You are sitting in traffic, and you notice the red lights glowing on your instrument cluster.
Shoot… You think to yourself, have I been driving with the emergency brake on the whole time?
You reach for it but notice it’s not engaged. It has to be something to do with the brakes.
In this article, we will discuss 5 common causes of why your ABS light could be on, how the anti-lock brake system works, and finally, how to reset the ABS light (how to turn off the ABS light after repair or get rid of it if it’s on).
How Does an Anti-Lock Braking System (ABS) Work?
In short, it’s an electronically controlled safety measure that keeps you from skidding when you stop in less-than-ideal conditions.
Vehicle brakes are a hydraulic system where when you apply pressure to the pedal, it applies a boosted pressure to the brakes on each wheel.
This, though, is the part when it becomes tricky. Hydraulics, like most things in nature, like to follow the path of least resistance. Additionally, when you brake, the weight of the vehicle moves. Throw in uneven, dirty road surfaces, and you have a recipe for disaster.
Less weight on the wheels means it’s easier for those wheels to stop, i.e., uncontrolled skid. When showing off, skidding is cool, but when trying to stop, not so much.
Image Courtesy of How a car works
It can cause you to lose control as it reduces the vehicle’s directional stability. Thus enters the Antilock Braking System, also known as the ABS system;
Comprising of the:
- ABS pump
- ABS Hydraulic unit and the
- ABS module.
Which is able to regulate the stopping force sent to each wheel.
The ABS system collects information from the wheel speed sensor and hydraulic unit to determine which wheel is about to skid; it, in turn, reduces the force on that wheel and applies it again 100’s of times a second, giving that familiar pedal shudder we all have experienced when you slam on the brakes. ABS brakes don’t necessarily rake faster but do help keep control when braking.
The ABS system detects when something isn’t within the intolerance. Most vehicles have a yellow and a red ABS light.
Yellow ABS lights are generally associated with a car’s electrical system fault.
Red ABS lights usually point to hydraulic-associated faults in the ABS systems.
There is no difference between regular car brakes and anti-lock brakes. The difference is the brain.
What are 5 Common causes for ABS light Being On
Low Brake Fluid
Because the brake system is a hydraulic system, you won’t be able to create enough resistance if the brake fluid is low because it relies on hydraulic pressure.
The ABS module measures the fluid amounts to warn you if it gets too low. A red warning light will often indicate this. Worn brake pads can also decrease the braking fluid level.
Faulty Wheel Speed Sensor
The ABS control module needs constant information from the wheels to know which one is about to skid. The speed sensor (sometimes called the ABS sensor, ABS wheel sensor, or wheel sensor) located on each wheel measures the wheel’s rotation speed.
If it is faulty, it won’t tell the ABS module the wheel’s speed compared to the other wheels.
In turn, the ABS module doesn’t know if it must apply more or less pressure to that specific wheel. This can be the result of damaged wire from the speed sensor. A common tell-tale sign is an inaccurate or erratic speedometer.
This malfunction will activate the ABS light. If you are sure the sensor is working properly, reset the light on the dashboard and inspect the wiring. Potential problems associated with speed sensors are damaged or corroded wires and connections.
Pro tip: A bad wheel bearing, mismatched wheel size, or a severely underinflated tire can cause false readings even on a healthy ABS wheel speed sensor.
Faulty ABS Module
Though they rarely fail, if an ABS computer module fails, you might hear a strange ticking noise or experience erratic braking where you feel no resistance when braking or even feel too much resistance.
This can sometimes be identified with a fault code but often will require that you eliminate all sensors that feed to the module. This will trigger the ABS warning light.
The trouble code should give an indication of which sensor is causing the anti-lock brake light to illuminate.
Modern vehicles utilize an all-in-one design for the module, pump, and hydraulic regulator. This makes it an expensive fix if you replace the whole unit.
Inspect the control module; sometimes, rust or dirt may interfere with communications between it and the entire system.
Worn ABS Pump
The ABS pump(hydraulic pump) is the heart of the anti-locking brake system. And just like a heart, if it’s failing, it’s a serious problem, and the vehicle should not be driven.
A failing pump motor doesn’t effectively pump the brake fluid used to apply the brakes, leading to the inability to stop the vehicle.
A hard or overly soft brake pedal and decreased responsiveness from the brake pedal are all signs of a failing ABS pump motor. This, too, will light the ABS light in red.
