When the ABS light came on, it presented a moment of discovery. It means there is a problem with the anti-lock braking system.
Sometimes, the problem is easy to fix, and can be difficult. When driving, the vehicle constantly monitors the sensors to ensure everything works as intended.
Among the systems, the car monitors are ABS, or the Anti-lock Braking System. Why is my ABS light on?
The ABS monitors the wheels to ensure they are turning properly and at the same speed; if not, the lights come on. They help the tires maintain contact with the road surface during heavy braking.
The lights remain on until you fix the core issues. Essentially, the lights alert drivers that their safety system is compromised or is no longer active. ABS helps drivers maintain directional stability and control during extreme braking situations.
ABS is common in modern vehicles and decreases accident risks by 18 percent, according to research findings. The system controls the rotational speed of every wheel to make the vehicle move in the desired direction, even if it’s sideways.
What does the ABS Light Mean?
ABS stands for the antilock braking system. The illuminated ABS light in your car’s gauge cluster indicates that your antilock system has been deactivated because of a malfunction.
The ABS uses sensors at each wheel to monitor their rotational speed. A computer monitors the signals from all four wheels and the position of the brake pedal to ensure the vehicle is stable and under control.
If the computer notices any abnormal signals or the lack of a signal from any of the sensors, it will turn the ABS warning light on to alert the driver of an issue. In addition to monitoring the wheel speed sensors, the computer can turn the ABS light on for other reasons, like low brake fluid levels or a blown fuse.
Some ABS systems may flash the light a few times and then leave it on constantly. The number of flashes refers to a trouble code and can help you identify the issue. Refer to the vehicle repair guide or online information to determine what your ABS tells you when it flashes.
Common Reasons the ABS Lights Come On
Many causes could make an ABS light come on. It doesn’t always mean there is a problem with the anti-lock braking system directly. There could also be a problem with other sensors or components it communicates with.
Below are the top 6 causes of an ABS light coming on.
#1. Low Brake Fluid.
The brake fluid has a lot to do with controlling the braking pressure within an anti-lock braking system. There is a brake fluid reservoir which holds the fluid of the anti-lock braking system.
If you need to add or replace brake fluid, make sure to avoid these common brake bleeding mistakes that could compromise your brake system’s performance.
Sometimes there could be a leak from this reservoir, which will cause the fluid levels to drop. Either that or excessive amounts of air may exist within the system.
Either way, it may certainly cause the ABS warning light to illuminate on the dashboard.
#2. Faulty Speed Sensor.
There are speed sensors built into every wheel’s hub, which calculate the movement rate of that wheel. This information then gets transmitted to the anti-lock braking system.
If it turns out that at least one of the wheels is moving too slowly, the anti-lock braking system will increase the pressure of the brake fluid to allow the wheel to move at a normal speed.
But if there is a problem with the speed sensor, the anti-lock braking system will detect that and cause the warning light to illuminate on the dashboard. Additional lights for traction control or stability control (such as “VDC Off”) may also turn on.
#3. Bad Brake Light Switch.
The brake light switch does more than just control your brake lights. It also sends signals to your ABS to let it know when you’re pressing the brake pedal. This information helps the ABS computer coordinate with other safety systems and make proper decisions about when to activate.
When the brake light switch fails, it can send incorrect signals to the ABS module or stop sending signals altogether. The ABS might think you’re not braking when you actually are, or it might receive conflicting information from different sensors. This confuses the system’s logic and can prevent it from functioning properly.
As a result, the ABS computer will typically disable the anti-lock braking system and illuminate the ABS warning light on your dashboard. You might also notice related warning lights for traction control or stability control, since these systems all work together and rely on input from the brake light switch to operate correctly.
#4. Bad ABS Module.
The module of the anti-lock braking system can form corrosion after a while. This is actually one of the most common reasons why there ends up being a problem with the anti-lock braking system.
If the module is corroded, then it can’t obtain information from the wheel speed sensor. As a result, the ABS light illuminates on the dashboard. It doesn’t even take a lot of corrosion to cause this to happen, either. But you will need to replace the module after this happens.
#5. Bulb Check.
Some vehicles will perform what is known as a bulb check on the dashboard. This check is for the driver’s convenience, so they know the bulbs of their vehicle’s warning lights are working properly.
These lights will usually turn off by themselves after a certain amount of time. In some instances, there may be a glitch in the bulb check, which keeps the ABS warning light illuminated after the bulb check is completed.
