How to Fix the ABS Light on a Car

The ABS light came up in your instrument cluster? Don’t worry! The ABS light only means there’s a problem with your vehicle’s antilock braking system and that it has been deactivated. And while driving without ABS might be a concern in the long run, your braking system isn’t compromised and should still be working normally. At this point, all you need is to fix the issue, and the warning light should disappear by itself.

ABS stands for Antilock Braking System, a feature preventing your wheels from locking up under hard braking. It’s a modern car brake system introduced in the 1950s but only became mandatory for all cars sold in the EU in 2004 and the US in 2012.

Thus, every vehicle sold in Europe and North America today (along with most countries globally) has built-in ABS. Still, several older car models are also equipped with one, particularly premium models from the 80s and 90s. For instance, my fourth-gen 5 Series has ABS — unfortunately, while very helpful, it can malfunction occasionally. And since shops are quite costly nowadays, I fixed the issue by following a trusty BMW repair manual.

Indeed, once you have a repair manual and the manufacturer’s recommended troubleshooting and replacement procedure to rely on, you’ll see that ABS system issues are generally not that hard to fix. Although that really depends. On a BMW like mine, the issue is often caused by a faulty speed sensor — an affordable component that takes an hour to replace once you get the hang of it. But in other vehicles, the culprit for an ABS brake problem might be something else completely. Nonetheless, you don’t have to worry, as I’ll list every part that might be linked to the antilock braking system light turning on.

So, if you’re curious about how to fix an ABS light on a car, keep reading. I’ll dive deep into the problems that trigger the antilock light on, how to identify them, and how to fix them.

Let’s go!

ABS Light On: Nothing Urgent, But It’s Best To Fix It Right Away

Here’s how the ABS works in a gist:

Whenever you’re braking hard, the wheel sensors send signals to the car’s ECU (engine control unit), letting it know of any potential wheel lockup. The ECU then commands the ABS module to reduce/increases the pressure inside the braking system multiple times per second, preventing the wheels from locking up.

You’d probably be fine without ABS under normal driving conditions. And even with the ABS light on (so ABS being deactivated), you’ll be able to drive as usual. Your brakes will still work fine without the anti-lock feature, though emergency braking won’t be as safe, as you might lose control of your vehicle more easily. No need to mention that ABS is undoubtedly crucial in winter, or on any slippery surface for that matter, helping you remain in control throughout emergency braking situations.

And of course, like any safety feature, you’ll never know when you need it, but you’ll certainly be glad you have it when you do (remember airbags? lol). Hence if you find your ABS light stays on, it’s best to be safe and fix it sooner. Who knows, it could save you from future close calls and accidents.

What Makes the ABS Light Turn On

The antilock braking system light can be triggered by anything going wrong in your car brake system. But since the antilock light problem is nothing out of the ordinary, especially on older vehicles, we are now familiar with the most common culprits, which I’ve summarized below.

Faulty ABS Module

Every ABS-equipped vehicle has a control module (ABS module), which is essentially the brain of the entire system. Although it rarely fails, it might need repair when it does.

A faulty ABS module is commonly associated with corroded wires, causing a delay or complete cut-off in communication between the wheel speed sensor and the ABS module. If you’re lucky, you can restore it with some simple rewiring. Otherwise, you’ll need to replace the whole module, which is the safest but also the most expensive alternative.

Aside from a glowing ABS light, other signs of a bad ABS module may include an unresponsive brake pedal, increased pedal effort, and wheels locking up under heavy braking.

Low Brake Fluid

The brake fluid is crucial for the proper functioning of the ABS. Without sufficient fluid, the ABS module may struggle to balance the brake pressure on each wheel when needed, basically nullifying the system. Hence whenever the brake fluid level is low, the ABS light may come on to warn you that the system has been deactivated as a preventive measure.

