Why ABS Light Came On? Causes, Fixes & Safe Driving Tips

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’s ABS, or Anti-lock Braking System, is monitored. Why is my ABS light on? 

The ABS system 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 Essentially, the lights alert drivers that their safety system is compromised or is no longer active.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 reduces accident risk by 18 percent, according to research. The system controls the rotational speed of every wheel to make the vehicle move in the desired direction, even if it’s sideways. 

Common Reasons the ABS Lights Come On

What does abs light mean? It means you have any of these issues:

 A blown fuse

ABS fuse functions like other electrical systems. The fuse protects the ABS system and can blow during an electrical surge. Check the fuse; if it’s blown, replace it with a new fuse. If the fuse blows again, then there is a short circuit in the ABS system; check the pump motor or ABS computer.

The fuse is located in the fuse panel under the dashboard or in the power distribution center under the hood. 

Low brake fluid

The ABS light on the dashboard is a sign that either the brake fluid escaped from the system through a leak or evaporation or that the fluid level dropped but wasn’t picked up by the sensor. If the brake fluid level drops and the ABS light comes on and off, the sensor needs to be replaced, as it’s defective. 

The ABS fluid level sensor is vital to the anti-lock braking system’s overall functioning; a failure can affect the rest of the system. Therefore, if you suspect the fluid level sensor is faulty or the ABS light came on, perform a thorough vehicle diagnosis or contact an expert mechanic to determine whether the ABS fluid level sensor needs to be replaced or if there is a different issue to address. 

Abnormal signals arising from wheel sensors.

Your ABS uses the brakes to stabilize the vehicle in slippery situations. A problem with this system is that the vehicle may not stop quickly. The abnormal wheel sensor light is a precautionary warning mechanism that you have a problem that needs urgent attention. Usually, the ABS light automatically activates when you engage in emergency braking, when the wheels lock.

However, if the ABS fluid level sensor fails and the fluid level drops below a specific point, the vehicle becomes prone to unexpected wheel lock. The vehicle’s tires skid when the ABS system malfunctions and you engage heavy braking. Essentially, the vehicle takes more time to come to a stop. This is what causes the ABS light to come on and go 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 into the car ignition and turn it on and off to see if the dashboard light comes on. Sometimes this solves the problem by resetting the code stored in system memory. This is how to reset the ABS light without a scan tool.

If the issue persists, take the vehicle to an auto shop for a diagnostic 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, which can be resolved by bleeding it.

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

ABS failures are classified as dynamic or static. Static failure includes wiring problems and sensor coil failures. Dynamic failures are related to signal quality problems. 

Do a visual inspection of the sensor mount, speed sensors, pigtail, and sensor tip (if 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 connector for problems such as corrosion, pin issues, 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 the air gap to fluctuate, 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 ECU being properly grounded and receiving the correct operating power. Locate the ground and power circuits, then perform voltage tests on the power circuit and continuity tests on the ground circuit.

Every new car in the United States has had an ABS requirement since 2013. Automakers have been including standard equipment in other vehicle models since 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 brake fluid pressure to the wheels, facilitating 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. The solution to fixing 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.

Replace the ABS fuse.

If the ABS fuse is blown, replace it. Locate the ABS fuse panel under the dashboard and replace it.

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 greased.

Replace the ABS wheel speed sensor.

Test the ABS wheel sensor or scan it for the presence of error code 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 work light, screwdrivers, pliers, and other supplies in your tools box. 

Replace the ABS computer module.

ABS controller monitors the wheel rotation speed and can sometimes go out. The computer module is mounted on top of the pump motor and secured with 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.

Finally, check the stator ring.

The ABS wheel sensor works with the stator ring to monitor wheel rotation speed. If the stator ring is damaged, it can cause the ABS system to malfunction. 

Check to ensure the stator ring is not damaged or dislodged, as missing teeth can activate the ABS light. A damaged tooth on the stator ring intermittently signals the front wheel sensor. The ABS wheel sensor sends a different error code that appears to be a reluctor ring with teeth. 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 the brake calipers on it. An erratic signal triggers the ABS warning light, and the ABS system may activate 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

Is it safe to drive a car with an ABS light on?

Yes, it’s safe. The car’s brakes will still work normally during normal braking, even with the ABS light on. However, the brakes will lock up in heavy braking, forcing the wheels to skid. Your ABS system is very important during winter, when your wheels can lock up under heavy braking on ice. 

Driving with the ABS light on during winter is dangerous, as your vehicle can’t handle heavy braking in emergency situations. The safety feature protects you from accidents and shortens your braking distance, giving you control over the steering. 

How much does it cost to fix the ABS system?

It will cost approximately $200, including the cost of ABS diagnosis and labor. However, the estimate doesn’t include taxes and fees and varies depending on your location. 

However, if you have to replace the ABS system, you can pay an additional fee of $200-950, depending on the ABS module part. Many garages will fix your ABS for between $340 and $ 1,100 in total.

Can Low brake fluid cause the ABS light to come on?

Yes, an ABS light comes on when the brake fluid level in the ABS fluid reservoir is low. The warning light indicates an abnormally low fluid level. Turn off the engine, then restart it 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. 

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 a good idea to replace worn-out brake pads to improve your braking and enhance safety. Replace worn brake lines to improve your car’s braking efficiency.

What can cause ABS to fail?

ABS rarely malfunctions unless the ABD controller is defective due to 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 the wheels lock up as you drive. 

Final Thoughts

Always be observant when driving and listen to abnormal brake noises that indicate a problem. Check the ABS module or your dashboard for a warning light indicating 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 remains after code clearing, 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 replaced, such as the controller/computer module, wheel speed sensor, and ABS system fuses.