brake system lights when driving your car. They are your first line of defense against collisions and accidents.

When the lights of the ABS and the braking system appear on the dashboard, it does not mean that you don’t have any braking capability. It means that your mechanical brakes are operating independently, and so are you.

If there is an emergency, you can still step on the brakes, and you will be able to stop your car. However, since the ABS and the braking system help you control your car better, you need to have them checked by a competent mechanic as soon as possible.

While you may still have emergency braking capabilities, your car is no longer safe to drive – even for short distances.

When both the ABS light and the brake light appear on your dashboard, your car’s ECU warns you that something is seriously wrong with your car’s braking system. If you insist on driving it, you risk yourself and others.

How to Reset the ABS and Brake Light

abs light and brake light on at the same time
ABS Fuse

There are several fixes you can perform if you have the ABS light and the brake light coming on simultaneously on your dash. This is how to reset the ABS and brake light:

1. Replace the ABS Fuse

This is the easiest fix to this issue. You need to find where the ABS fuse is located. Your car manual will tell you where you can find it. It is usually installed together with the other electrical fuses of your car in the fuse box.

The fuse box can either be under the dashboard or the car’s hood. Refer to your manual for the exact location.

2. Replace the ABS Module

If the mechanic finds out that the ABS computer module is at fault, ask them to replace it. This module is usually located on top of the pump motor. Four to five mounting bolts secure it.

3. Replace the ABS Wheel Sensor

If the mechanic discovers the wheel sensor’s fault, it must be replaced. The mechanic is the best person who can do that.

4. Fix or Replace the ABS Pump

Leaking is the usual problem of the ABS pump. If the mechanic feels they can still fix it, let them fix the leak. However, replace the ABS pump if the leak is no longer repairable. This pump is usually located on the driver’s side.

5. Check the Stator Ring

The ABS wheel sensor has a stator ring that helps the system to monitor wheel speed rotation. If this ring is broken, it will cause the ABS to malfunction. Then the ABS warning light will turn on the dashboard. If upon checking, you find that this stator ring is damaged, then you need to replace it.

Can ABS Be Turned Off?

Frequently Asked Questions

Having your ABS and brake light on but no codes on the dashboard is somewhat scary. If this is the first time you see them on the screen, you will naturally ask why.

For the answer to this question, and other questions you may have on this topic, you may find your answers below:

What Causes the ABS Light and the Brake Light to Come On At the Same Time?

The usual reasons why both the ABS and the brake light appear on your dashboard are the following:

  1. The ABS fuse has blown
  2. Improperly working wheel speed sensors
  3. Low level of brake fluid in the reservoir
  4. Malfunctioning brake fluid sensor
  5. The ABS is not working properly
  6. Someone has accidentally turned off the ABS

Is It Safe to Drive with Abs and Brake Light On?

This is a potentially serious situation. When both lights are turned on, driving your car is no longer safe.

The lights came on because your car’s ECU has detected a severe problem in your braking system. If you insist on driving your vehicle, you risk yourself and people.

Does the Vehicle Lose Its Ability to Stop If the Abs System Is Not Functioning?

No, it does not. If the ABS is not working correctly, you still have mechanical brakes. But it will compromise your safety if you face a difficult braking situation while driving. So, it is better to have your ABS checked as soon as possible to fix its issues.

How Much Does It Cost to Fix Abs Light Problems?

In general, fixing ABS light issues can cost you around $100 just for diagnosing the problem. If you add the labor required to resolve the issue, you can expect to pay from $100 to $150. This problem can be easily repaired because the components of the ABS are easily accessible.

However, your repair cost will increase if there are other related braking problems, such as worn brake pads or damaged rotors.

In Closing: ABS and Brake Light On – 6 Main Causes

There are six reasons why the brake light and the ABS turn on at the same time on your dashboard. The reason could be any of the following:

  1. Low brake fluid level inside the reservoir,
  2. A faulty wheel speed sensor,
  3. A malfunctioning ABS module,
  4. No longer working brake fluid sensor, or
  5. Turned off ABS.

If the ABS and the brake light are turned on simultaneously, it is no longer safe for you to drive your car. Should you encounter a situation on the road where you need to step hard on the brakes, your vehicle may not stop.

So, your risk of getting into a car crash is very high. Don’t drive your car until this issue is fixed.