Subaru Legacy ABS Light On

Subaru Legacy ABS Light On: Causes and How to Reset It

No doubt, the Subaru Legacy is a conventional and reliable vehicle known for its safety features. One of these features is the Anti-Lock Braking System (ABS), which helps prevent your wheel from locking up during braking. However, there are instances when the ABS light illuminates the dashboard, indicating a potential issue with the system.

So, what are the causes of the Subaru Legacy ABS light coming on? 

  • Faulty wheel speed sensors
  • Corroded ground
  • ABS pump and module issues
  • Brake system malfunction
  • Low brake fluid level
  • Worn-out brake pads or rotors.

In this piece, we will explore the causes behind the activation of the ABS light in a Subaru Legacy and discuss how to reset it.

Common Causes of ABS Light Activation

As we mentioned earlier, if the ABS light comes on, it indicates that there is a problem with the Anti-Lock Brake System. This is caused by several malfunctions and problems. Here are some possible causes:

Common Causes of ABS Light Activation

Faulty Wheel Speed or ABS Sensors

One of the common causes of the ABS light turning on in a Subaru Legacy is a faulty wheel speed or ABS sensor. The wheel speed or ABS sensor is in charge of monitoring the speed at which each wheel rotates. 

Also, they detect if your car wheels are getting locked up because of hard braking. Therefore, If the sensor fails, your ABS module will stop receiving this data, and it can trigger the ABS light to activate.

Subaru Legacy Faulty Wheel Speed or ABS Sensors

How to repair it? 

To repair a faulty wheel speed sensor in a Subaru Legacy, follow these steps below: 

  • Step 1: Diagnose with an OBDII scanner to read the fault codes and determine if the wheel speed sensor is the cause of the problem.
  • Step 2: Locate the sensor by removing the wheel and brake assembly to access it. 
  • Step 3: Remove the old sensor, which is held in one place by a clip or bolt. Remove the clip or bolt and gently pull out the sensor from the hub. Be careful so you don’t damage the hub.
  • Step 4: Install the new sensor into the hub and secure it with the clip or bolt. 
  • Step 5: Reinstall the wheel and brake assembly and torque the lug nuts to the manufacturer’s specifications.
  • Step 6: Clear every ABS code or any (Diagnostic trouble codes) DTCs using a code reader or a scan tool.
  • Steel 7: Test the ABS to ensure it is properly functioning by test-running your car to be sure the ABS light isn’t coming on again.

The cost of replacing a wheel speed sensor in a Subaru Legacy can range from $330 to $380, and labor from $80 to $100. The parts are from $265 upwards. 

Corroded Ground

A corroded ground is a connection point between the electrical system and the car’s chassis that has become corroded after some time. This can happen because of exposure to dirt, water, and other pollutants. 

Corrosion on your ground connection can cause electrical resistance, which can lead to a variety of problems. Also, it can cause the ABS sensor to malfunction, leading to an incorrect signal being sent to the ABS controller. Thereby resulting in the illumination of the ABS light.

Subaru Legacy Corroded Ground

How to repair it?

Here are some steps to fix corroded ground in your Subaru Legacy car:

  • Step 1: Disconnect the negative battery terminal first before you disconnect the positive one.
  • Step 2: Locate the ground connection near the battery or on your vehicle’s chassis. 
  • Step 3: Clean the ground connection using sandpaper or a file to remove any corrosion or rust. 
  • Step 4: Apply a protective coating such as dielectric grease or battery terminal protector to prevent future corrosion
  • Step 5: Reconnect the positive battery terminal first before reconnecting the negative terminal.  
  • Step 6: Test the system to ensure the ABS light is no longer illuminating.
Read:  Dodge Ram 2500 ABS Warning Light On: Reasons and Resetting Tips

ABS Pump and Module Issues

The ABS pump and module are integral components of the ABS. The ABS pump restores lost pressure to the hydraulic brakes after the hydraulic valves have released it. 

While the ABS module is the controller of the whole ABS. Issues with these components, such as a malfunctioning pump motor or a defective or leaking module, can lead to the ABS light coming on. 

Subaru Legacy ABS Pump and Module Issues


Replace the ABS pump with a new one, and it is recommended to take your car to a trusted professional auto mechanic to fix this. Also, the same goes for a defective or leaking ABS module. Have the module replaced at an auto mechanic repair shop.

The cost of replacing the ABS module and pump is around $1,174 and $1,301, including parts and labor costs.

Brake System Malfunction

A malfunction within your brake system, such as a failing brake master cylinder or a leaking brake line, can cause the ABS light to illuminate. The ABS relies on the proper functioning of the overall brake system, so any issues can trigger the warning light.

