Your car’s Anti-lock Braking System (ABS) is responsible for keeping you safe and in control if an emergency occurs due to heavy braking conditions.
When something goes wrong, the first indication you’ll probably see is the ABS light coming on in your dashboard. That’s a signal to check into what’s going on. Here are some of the most common reasons your ABS light stays on and whether it’s safe to continue driving.
How an ABS System Works
The primary goal of the anti-lock braking system is to avoid accidents and to maintain control of your car in case of emergency braking instead of losing control (skidding).
An ABS safety system can detect a complete stoppage in the motion of the wheels while the vehicle is still in motion (braking) and release brake fluid pressure, which allows the wheels to rotate again.
The ABS is able to do this because it is fully automated. While this may sound basic, the importance lies in controlled stoppage/slowdown of the vehicle while minimizing the chances of losing control of the vehicle.
The ABS allows the wheels of the car to avoid locking up and skidding uncontrolled, all while managing the vehicle’s steering/turning. That being said, a vehicle’s ABS is still serviceable and can fail. If the ABS symbol (light) comes on, the best and safest option is to have the issue resolved as safely as possible.
Common Causes Of ABS Light Coming On
#1. Defective Wheel Speed Sensor
A defective wheel speed sensor is one of many reasons the ABS light comes on and stays on. Wheel speed sensors are located in the center of the wheel, and in some instances, the center of the transmission.
The Anti-lock Braking System uses the information from the wheel speed sensor, as the wheel speed sensors determine the speed the wheels are turning.
The wheel speed sensors will send their information to the ABS. The ABS, upon receiving information from one or more wheel speed sensors, identifies that the wheel is turning at a speed that is slower as compared to the other wheels. The ABS then releases the brake fluid pressure.
This allows the wheel to begin turning again. If you have a problem with the wheel speed sensor itself, whether it is covered in dirt and grime from normal driving conditions or a defective component, then the ABS will not get any information to enable control of the wheels.
The wheel speed sensor is mounted nearly flush against the braking system and is sensitive to any damage caused by extreme heat generated from braking use. A damaged wheel speed sensor could have triggered the ABS light.
#2. Failed Pump or Valve.
When the ABS receives information from the wheel speed sensors, it releases a hydraulic valve to allow increased brake fluid pressure to prevent the wheels from losing contact with the ground.
The valve or the pump is more likely to fail than the wheel speed sensor, and perhaps it has suffered damage through internal wear or even bad brake fluid. Either could turn on the ABS light.
#3. Blown Fuse.
Like almost every system or electrical component, the anti-lock braking system should have a fuse.
Before putting on that expensive part or spending hours diagnosing, make sure the ABS fuse is not blown or burnt out. Checking the fuse is a simple diagnosis that could save you significant time.
#4. Failed ABS Module.
No doubt, another reason for the ABS light to come on would be if the ABS module itself is defective.
The module can show a series of failure codes or operational problems due to corrosion on the communications wire paths, which can cause increased resistance in the communications and therefore either a delay or no communication at all between the wheel speed sensors and the ABS module.
Any amount of corrosion, whether the diameter of a human hair or worse, the ABS module, may not provide operational honesty for diagnostics. The worst-case scenario would be a complete computer change of the ABS module.
#5. Low Brake Fluid.
Like almost every aspect of a brake system, the ABS also requires hydraulic brake fluid to control the pressure.
If the brake fluid reservoir is low, it could cause the ABS to be unable to do its duties, therefore, the ABS light would go on. Also, maybe too much air in the brake fluid system could trigger the ABS light.
Is It Safe To Drive With ABS Light On?
You shouldn’t drive with the ABS warning light illuminated. This means you have a malfunction with an important safety feature.
Your car might not handle when stopping on slippery surfaces like it is designed to during heavy braking, and the odds of having an accident become greater when driving with your ABS light on.
If you have both your ABS light and brake system light illuminated, you should treat this as an emergency and stop driving immediately.