ABS has protected countless lives since it was invented. But sometimes, the ABS system might be faulty. If your anti lock brakes come on when stopping, you need to dig deeper to find out the reason.
Sometimes you might have noticed that your anti lock brakes come on when stopping your car, even though you were neither skidding nor were your wheels going to lock.
This indicates that there is a problem in the braking system, and you need to address it immediately. For instance, there can be problems in the ABS module, or your brake fluid might be very low.
Let us discuss more about anti lock braking systems and why your ABS system might be kicking in on every brake. Keep reading to understand why this happens.
What Does an ABS system do?
When you drive your vehicle on the road, and suddenly an obstacle comes in the way, you might try to press the brakes as hard as possible. But in earlier days, doing so could have been fatal.
It would have locked your car’s wheels. Your vehicle’s tires would have lost traction, and it would start to skid. It takes a long time to stop your vehicle when you lose control over the steering since a car is a very heavy object accelerating at a fast pace.
You may end up hitting the obstacle, or your vehicle may skid off the road, which could be even more dangerous. It would have put your life in danger.
Thankfully today, the anti lock braking system is used in almost all modern vehicles. The system helps prevent the wheels from locking up when you apply the brakes, drive on wet or slippery surfaces, or while taking a turn.
This stops your car from skidding, and you have better control over your vehicle. With better control, you can stop the car more quickly. You can move your car in the desired direction, which helps enhance your safety.
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What Are The Components Of the ABS System?
The primary components of the ABS are as follows.
#1. Wheel Speed Sensor
The wheel speed sensor is used to measure the speed of the wheel. Whenever the vehicle wheel rotates, it induces a magnetic field in the sensor.
Any variation in this magnetic field generates a voltage in the sensor, and that voltage is sent to the Controller. The Controller understands the speed of the wheel by reading the voltage.
The brake lines which control the antilock braking system have valves in three positions.
- Valve 1: The valve that allows the pressurized brake fluid to move to the brake pads and squeezes the rotor in the open position.
- Valve 2: The valve that blocks the brake line and separates the brake from the master cylinder in block position.
- Valve 3: The valve that releases pressure from the brake.
There needs to be a way to put back the system’s pressure as the valve releases some of the pressure from the brake. The pump does this work effectively.
The Controller comprises an Electronic control unit. It receives information from the wheel speed sensor located on each wheel, and takes decisions regarding operating the rest of the components.
How Does ABS Work?
- When the electronic control unit(ECU) gets the information that there is a sudden decrease in the speed of the wheel, it sends a signal to valve 2, which makes it close. So this decreases the pressure in the brake pad and prevents your car’s wheel from locking.
- As the wheels are not locked, they will start accelerating again. The wheel speed sensor again sends the information to the Electronic controller unit. This time ECU opens valve 1. As a result, the pressure in the brake pad increases and finally comes in contact with the rotor and tries to stop your vehicle. The speed of your car’s wheels gets reduced.
- So in the first case, it accelerates the wheel’s speed, and in the second case, the ABS mechanism decreases the wheel’s speed. Isn’t it confusing? Well, applying and releasing brakes happens more than 15 times in a second when you apply brakes all of a sudden or while turning on a road. It prevents your car’s wheels from locking and eliminates skidding. You can steer your car properly and this greatly reduces the risk of colliding with objects on the road. It saves you from deadly accidents.
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Why Do ABS Brakes Come On While Stopping Normally?
There can be many reasons for the ABS brake coming on while stopping. I am listing some of them below.
#1. Low Brake Fluid
The brake fluid plays a crucial role in maintaining pressure in the antilock braking system. The brake fluid is drawn from the reservoir and is compressed in the master cylinder.
After that, it moves its way through calipers and exerts pressure on pistons. The pistons push the brake pads toward the rotor or disc and stop the vehicle.
There may be brake fluid leakage from the brake lines, which has caused the level to drop by a significant amount. Secondly, there may be so much air in the brake fluid, significantly affecting your vehicle’s braking system.
