What does ABS stand for?

You probably know the Check Engine light means something is up with your vehicle’s engine. A light illuminating the dash could mean you need an oil change or even a new engine. An ABS light is different because it only relates to your braking system. This could be a simple fix or a complex issue. What does ABS mean? How does the ABS system work? Here’s what to know.

What does ABS mean?

ABS is an acronym for anti-lock braking system, an anti-skid sub-component of the braking system. As the name suggests, it means the brakes do not “lock up” no matter how hard you step on the brake pedal.

An ABS car works much the same way as a non-ABS car, only with the addition of a few components such as wheel sensors and an ABS controller. This system uses wheel speed sensors to “see” when the wheels are about to lock up while the car is moving. The controller sends a signal to release some brake fluid and pulse the pressure going to the pad, letting the brake rotor slip and the tire regain grip.

This happens 20 times per second, preventing a dangerous loss of traction. The result is reduced braking distances and the ability to steer during the even hardest braking. The downside is when something goes wrong, you’ll be introduced to the ABS light.

What does the ABS light mean?

An illuminated ABS light doesn’t mean your brakes aren’t functioning. Instead, it is an indicator that some part of the ABS system has an issue and might not be working properly. Just as you can run the engine with the Check Engine light on, you can still drive and brake with the ABS light on. It just means your vehicle’s brakes might be operating as non-ABS brakes.

You might notice the ABS light illuminates right when you step on the brake. This is because the ABS system usually only monitors for wheel slip when the brakes are activated. A brake pedal switch is an open circuit until you press the brake pedal. This closes the circuit, illuminating the brake lights and powering the ABS relay to take readings from the wheel sensors.

The ABS system has a self-test that performs a function check at every start-up. Like the rest of your instrument cluster lights that go out after a few seconds, the ABS light turns off when everything checks out as good to go. If the light stays on, some part of the ABS system has failed or has a communication error, and you’ll see an ABS light.

Reasons for the ABS light

Let’s look at what could have gone wrong in your vehicle. It’s usually one of a handful of causes.

Damaged/disabled wheel speed sensor

Vehicle speed sensors use a rotating reductor wheel and fixed magnet to generate a signal to send to the ABS module so it can calculate wheel speed in relation to vehicle speed. Both are tough components, but they can fail. A damaged or disconnected sensor will let you know through the ABS light.

Bad ABS module

An ABS module is the microprocessor or computer behind the ABS programming. Just as the engine has a computer in the electronic control unit, the ABS system has one with the ABS module. This system receives input from wheel sensors and processes data to make decisions on which brakes to operate. It also stores malfunction codes and other information and sends output signals to the solenoid valves that modulate the pressure on the braking components. The output signal from the ABS module is also what ends up physically activating the ABS light.

Blown fuse

Hopefully this is your issue because it’s an easy diagnosis and fuses are cheap to replace. A blown fuse creates an open circuit that disables ABS components because they don’t receive power. Before swapping out difficult to reach components, look at the fuses. ABS fuses are often in the vehicle’s main fuse panel.

Low ABS fluid

The ABS system relies on the proper amount of brake fluid in the system in order to work. The control of that fluid is the basis for how ABS, as well as the rest of the braking system, works. Low brake fluid can cause an ABS light, but you’ll probably notice other symptoms, such as a soft, spongy-feeling brake pedal.

Broken wires

Every vehicle will start to wear out as the years and miles add up, and that includes electrical components. Wires can take damage from fender benders and road debris, rodents and improper repairs or just corroding and oxidizing. Broken wiring interrupts the signal between the wheel sensor and the ABS controller, and that missing information is enough to send up the ABS light.

Traction control problems

The stability control, or traction control system, uses the same wheel speed sensors and other ABS components to perform its safety monitoring and tasks. A failed traction control module will likely cause an ABS light because failures in the associated components disable the ABS system.

What to do if your ABS light comes on

Keep in mind, the yellow ABS light comes on or flashes during ABS operation, so if you intermittently see it during hard braking, odds are the system is fine. But let’s say your ABS light is on steadily and you think it’s a malfunction. There are some steps you can take to get the underlying issue resolved. Get your vehicle to the dealership or your local mechanic as soon as possible. ABS is a handy safety feature, so you don’t want to drive without it for too long. If it’s a long way until payday, you can still drive your vehicle with an ABS light illuminated but keep your distance from other vehicles and brake early. A disabled ABS also can interfere with stability (traction) control, so hit up your mechanic as soon as you can.

  

Nelson Xavier Ssenyange

Team Leader

Germax Autos, Spares & Garage Ltd

Lukade Road, Naalya

0779250886/0752088734