Subaru Legacy Brake System Malfunction


The first step is to diagnose the problem with your brake system. Take your vehicle to a trusted auto repair shop to have the brake system checked and determine the extent of any problems.

Here are the steps to diagnose a brake system malfunction in a Subaru Legacy:

  • Step 1- Listen for unusual sounds: If you hear any squeaking, grinding, or other unusual sounds when you apply the brakes, this shows a problem with the brake system. This could be due to worn brake pads or grooves in the brake rotors.
  • Step 2- Check the brake pedal: If the brake pedal feels spongy or goes to the floor, it may indicate a problem with the brake system. This could be due to low brake fluid, air in the brake lines, or a faulty master cylinder.
  • Step 3- Check for leaks: Look for any signs of leaks in the brake lines, calipers, or wheel cylinders. Leaks can cause a loss of brake fluid, which can affect the performance of the brake system.
  • Step 4- Test the parking brake: Test the parking brake to ensure it is working properly. If it is not holding the vehicle, it indicates a problem with the brake system.

To solve the problems, take the steps accordingly-

  • Remove air from the brake line, and top up the brake fluid to get to the middle of the “Min” and “Max” lines in the reservoir. Also, replace the faulty master cylinder and replace faulty brake pads and rotors as well.
  • Fix the leaks in the brake lines and wheel cylinder. Also, replace the faulty calipers if needed. 
  • If the parking brake has issues, have it fixed by a professional auto mechanic. 
  • Other fixings can range from the replacement of the brake pad to a complete brake job.

Note that the cost of repair is determined by the problem diagnosed. 

How to Reset the ABS Light in a Subaru Legacy?

After fixing the underlying issues, the ABS light should go off automatically. If the light remains, then you can follow the following methods to reset the ABS light in your Subaru Legacy. 

How to Reset the ABS Light in a Subaru Legacy

Method 1: Using an OBD-II Scanner

An OBD-II scanner is a diagnostic tool that can communicate with the vehicle’s onboard computer system. By connecting the scanner to the OBD-II port, you can retrieve and clear any stored ABS error codes, effectively resetting the ABS light. 

Read:  Ford Focus ABS Light On: Causes and Resetting Tips

Method 2: Disconnecting the Battery

Disconnecting the vehicle’s battery for a few minutes can sometimes reset the ABS light. Start by disconnecting the negative terminal of your battery first before you disconnect the positive battery terminal.

Method 3: Disconnect and reconnect the ABS fuse 

To reset the ABS in a Subaru Legacy, follow these steps:

  • Step 1: Turn off the ignition
  • Step 2: Locate the ABS fuse. It is found in the fuse box under the hood or in the interior fuse box. Step 3: Remove the ABS fuse with a fuse puller or with a needle-nose kind of player.
  • Step 4: Leave the ABS fuse out of its slot for at least 5 minutes to allow the ABS to fully reset.
  • Step 5: Reinstall the ABS fuse: 
  • Step 6: Start the engine and check if the ABS light is still illuminated.
The Subaru Legacy is a renowned model, but like all vehicles, it’s not immune to issues like the ABS light coming on. However, the Legacy isn’t the only Subaru model with this concern. Those who own or are interested in the Subaru Impreza might want to read up on common causes and fixes for the Impreza’s ABS light issues. Similarly, another popular Subaru model, the Outback, has had its share of ABS light challenges. Our comprehensive guide on why the Subaru Outback ABS warning light might be on can provide insights into the potential problems and their solutions.


Below are questions people also ask about Subaru Legacy ABS light illumination and the answers provided to them. 

Q: Can ABS affect the gearbox?

Yes, bad wheel speed sensors or ABS can affect the gearbox and the vehicle’s transmission entirely.

Q: Which fuse controls the ABS?

The ABS functions with electricity. A relay and an anti-lock fuse control it. The first fuse is 10 amp, while the second fuse is 30 amp. 

Q: Does the ABS sensor affect driving?

No. A faulty ABS sensor won’t affect driving.  But it’s not the best idea to drive a car with a bad sensor because it can affect the entire functionality of ABS.  Therefore, fix your ABS sensor once it’s bad to maintain the stability and proper function of your car. 


Hopefully, you now know what causes your Subaru Legacy’s ABS lights to come on and how to fix them. We also provided methods for resetting the ABS light. Once you notice the ABS light illuminating your Subaru Legacy dashboard, it is important not to ignore it. 

The ABS is designed to enhance your vehicle’s safety, and any issues should be addressed promptly. Follow the appropriate steps for resolution to ensure the proper functioning of the ABS in your Subaru Legacy to maintain optimal safety on the road.

Also, if you aren’t comfortable with fixing the issues yourself, I suggest keeping your Subaru Legacy to a professional auto mechanic for efficient solutions. 

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