Low brake fluid may occur due to worn/damaged brake lines, worn brake pads, or a leak within the system (located anywhere within the brake lines, hoses, calipers, or master cylinder). Symptoms of a low brake fluid include a smushy or completely unresponsive brake pedal — which is never good.

Faulty hydraulic unit

The ABS pump distributes the brake fluid needed by the system to control the brake pressure. If the hydraulic pump fails, there won’t be any brake fluid reaching the brakes, leading to poor braking performance or even a complete car brake system failure.

Unfortunately, the brake pump is commonly subject to wear and tear, especially since it’s often exposed to outside elements. As a result, it’s best to check it regularly and replace a faulty pump as soon as possible before it can cause any harm on the road.

Faulty Speed Sensor

The wheel speed sensors read the actual speed of the wheels and report it back to the ECU and ABS module, which use this information to detect any speed difference between each wheel and apply the brakes to keep them even. So when an antilock braking system sensor fails, it could disable the entire system (including other ABS-reliant systems like traction control, stability control, etc.) since there is no speed data to process.

The common cause of a faulty speed sensor may include corrosion, excessive bearing end play, and road debris or brake metal shavings blocking the antilock braking system sensors. You’ll most likely need to replace it since a faulty speed sensor is rarely repairable.

Blown Fuse

Like any other car electronic system, the ABS source its power through a fuse protecting the circuit from shorts and other electrical malfunctions. While a blown ABS fuse indicates it has successfully safeguarded the module and the related components, it also means it needs to be replaced and that whatever caused the fuse to blow in the first place will need to be repaired — simply replacing the fuse without fixing the problem first will simply cause the new fuse to blow right away too.

You can tell a fuse is blown by its dark and cloudy appearance or by testing it using a multimeter or a test light. Once you’ve found the cause of the problem and repaired it, simply replace the fuse with a new one of the same amperage, and the ABS light should go off on its own.

Bulb Check Error

Most vehicles do a bulb check at start-up, lighting up all instrument cluster lights for a few seconds. So there’s a slight chance of it glitching, leaving the ABS light on for no reason. If that’s the case, a simple restart should usually solve the problem, but it wouldn’t hurt to take it for a code reading to ensure there’s no intermittent ABS error.

How To Fix ABS Light on a Car

There’s no other way to get rid of the ABS warning light but to fix what’s causing the issue. However, with so many possible causes, you could’ve to undergo a rather long and painful troubleshooting process before finding the culprit. Therefore, I recommend using a scan tool or OBD code reader to check for ABS codes first. If a DTC code was recorded, it will tell precisely what triggered the ABS light. Once you’ve pulled the code, you’ll be able to find the related troubleshooting procedure in your car’s repair manual.

Once you’re there, all you need to do is follow the manufacturer’s instructions, and you’ll eventually find where the problem hides.

How To Service Antilock Brake System

Of course, besides fixing it when it breaks, you can do a few things to ensure your ABS system works properly for a longer period. First, don’t miss out on your brake inspection. Many ABS brake problems are due to faulty brake components that are avoidable with a bit of preventive maintenance every once in a while.

Thus, frequently check the lines and hoses for leaks, and follow your car’s maintenance schedule to know when to change the brake pads and fluid. Furthermore, avoid frequent late braking that activates the ABS. Not only is it rather dangerous, but overusing your ABS wears the brake components faster. Instead, drive safely and step on the brakes sooner and smoother.

Last Words

I know many people turn a blind eye to the antilock light since it doesn’t prevent them from running daily errands. Nonetheless, an ABS brake problem could lead to severe accidents — there is a reason why it’s mandatory in new vehicles today.

Without an ABS system, your vehicle will be much trickier to handle when braking on wet pavement, snow, and ice. And if you ask me, safety should always be your utmost priority when driving, no?

Thus, learning how to fix the ABS light on a car is crucial to keep you safe, but also other traffic participants. Luckily, issues with the ABS car brake system are usually easy to fix, with cheap and readily available parts. There is really no justification for keeping the antilock braking system light shining in your instrument cluster any longer.