But if there is significantly less brake fluid in the reservoir, brakes cannot be applied at the right time. The ABS module cannot balance the brake pressure equally on each wheel, increasing skidding and other issues.
The wheels will not decelerate their speed. So, it may be the reason for the ABS brake light coming on while stopping.
Symptoms Of Low Brake Fluid
- The brake pedal becomes too hard to push.
- Your brake becomes noisy. You may hear a grinding sound similar to the sound produced in your vehicle when there are damaged brake pads.
Fill the reservoir with brake fluid
#2. Faulty Wheel Speed Sensor
The wheel speed sensors are located on each wheel hub and send information to the Electronic control unit. The ECU in your vehicle controls numerous systems in your car, including ABS.
If the ECU finds that one of the wheels is moving slowly compared to the other three wheels, then it releases the brake fluid so that all the wheels will move at the same speed. It helps our vehicle to continue gripping the road.
But sometimes, the sensors can malfunction, which results in the ABS brake light coming on when stopping. As the wheel sensors are located very close to the wheel, they can be damaged by continuous heat, or some of its vital parts may be damaged by debris.
Symptoms of A Faulty Wheel Speed Sensor
- Your vehicle loses traction
- Your car will take quite a long time to stop.
If the wheel sensors are entirely damaged, replace them with new ones.
#3. Damaged Hydraulic Pump
The hydraulic controls the pressure of the brake fluid in the antilock braking system. But sometimes, it might have gotten damaged, or there may be too much dirt in the brake fluid, which causes the pump not to function properly. A damaged hydraulic pump may be why the ABS brake light comes on while stopping.
- Poor braking performance
- May skid your vehicle on the road
If the mechanic finds the hydraulic pump is damaged, then better replace it with a new one.
#4. Faulty ABS module
The ABS module may become faulty with time, mainly because of damaged wire. The wires may go bad due to corrosion, which delays communication between the wheel’s speed sensor and the ABS module.
- You will hear a clicking noise while stopping your vehicle
- Your brake may lock during dangerous driving.
- The brakes of your vehicle will not work properly. It may get worsen with time.
Your vehicle needs a bit of rewiring. So take your car to the nearest mechanic. He will correct all the wiring problems and will solve your problem.
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Frequently Asked Questions
#1. Why do my brakes feel like ABS is kicking in?
When the ABS starts kicking in, it indicates the weak signal from the wheel speed sensor to the ECU.
#2. What activates the antilock braking system?
The antilock braking systems are activated when you suddenly apply hard brakes, take a turn, or are on slippery and wet roads that prevent the wheels from locking.
#3. How much does it cost to fix an ABS actuator?
The average cost of replacing an ABS control module lies between $911 and $954. The actuator will cost you $309 to $350. The labor costs might be between $103 and $150.
Remember this range does not include any taxes and any other fees.
#4. How do I reset my anti lock brake system?
Disconnect the positive cable of your battery. Hold the brake pedal down to drain the electrical system of your vehicle. It will result in resetting the central computer.
Now connect the positive cable back to the battery. It will help in restoring power. If there is no other problem with the ABS, reset your anti lock braking system.
If the ABS light comes on after resetting the computer, there is a problem with the wheel speed sensor. These sensors are mounted on the hub of the wheel. You need to unmount it and unplug some wires and then mount another new wheel speed sensor.
If the ABS light still comes on, use the ODB code reader to detect the problem. But if you don’t have one, it’s better to take your vehicle to the nearest mechanic.
A Few Final Words
The antilock braking system has immense benefits like it prevents your car from skidding and increases your safety while driving on the road. But sometimes, you find the ABS light turning on while driving which indicates there are issues in the system.
I have listed above some reasons that may help you detect the problem and find a solution for it. But if you are not confident enough to correct the ABS, you better take your car to the mechanic. He will inspect the problem and correct it.
Thank you for reading the article, we hope this answers all your questions regarding ABS and why it may be coming on without any reason.