#6. Worn Hydraulic Pump.
If there is one wheel of a vehicle that moves at a different speed than the other wheels, the wheel speed sensor detects this and then notifies the anti-lock braking system.
Once this happens, the system will activate the hydraulic pump to increase the amount of brake fluid pressure. This will allow the wheels to maintain their traction as they’re touching the ground.
Unfortunately, hydraulic pumps tend to get worn out after years of use. This would certainly cause the ABS light to come on, which means you’d need to replace the pump right away.
#7. Blown Fuse.
Fuses are often overlooked components in your car’s electrical system. They protect your car’s electrical circuits by breaking the circuit when there’s too much current flow. Because of this, they’re a possible cause of your ABS light illuminating.
To check if it’s a blown fuse causing the problem, you can locate your car’s fuse box, which is usually found under the hood or near the driver’s side dashboard.
Look at the fuses related to the ABS and see if any of them have a visibly broken wire or cloudy appearance inside the glass. Replace any blown fuses with new ones to see if the ABS light turns off.
How Do You Diagnose the ABS Problem?
ABS system works with the braking system to maintain control in case of heavy braking in an emergency, like slippery or wet roads. Signs of trouble include a rapid pulsating brake pedal or slight vibrations. To determine the issues, perform the following diagnostic steps.
Step 1
Insert the key in the car ignition and turn it on and off to see if the light comes on the dashboard. Sometimes, this solves the problem as it resets the code stored in the system memory. This is how to reset the ABS light without a scan tool.
In case the issue persists, take the vehicle to an auto shop for a scan to locate and fix the code.
Step 2
If the ABS pulses at low speed, clean the front wheel sensors while applying little pressure. Clean the wheel sensors or take the vehicle to an auto shop for cleaning of the wheel sensors.
Step 3
If the vehicle won’t stop, apply more pressure to the ABS brake. Check the master cylinder brake fluid level and refill it to the marked level if it’s low. Also, it means that air may be in the hydraulic system, resolving the situation by bleeding the hydraulic system.
Replace any broken or loose front-end parts if there is a clunking noise as you press the ABS brakes.
Passive wheel-speed sensor diagnosis
A common ABS failure is classified as dynamic and static. Static failure includes wiring problems and sensor coil failures. Dynamic failures are related to signal quality problems.
Do a visual inspection for the sensor mount, speed sensors, pigtail, and sensor tip in case it’s exposed, and check the connector. For exposed tone rings, do a tooth-by-tooth inspection for damaged or cracked tone rings.
Check the sensor to harness the connector for problems like corrosion, pin problems, or water intrusion. Inspect the ECU connector and pay close attention to pins that may be pushed out.
Check for a loose wheel bearing as it allows fluctuation of the air gap, leading to a false activation or DTC.
Performs ECU diagnosis
Perform generic tests to verify that power and ground are getting to the ECU. The proper operation of ABS depends on the proper grounding of the ECU and the ECU receiving the right operating power.
Locate the ground and power circuits, then perform voltage tests for the power and continuity tests for the ground.
Every new car in the United States has had an ABS requirement since 2013. Automakers are including the standard equipment in other vehicle models made in the late 1980s.
ABS sensors tell your dashboard controller when your wheels stop rotating when the vehicle is in motion. It’s a sign that the brakes have locked up.
The controller then directs a hydraulic valve to release the brake fluid pressure to the wheels to facilitate wheel rotation again. The process repeats every time until the vehicle stops or your foot is off the brake pedal.
How Do You Fix If the ABS Light Comes On?
You know there is a problem the moment the ABS light comes on. How to fix the ABS light depends on the nature of the ABS problem.
The vehicle can exhibit strange behavior when slowing down in a corner. Also, the vehicle blows past the downhill turn and skids straight, and the steering wheel cranks all the way into that downhill turn.
The ABS performs a self-test each time you insert the car key and turn on the ignition. If there is insufficient data during the self-test, or the hydraulic valve or pump stops working, the ABS light comes on.
ABS relies on the proper operation of the conventional braking system. So, if other parts of the braking system are working normally, you will still enjoy normal braking without the ABS.
#1. Replace the ABS fuse.
If the ABS fuse is blown, replace it. Locate the ABS fuse panel under the dashboard and replace it.
#2. Fix a leaking ABS Pump.
Replace the ABS pump module after ascertaining it’s leaking. The pump is on the driver’s side.
