Product Technology

ABS Light On? It’s Not Always a Big Deal

Posted on by Daisy
23
Jun

Have you ever had this happen?

You’re driving along when suddenly the ABS warning light pops up on your dashboard. Your heart skips a beat—”Is something wrong with the brakes?”

Don’t panic! ABS light on ≠ ABS failure.

The real reason might be much simpler than you think.

Let’s break down this commonly misunderstood warning light and what it’s trying to tell you.

What Is the ABS Warning Light?

ABS stands for Anti-lock Braking System, a safety feature that prevents the wheels from locking up during hard braking, helping you maintain steering control in emergencies. When the ABS warning light comes on, it means the system has detected an issue with one of its components. But don’t jump to conclusions — it doesn’t necessarily mean the entire ABS has failed. In many cases, it may be a minor issue, such as a faulty sensor or a wiring glitch.

However, when the ABS light is on, it does indicate a malfunction in the anti-lock braking system. This could result in the wheels locking up during sudden braking, making it harder to slow down or steer the vehicle safely, which is a potential safety risk. There are different ways the ABS light may appear (solid, flashing, or intermittent), and each type of warning may point to a different cause and solution.

Common Reasons Why the ABS Light Comes On — And How to Fix It

  • Low brake fluid level is one of the most common reasons for the ABS warning light to come on. Brake fluid is essential for transferring braking force and also plays a key role in the ABS. When the fluid level is too low, the ABS may not function properly, triggering the warning light.

Solution: If you notice the brake fluid is low, top it up to the recommended level immediately. After refilling, restart the vehicle and take a short drive to see if the ABS light turns off. If the light remains on, further inspection is required.

  • The wheel speed sensor is a critical component of the ABS, responsible for detecting the rotation speed of each wheel. A malfunctioning sensor or damaged wiring can cause the ABS to stop working properly and trigger the warning light.
    Dirt buildup is the leading cause of ABS sensor failure, accounting for around 40% of everyday ABS issues. Mud, metal shavings, and road grime can contaminate the sensors mounted near the wheels, distorting their signals due to constant exposure to the elements.

Solution: Use a non-metallic tool to adjust the gap between the sensor and the tone ring to approximately 0.51 mm (0.02 inches). If the ABS light remains on, use professional diagnostic equipment to check the resistance of the sensor. If the resistance reading falls outside the acceptable range of 800–1200 ohms, you should replace the sensor.

Note:

  1. A faulty front wheel sensor may cause one side of the vehicle to experience brake lock-up.
  2. A rear wheel sensor issue often results in delayed ABS engagement during braking
  • On older vehicles, it’s common for the ABS warning light to come on after driving over rough roads or bumps. This often results from loose connectors or blown fuses, especially in vehicles over 5 years old or frequently driven on uneven terrain.

Solution: Focus on checking these two key areas:

1. Wheel Speed Sensor Connectors:

Inspect the sensor plug—pay attention to worn or brittle clips when disconnecting.

Use an electronic contact cleaner to remove any oxidation buildup on the terminals.

2. Fuse Box:

Locate the fuse labeled ABS (typically 15A–30A).

Continuity test and replace it with a fuse of the same rating if necessary.

Pro Tip:

On German vehicles, ABS wiring near the engine bay may become brittle due to prolonged heat exposure.

Moisture often enters near the wheel well on Japanese cars, causing short circuits that lead to ABS connector issues.

  • Worn brake discs or pads can also trigger the ABS warning light. Excessively worn brake discs or pads reduce braking performance, causing the ABS to detect an abnormal condition and activate the warning light.

Solution: If the brake discs or pads are found to be excessively worn, it is recommended to replace them promptly to restore normal braking performance. It’s advisable to have a professional technician perform the replacement.

  • A malfunctioning ABS control module can also cause the ABS warning light to illuminate. The ABS module is the central component of the system, responsible for receiving signals from sensors and managing brake force distribution based on driving conditions. If the ABS light remains on and is accompanied by unusual brake pedal behavior (such as a soft pedal or absence of the usual system self-check noise), it may indicate a failure in the control module or hydraulic pump.

Solution: If you’ve ruled out other potential issues, a faulty ABS control unit likely caused the problem. In this case, take the vehicle to a professional repair shop for a thorough inspection and repair. Common steps include:

    1. Using an OBD diagnostic scanner to retrieve specific fault codes (e.g., C0110 indicating pump motor circuit malfunction).
    2. Checking the brake fluid for moisture content (if it exceeds 3%, a full replacement is required).
    3. Reprogramming the ABS control unit using specialized equipment (typically available at authorized service centers or dealerships).

⚠️ Warning: Do not attempt to disassemble the ABS pump yourself. Improper handling can introduce air into the brake fluid lines, leading to serious safety hazards.

Can you keep driving when the ABS light comes on? Is it dangerous?

If your ABS warning light comes on while driving, there’s no need to panic—but it should not be ignored either. In most cases, you can continue driving, as your regular braking system will still function. However, the ABS (Anti-lock Braking System) itself will be disabled, which means your wheels may lock up during hard braking.

Without ABS, sudden braking can cause the wheels to skid or lock, reducing your ability to steer and increasing the risk of losing control, especially on wet or slippery roads. So while the car remains drivable, it’s important to drive with extra caution.

Avoid sudden stops, maintain a safe following distance, and reduce your speed as needed. Plan your route and give yourself more time and space to react to traffic conditions. Although your vehicle can still brake normally, the absence of ABS support significantly reduces your safety in emergencies. If the light stays on, have your ABS checked and repaired as soon as possible.

Emergency Handling Steps for Drivers When the ABS Warning Light Appears

If the ABS warning light comes on, follow these step-by-step measures based on the severity of the situation:

  • Basic Response:

Restart the vehicle to check if the issue is intermittent → Check the brake fluid level (it should be between the MIN and MAX marks) → Clean any visible ABS sensor around the inner side of the wheel hub.

  • Advanced Checks:

Measure the car battery voltage (if it’s below 11V, recharge it) → Visually inspect ABS wiring for any signs of wear, damage, or disconnection.

  • Immediate Repair Required:

If the ABS warning light appears along with the handbrake light, you feel a pulsating sensation in the brake pedal during braking, or the dashboard displays messages like “ABS INOP,” these signs indicate serious issues. Take the vehicle to a repair shop immediately.

Conclusion: The Ultimate Reminder for Safe Driving

While around 80% of ABS issues can be resolved through basic troubleshooting, a failed ABS can increase braking distance on wet or slippery roads by more than 1.5 times. To ensure your safety, drivers are strongly advised to:

  • Clean the ABS sensor magnetic heads every 2 years
  • Check the ABS pump seals whenever brake fluid is replaced
  • After long-term parking, perform an ABS self-check when starting the vehicle (the ABS light should turn on for about 3 seconds and then go off — this is normal)

Remember: A constantly illuminated ABS warning light is not just a symbol — it’s a safety alert. Addressing it promptly can make all the difference in an emergency stop and protect lives.

Related blog: Brake System Cleaning: Don’t Overlook the “Grime” in Your Brake Fluid Lines

Daisy

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