Common Causes of ABS Fault and How to Identify Them

The Anti-lock Braking System (ABS) is a crucial modern component of all vehicles. The ABS ensures that, in an emergency manual braking situation, the automobile’s wheels do not lock up. If the system operates correctly, a braking emergency will result in a short period of the wheels locking up, and then releasing for continued braking (known as ‘cycling’), which keeps the driver in control of the vehicle, while reducing the stopping distance. However, any complex system has the potential to throw up errors when things go wrong. A fault with your ABS might show via an illuminating light on the car’s dashboard. Here’s a breakdown of what could be happening if your ABS warning light comes on and what to do about it.

 In this article we’ll offer a diagnosis of the causes for your ABS light failure, along with some tips on how to detect them.

Common Causes of ABS Fault

 Here’s a list of the most common causes of an ABS fault. 1.The circuit in the ABS function.2.The left and right speed signals.3.The input to the ABS module (on older models, there should be a signal on the side of the transmission.4.A bad ground wire.5.A bad module.6.The ABS switch (Normally this gets corroded so badly that it becomes a one-shot system, if it’s a speed-sensitive system).7.The ABS switches that are located on the hubs (Also normally become a one-shot system, from corrosion.8.The pumps themselves.9.The Codes for the ABS system have a tendency to cause problems, leading to an ABS warning on the dash.

Faulty Wheel Speed Sensors

 Wheel speed sensors are one of the first things that measure how fast each of your wheels are turning and send that information to the ABS control module. If this sensor or any of them are to fail, the ABS control module won’t know how fast the wheels are turning, hence the fault. Dirt, road debris and physical damage to the sensors can all be causes of corrupt information.

Damaged ABS Module

 The control module receives the information from the wheel speed sensors and activates ABS when required. If the ABS control module is damaged (by outside water ingress, electrical failure, or wear and tear), the ABS warning light will come on. It may be possible to repair a damaged module, but in other cases, it may need replacing.

Low Brake Fluid Levels

 Brake fluid, of course, is crucial for the effectiveness of brakes, not least but also the ABS. If your brake fluid level is getting low, the ABS might not work correctly. Low brake fluid might be a sign of a (dangerous) leak in your braking system, so you should have it repaired ASAP before you end up with no brakes at all.

Blown Fuse or Electrical Problem

 The ABS has to depend on electronic components to function. If any component of the electrical wiring is not working or a fuse has blown, the ABS will not work and the fault warning light will go on to tell you there is a problem. If you see the dashboard light, check wires and any parts of the electrical system for corrosion or burnout.

Worn Brake Pads or Rotors

 Although brake pads and rotors are not a component of the ABS system, worn-out brakes can impact the way your ABS system operates. If your brakes are no longer in good shape, the ABS might be triggered more often or when it shouldn’t and components within the ABS system will wear out prematurely, which can cause an ABS malfunction. 

Hydraulic Pump Issues

 The ABS system utilises a hydraulic pump to replenish the pressure in the brake lines after the ABS reduces this pressure. If the pump fails, the system can’t maintain the correct amount of hydraulic pressure, resulting in failure.

How to Identify ABS Faults

 It is unlikely that you can pinpoint every ABS fault without specialist help, but there are several things you can try: 1. Does ABS work as normal or does it fail? If it fails: 2. Get to the dealer as fast as you can.

ABS Warning Light

 The yellow or amber dashboard warning light obvious indication of an ABS fault. On being switched on, this warning light means only that there system. It will stay on as a warning, so you shouldn’t ignore it.

Use an OBD-II Scanner

 An OBD-II scanner can read the fault codes for various ABS faults Many writers about ABS will tell you: a scanner (a device that plugs into your car’s onboard diagnostics [OBD-II] system) can read the fault codes for various ABS faults. We’ll start with what the codes mean. A faultcode will point to the root problem (sometimes literally, as in ‘sensor A is out of range’). A code will point to a related problem (for instance, ‘sensor B isn’t re-uenrolling because of a problem further up the chain’).

Check Brake Fluid Levels

 Another super-quick check is to check that your brake fluid is up to the minimum – this can be the cause of your ABS fault symptom. Make sure that you’re filling the system with the right kind of brake fluid for your vehicle, and if you get the level up but it goes low again very quickly, root out any possible leaks.

Inspect Wheel Speed Sensors

 If you’re able and willing to work underneath your vehicle, you can identify and check the wheel speed sensors visually. These sensors are normally mounted close to the brake discs (rotors) and sometimes collect debris or dirt in the surrounding area, which alters the wheel speed sensor’s DC reference voltage. In this case, you can simply clean and potentially replace damaged sensors to solve an ABS problem.

Listen for Unusual Noises

 Occasionally, an ABS issue shows itself through sudden odd noises in the brake pedal, like clicking or grinding noises, that can indicate that the system’s hydraulic pump is failing or its other components are worn out.

Check for Braking Issues

 While the ABS fault light can come on before the vehicle’s actual braking ability is compromised, telltale differences in the vehicle’s braking performance will start to become noticeable when the system is malfunctioning. You could notice longer stopping distances or a pulsing sensation in the brake pedal, for example.

What to Do When You Have an ABS Fault

 And if it’s a fault with your ABS, it’s something you should have rectified as quickly as possible. Here’s what to do.

Address Minor Issues Yourself

 Now, some low-level ABS faults – such as low brake fluid, dirty sensors or a defined amount of friction-materials – are quite solvable by the home mechanic. With the proper tools and the right knowhow, you could be your own ABS diagnoser. 

Seek Professional Help for Complex Issues

 More serious problems, such as a corroded ABS module or a faulty hydraulic pump, should be addressed by a professional. Repair or replacement of these components by a trained technician is vital to the safety of your vehicle. 

Don’t Ignore the ABS Warning Light

 As enticing as it may be to ignore the ABS warning lamp if your vehicle’s braking feels normal, you might put yourself at risk – an ABS fault can reduce your ability to stop your vehicle, especially under emergency braking or in poor conditions.