Trace the black wire from the bleed ABS module to the driver-side fender and unbolt it. Use a wire brush to clean the bolt and lug. Remove all the grime from the parts to leave them shiny and clean.
Apply Di-grease to the lug and bolt on both sides and in the bolt hole. Apply more Di-grease on the bolt and lug surface, including the wire housing. Ensure all metal surfaces are covered in grease.
#3. Replace the ABS wheel speed sensor.
Test the ABS wheel sensor or scan it for the presence of error codes such as C0050, C0046, C0045, C0041, C0040, C0035, etc.
The error codes mean your car sensors are not plugged in or need replacement because of a short circuit. Replace the sensor using basic tools like a work light, screwdrivers, pliers, and other supplies in your toolbox.
#4. Replace the ABS computer module.
ABS controller monitors the wheel rotation speed and can sometimes go out. The computer module is on top of the pump motor and held by 4-5 mounting bolts.
If you hear a humming brake noise or the ABS light remains on after turning off the key, then it means one of the valve control coils is already burned out and needs immediate replacement.
#5. Finally, check the stator ring.
The ABS wheel sensor works together with the stator ring to monitor wheel speed rotation. If the stator ring is damaged, it can cause a malfunction of the ABS system.
Check to ensure the stator ring is not damaged or dislodged, resulting in missing teeth, resulting in the activation of the ABS light. A damaged tooth on the stator ring provides intermittent signals to the front wheel sensor.
The ABS wheel sensor sends a different error code that looks like a reluctor ring with teeth on it. As the wheel rotates, the teeth pass the magnetic speed sensor, giving a reading in miles per hour.
However, the controller sees the wheel as not moving and pulses out the brake calipers on the wheel.
The erratic signal turns on the warning ABS light, and the ABS system may go active and pulse your brakes at low speeds. Physically inspect the stator ring to ensure there are no missing teeth, which means no warning light.
FAQs.
Q: Is it safe to drive a car with an ABS light on?
Yes, it is safe to drive your vehicle carefully with the ABS light on. The illumination of the ABS icon does not impact your car’s functionality or normal braking, which is why you can still drive your car with the ABS light on. However, I recommend you get the vehicle checked as soon as possible and fix the problem.
There are also instances where it is unsafe to drive when the ABS symbol comes on with the brake system warning light.
Driving when both lights are illuminated simultaneously is dangerous. The rear wheels could lock more quickly in an emergency stop than under normal circumstances.
Have the vehicle towed to a dealer or repair shop to inspect the brakes immediately.
Q: How much does it cost to fix the ABS?
It will cost approximately $200 if you factor in the cost for ABS diagnosis and labor costs. However, the estimate doesn’t include taxes and fees and varies depending on your location.
However, if you have to replace the ABS, you can pay an additional fee of $200-950, depending on the ABS module part. Many garages will fix your ABS for between $340-1100 in total.
Q: Can Low brake fluid cause the ABS light to come on?
Yes, an ABS light comes on when there is a low brake fluid level in the ABS fluid reservoir. The warning light means you have an abnormally low fluid level.
Turn off the engine and restart by turning it on again to see if the warning clears. If not, check if the light is intermittent. If so, it means the brake fluid level is slightly low.
Q: Can worn brake pads cause the ABS light to come on?
No. Worn-out brake pads don’t cause the ABS light to come on. The light is triggered by a low brake fluid level, an abnormal wheel sensor, and a blown fuse.
However, it’s good to replace worn-out brake pads to improve your braking as a safety precaution. Replace worn brake lines to improve your car’s braking efficiency.
Q: What can cause ABS to fail?
ABS rarely malfunctions unless the ABD controller is malfunctioning because of one or more sensors or faulty sensor wiring.
The most common cause is the contamination of sensors by corrosion, debris, or metal shavings. You will only notice a failure the moment you slam the brakes and notice the wheels are locking up as you drive.
Final Thoughts
Always be observant when driving and listen to abnormal brake noises that indicate a problem. Observe the ABS module or your dashboard for a warning light that shows performance issues.
American-built cars don’t need code clearing. Some Japanese and European-built vehicles may require code clearing using an ABS code reader.
If the ABS warning light still remains after code clearing, it means there is still a problem that needs fixing.
To fix the issues, you need various supplies and tools like repair manuals, toolboxes, safety equipment, cleaning supplies, floor ramps, jacks, and stands. You also need parts replacement, like the controller/computer module, wheel speed sensor, and ABS fuses.