The antilock braking system (ABS) light is an important safety feature in modern vehicles. It prevents the wheels from locking up and skidding when braking on slick roads.
What causes this light to come on and what can you do to clear it? Can you drive with the ABS light on? This guide will help you answer these questions and more.
What Does the ABS Light Mean?
If you’ve ever driven a vehicle without ABS and locked up the wheels while trying to stop on an icy road, you may have noticed the car sliding straight ahead even when the wheels are turned. As mentioned, ABS prevents the wheels from fully locking up, helping you maintain control of the vehicle even when hard braking at highway speeds.
And since ABS is an electronic system, it also has a warning light to alert you of any issues.
The ABS light on your vehicle’s dashboard typically glows amber, orange, or red and displays the letters “A-B-S.” If this light is on, it indicates a problem with your ABS or traction control system (TCS), or it could mean that your ABS has completely stopped working.
Additionally, the ABS can activate the red BRAKE light on your dashboard, which also serves other functions unrelated to the ABS.
What Causes the ABS Light to Come On?
The ABS has several components that can fail and cause the warning light to illuminate. The ABS light may come on if there are issues with the ABS module, wheel speed sensor, fuse, or hydraulic control unit, or if you have low brake fluid.
Here’s more information on each possible cause:
Broken ABS Module
A broken ABS module will cause the ABS light to illuminate, but don’t go buying a replacement module just yet because it’s more likely to be a wheel speed sensor. If the ABS module connector’s pins are corroded or damaged, the module can’t receive the wheel speed data from the sensors and won’t be able to deliver output commands to the solenoids in the Hydraulic Control Unit (HCU).
If there’s an issue with the ABS module, you may notice reduced brake pedal responsiveness, a check engine light, or a clicking or cracking sound while braking. In some cases, the brakes may lock up while driving. However, a rapidly bouncing brake pedal during a panic stop is a normal function of the ABS.
Low Brake Fluid
Some braking systems use hydraulics to operate. When the brake fluid is low, the red BRAKE light will come on, along with the ABS light in most cases. If the red BRAKE light comes on at first and then turns off when you’ve driven a mile or two, you’ll likely find low fluid due to disc pad wear and more fluid being stored in the calipers. This is normal as the brakes wear.
Malfunctioning Wheel Speed Sensor
Antilock braking systems use analog or digital wheel speed sensors to determine how fast each wheel is going and if there is a need to lessen pressure on the locking wheels.
If the wheel speed sensor is malfunctioning, it can limit the transmission of important data to the ABS.
Faulty Hydraulic Control Unit
Your vehicle’s hydraulic brake control unit or pump can wear out over time due to dirt or debris in the brake fluid. If these components don’t work properly, the ABS is impacted as well. This can trigger the ABS warning light.
Signs of this issue include spongy brakes, brake fluid leaks, brakes that won’t release after a hard stop, and reduced or inconsistent brake performance.
Blown Fuse
The ABS and its components have their own fuses, which can blow. If this happens, both the ABS and check engine lights will illuminate. A quick inspection of the ABS fuse can confirm if this is the issue. However, if the fuse is blown, there may be a short circuit causing it, so be prepared for the fuse to blow again almost right away.
How to Clear the ABS Light
The ABS light typically switches on for 2 to 4 seconds at startup as the system checks for issues. If the light remains on beyond that timeframe, what should you do?
If you’re driving, carefully pull over to the side of the road and avoid braking aggressively. Turn off the engine for a few minutes, then restart it to allow your vehicle’s computer to re-check all systems. If the light persists, visit the nearest auto repair shop for a diagnosis and to address the underlying issue.
Another way to clear the ABS light is by using a scan tool that retrieves ABS codes. Standard OBD2 scanners won’t do this, but more advanced tools will, and they plug into the same DLC connector used for engine codes. Good scan tools will also let you monitor wheel speeds while the vehicle is moving, which is very helpful for ABS diagnostics.
FAQ
Can you drive with the ABS light on?
You can drive with the ABS light on because the brakes will still function. However, it’s not advisable, as your tires may seize up if you brake too hard or drive in certain weather conditions. This limits your vehicle’s maneuverability in emergencies and can endanger you and your passengers. While your normal brakes will still work, an issue with the Hydraulic Control Unit (HCU) could affect them, as the brake lines pass through it on the way to the wheels.
Will a car pass inspection with the ABS light on?
A vehicle with the ABS light illuminated will not fail an inspection. However, it will be marked “danger” in the report. To be safe, clear the ABS light and address the root cause before having your vehicle inspected.
Can a low battery cause the ABS light to come on?
Yes, a low battery can trigger the ABS light to come on because the module is programmed to detect low system voltage. It can also cause the PCM to register trouble codes as well. If your ABS light is on, make sure your car battery is in good shape before doing anything drastic.