Blown fuse
As the ABS module and sensors rely on electricity. A blown fuse can cause the ABS light to come on. Fuses are there to protect the electronics, and a blown ABS fuse can be a sign of a short.
The car owner’s manual or a quick check on Google can point out your car’s specific fuse panel location. The location can be different depending on the location of the driver’s seat.
Inspect the wiring, especially leading to the speed sensors. If not damaged, replace the anti-lock brake fuse using the fuse removal tool supplied. After changing the abs fuse, you must know how to turn off the abs light. If the fuse blows again, have an automotive electronics mechanic inspect the vehicle.
If the dashboard light turns on again, inspect the sensors.
How to clear an ABS light without a scan tool
Please note, the light is there as a warning that something is faulty.
Ignoring and resetting the light does not make this problem disappear and can lead to expensive part repairs and, worse, vehicular accidents. Fault lights should only be reset once you identify and fix the problem.
There are two ways of resetting the light:
The easiest way is with the ignition off, remove the battery terminal cables, starting with the negative battery terminal and the first positive cable.
Using a battery jumper lead, connect the two terminals. Open the driver’s door and turn the ignition on for 20-25 min. The vehicle will not start, but this will drain the remaining power in the electrical system, clearing the light. Reconnect the terminal positive cable first.
The other requires you to jump two ports in the OBD II CONNECTOR. To do this safely, using a fused bridge wire is recommended not to cause damage if you accidentally bridge the incorrect ports.
Using the above methods, the lights should turn off and only return if the fault persists.
Check Out How to do a Quick Reset to your ABS System:
How to reset an ABS light with a scan tool
A scan tool (OBD code reader) is the fastest way to identify and reset the ABS light. You do not need a specific abs scan tool. OBD scanners allow you to access the car’s central computer, where it can find fault codes stored in the system memory.
First, find the OBD II port in your vehicle. (Most vehicles post-1996 have it, and a quick Google will assist you in locating it in your vehicle). Plug in the scan tool and turn the ignition to the second position (The lights on the instrument cluster will be lit up, but the motor will be off.)
Select clear fault codes. Turn off the ignition and unplug the scanner.
And you’re done.
Here is Another Helpful Video:
FAQs
Can the ABS light be reset by disconnecting the battery?
If the car battery is disconnected long enough, it will reset the ABS light.
How Come My ABS Light Won’t Turn Off?
One or more components of the ABS experienced a fault. It can be an intermittent fault, like a voltage drop from a bad battery to an ABS failure. Either way, it won’t go away and must be reset.
How Can You Bleed ABS Hydraulic Units?
You need to squeeze the air out of the system to bleed the hydraulic unit. If you didn’t replace or loosen any hoses at the booster or ABS unit, you would only need to force the air out of the brake line to each brake caliper.
What you will need is the right size spanner for the bleeding nipple. A clear Flexi hose that fits on the nipple located on the caliper and an extra person to depress and hold the brake pedal.
Starting with the rear brakes, have the assistant depress the brake pedal 4-8 times until they feel a bit of resistance. Then, they must hold the pedal down. With the dust cap removed and flexible hose over the nipple, slowly open the bleed nipple for a second. A small amount of liquid and bubbles should come out.
Close the nipple all the while your assistant keeps the pressure on the brake. Repeat until all the bubbles are gone on that caliper.
Check the brake fluid level and repeat on all four calipers.
Pro tip: If you struggle to get the air out of a caliper and the brake fluid isn’t flowing out, use a large syringe to suck the air out on the end of the flexible tube. This process will remove air from the caliper and brake line.
If the air was caught in the ABS hydraulic unit, you will likely need a scan tool to cycle the pump.
Can Autozone read the ABS Codes?
Yes, at Autozone, you can read fault codes free of charge.
Is Driving Possible Without ABS?
Yes, you can drive, but you will need to be cautious.
Because the ABS isn’t working, the wheels lock up when you apply too much brake force. In an emergency situation, you might need to pump the brakes to mimic the function of the ABS and reduce the wheel lock.
Final thoughts
ABS is a vital safety mechanism to keep you safe.
Though you can drive with the anti-lock warning light on, care will be needed if you decide to drive with it inactive. If the warning lights are on and you feel little to no brakes, you must have your brakes checked immediately.
Hopefully, with the help of this article, you will feel confident enough to find, repair, and reset the ABS light.
