/ / / ABS Light on Freightliner: 2 Reasons Behind On ABS Light Discussed

ABS Light on Freightliner: 2 Reasons Behind On ABS Light Discussed

If the ABS Light on Freightliner it demands your attention. This warning light indicates something is not suitable with the Anti-lock Braking System.

In this article, we will delve into the causes of the lights coming on in the Freightliner, solutions to reset, and important steps to take for maintaining your truck’s safety. So buckle up, DIYer, and get ready to learn how to keep your Freightliner safe on the road!

ABS System Function in Freightliner Trucks

The ABS system in Freightliner trucks is designed to maintain optimal braking performance by preventing wheel lockup during sudden or hard braking. It does this by continuously monitoring wheel speed and adjusting brake pressure accordingly. This helps in the following:

ABS Light on Freightliner
  • Maintain traction
  • Improve vehicle control
  • Reduce skidding or sliding risks

What Causes the Light to Come On

There are several reasons why this light may come on. Each can have severe consequences for the safety of the driver and passengers.

What Causes the ABS Light on

The main cause behind this warning light include:

  • Defective speed sensors
  • A faulty module
  • Low fluid levels
  • A failing brakes booster.

1. Insufficient Fluid in the Reservoir

Each system has its reservoir, plumbing, and brake chamber. If you’re experiencing low fluid in the reservoir on your Freightliner, there are a few potential causes to consider:

  • Fluid leak: The hydraulic fluid in the reservoir plays a crucial role in transmitting the pressure from the brake pedals to the wheel brakes. Check for any visible signs of fluid dripping or pooling under your Freightliner wheels.
  • Faulty fluid sensors: A Freightliner vehicle often comes equipped with liquid-level sensors that monitor the fluids. If it is malfunctioning or giving the wrong readings, it may indicate low fluid levels when they are normal.
  • Improper fluid filling: If the fluid reservoir was recently refilled or topped up, it might not have been done appropriately. Fluid levels in Freightliner vehicles are typically specified in the owner’s manual or on the reservoir itself.

2. Wheel Speed Sensor Issues

Wheel speed sensors (WSS) provide essential traction and stability control systems information. Some vehicles even compare the WSS readings against the vehicle speed sensors (VSS) to ensure all of these sensors are accurate and working correctly.

Wheel speed sensors (WSS) provide essential traction and stability control systems information


Common symptoms of faulty speed sensors on Freightliner trucks are;

  • A TCS warning light on the dashboard
  • Erratic or inconsistent TCS behavior
  • Loss of traction control
  • A malfunctioning speedometer.


Some of the primary causes of these issues can include:

  • Sensors damage or failure due to dirt, debris, or corrosion
  • Corroded or damaged wires or connectors
  • Internal faults or electronic issues.
Solution and Repair

Depending on the severity of the problem, potential repairs may involve;

  • Cleaning the sensors and their surroundings
  • Repairing or replacing damaged wiring or connectors
  • Replacing the WSS
  • Reprogramming or recalibrating the system

Reset ABS Light

To reset ABS light, park your Freightliner if you are on the road. Grab a scanner to aid in the diagnosis of the problem. It should display codes similar to those found in the truck manual.

Reset ABS Light

1. Utilizing Jumper Cables

Using jumper cables to restart the electrical circuit is one way to reset it. To do that, follow these steps:

  • Ensure you have DLC jumper cables or an adapter kit for the service.
  • Turn the truck off and connect the wires.
  • There blinking now.

By following the proper steps and utilizing jumper cables, it is possible to reset the electrical circuit and get a blinking signal indicating success.

2. Applying the Brakes

Follow the next steps carefully after using your jumper cables. If you do not, there could be more issues.

  1. Depress the brake pedal, do not be rough, and do not touch the gearbox and the accelerator.
  2. After it clicks, push it down eight times within a few seconds.
  3. The lights should not be off.

Following the recommended steps after using jumper cables is important to avoid any potential issues.

3. Repeating Steps

Once it switches off, the light is now reset. Some freight liners will have the light stay on for a few seconds and blink four times.

If you notice the abs light staying on, don’t panic:

  • Pull over
  • Wait at least a minute
  • Try again

Watch this video: for a visual guide.

ABS Light Blinking? Here’s What to Do in a Few Simple Steps

If the light flashes, it signifies that you need to reset it. To do so, there are steps that you need to adhere to to prevent any additional problems. It’s crucial to follow these steps carefully in the correct order.

If the ABS light is flashing, it means you need to reset it
  • Press the brake pedal gently without engaging the accelerator or gearbox. The DCL connections should make an audible clicking noise.
  • Once you hear the noise, press and release the brakes eight more times, this needs to be done quickly. Don’t wait in between each press. The whole process should only take seconds.
  • Sometimes, a few seconds may pass before it blinks four times. Once the reset process is finished, they should switch off.
  • If it doesn’t turn off at this point, you might have pushed on the brakes for too long or not done the entire procedure quickly. If this occurs, completely let go of the brake pedal, turn off the engine before starting it, and then repeat the process.
  • Your car should be ready to go after removing the cables. If it isn’t and the light is still on, an expert in the trucking industry must look into the issue.

Freightliner Chassis: Troubleshooting Tips

The ABS lights on the Freightliner chassis may sometimes come on for various reasons such as:

While this is a valuable safety feature, its absence doesn't mean the brakes won't work
  • A speed sensor issue or a temporary setting-related trigger: In some cases, driving the unit at a higher speed, typically above 25-30 mph for a mile, may help reset ABS light. This could be due to moisture or corrosion clearing up while in motion.
  • A broken or corroded wire in the wheel speed sensor may require repair: It is advisable to contact Freightliner Customer Service, which is available 24/7 for guidance and potential solutions in the trucking industry.

Note: It is important to note that while this is a valuable safety feature, lacking it does not mean the brakes won’t work. However, without it, the driver is solely responsible for managing any possible skids or control problems when braking.

Important! If you experience an intermittent flash on your Freightliner chassis, it is essential to address the issue promptly and not ignore it. While it may clear up after driving, it is crucial to pull aside, identify and resolve the underlying cause to ensure the safe operation of your vehicle.


Can you Drive with the ABS Light on?

Driving with the ABS light on is not recommended, especially if it’s blinking. The system may not function properly, compromising the truck’s braking performance and safety.

How do I Reset my Freightliner ABS?

You can try resetting your Freightliner using jumper cables or pressing the brakes. However, It is advised to call a qualified technician to help identify and fix the underlying issue if the problem continues.

What Does ABS Mean on a Freightliner?

It stands for Anti-lock Braking System, a safety feature in trucks.

Why is my Semi-truck ABS Light on?

The ABS light on your semi-truck may come on for various reasons, including low fluid in the reservoir, speed sensor issues, wiring problems, faulty sensors, or other equipment-related problems.

What Causes an ABS Fault?

The fault in your Freightliner can be caused by several factors, for example, shortage of fluid in the reservoir, faulty wheel speed sensors, faulty wires, or defective module. A qualified technician’s proper diagnosis is essential for identifying the specific cause and performing necessary repairs.


The ABS light on a Freightliner is a crucial warning signal for potential issues with the Anti-lock Braking System. Addressing this warning promptly and conducting regular maintenance are essential steps to ensure the safety and proper functioning of the vehicle.

We’d like to hear from you: Have you ever experienced an ABS light issue with your Freightliner truck? Share your story in the comments below!

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