Subaru Impreza ABS Light On: Common Causes and Resetting Options

Illuminating the Anti-Lock Braking System (ABS) in the Subaru Impreza indicates underlying issues. To fix the issues, you must learn the causes and take the fixing steps accordingly. 

So why is my Subaru Impreza ABS light coming? The reasons behind the issue are as follows. 

• Faulty Wheel Speed Sensors
• ABS Control Module Malfunction
• Faulty ABS Rings
• Low Brake Fluid Level
• Blown fuses related to the ABS system. 

In this blog post, we will explore the common causes behind the ABS light coming on and the available options for resetting it. 

Common Causes For Subaru Impreza ABS Light-On and Fixes

Several factors can trigger the ABS warning light in your Subaru Impreza, and they include:

Faulty Wheel Speed Sensors

The ABS system relies on wheel speed sensors to monitor the rotational speed of each wheel. These sensors are typically mounted near the wheel hub or axle and generate electrical signals based on the wheel’s revolutions. 

Faulty signals mislead the module, affecting braking response by engaging unnecessarily or not when required.

Faulty ABS sensors can trigger unnecessary system engagement, causing brake pedal pulsation or loss of brake pressure. The ABS warning light signals potential problems to the driver.

 Several factors can lead to the malfunction of wheel speed sensors:

• Physical Damage to the sensor from debris, rocks, or even accidents.
• Corrosion and rust buildup around the sensors
• Sensor contamination
• Sensor Aging
• Loose wire

How to Fix a Faulty Wheel Speed Sensor?

Here are guidelines on how to fix a faulty wheel speed sensor.

• Diagnose the issue in the sensors in which wheel it happens. Check for physical damage or wire disconnection. 
• Remove the old wheel speed sensor.
• Install the new wheel speed sensor.
• Test drive the vehicle.

ABS Control Module Malfunction

This module is responsible for processing data from the wheel speed sensors and determining when to engage the ABS system. It contains various electrical components and circuits. 

A malfunctioning control module results in the ABS light coming on. The module’s proper functioning is disrupted by issues such as

• Damaged wires, loose connections, or blown fuses
• Moisture or water intrusion
• Electrical spikes or voltage surges
• Wear and tear over time
• Software or Firmware Errors.

How to Fix an ABS Control Module Malfunction?

Here are the steps to fix an ABS control module malfunction 

• Clean the debris from the wheel and the sensor.
• Disconnect the positive cable from the car battery.
• Employing an OBDII scanner to detect and clear the issues.
• Replace the ABS control module. 

Low Brake Fluid Level

Brake fluid ensures safe brake operation, transmitting pedal pressure to wheels. Low fluid in the Subaru Impreza affects ABS, risking longer stops accidents. As a safety measure, the ABS light will illuminate to alert you to stop and examine your car promptly. 

Solution for Low Brake Fluid Level

If the ABS light comes on in your Subaru Impreza due to low brake fluid, it is crucial to take immediate action:

#1. Inspect for Leaks: Low brake fluid can be a result of leakage in your braking system. Inspect the brake lines, calipers, and wheel cylinders for any signs of fluid leakage, and have any issues repaired by a qualified mechanic.

#2. Correct The Brake Fluid Level: Open the hood and locate the brake fluid reservoir. Ensure the fluid level is between the “MIN” and “MAX” marks. When it’s low, add  DOT 3 brake fluid, which is the recommended brake fluid type, to bring it to the proper level.

Faulty ABS Rings 

ABS sensor rings, or tone rings, on Subaru Impreza wheels, work with speed sensors for ABS data. Rotating, the ABS sensor ring’s teeth pass speed sensors, generating impulses to monitor wheel rotation for independent ABS control.

It reduces the braking system’s performance on slippery roads and produces unusual noise while braking. However, the ABS rings can become faulty for the following reasons:

• Damage from Road Debris
• Wear and Tear
• Corrosion

Solution

Replace the damaged, worn-out, or corroded ABS ring. Here is a general guide on how to replace a broken ABS ring on a Subaru Impreza:

• Identify the broken ABS ring.
• Remove the wheel.
• Lift the Subaru Impreza off the ground.
• Secure it with jack stands.
• Loosen the lug nuts.
• Remove the bolts securing the brake caliper.
• Accessing the ABS Ring.
• Install the New ABS Ring.
• Place the wheel back onto the wheel hub.
• Lower the Subaru Impreza to the ground.

Blown ABS Fuses Related To The ABS System

ABS fuses protect electrical components, including the ABS system, from electrical overloads and potential damage. ABS fuses act as safety measures to prevent excessive current flow that could harm the ABS. 

When a circuit experiences an overload or a short circuit, the ABS fuse will blow, interrupting the current and safeguarding the components from damage. This can be a result of:

• Short circuits or wiring issues
• Component Failures
• Water intrusion or exposure to moisture

To determine if a fuse has blown, examine its appearance for signs of darkness or cloudiness. Alternatively, you can employ either a multimeter or a test light to test the fuse.

Solution

A blown ABS fuse should be replaced with a new one. To replace a blown ABS fuse in a Subaru Impreza, you can follow these steps:

• Locate the fuse box. It is under the hood. Identify the blown fuse by identifying the fuse labeled ABS.
• Replace the blown fuse with a new one that has the same amp rating as the blown fuse and insert it into the empty socket. Push the fuse firmly into place until it is secure.

Resetting Options For The ABS Light In A Subaru Impreza

After fixing the underlying issues that bring the Subaru Impreza ABS light on, the light should go off automatically. But, sometimes, the light may persist, and you have to reset the ABS light manually. 

Here are the methods to follow to reset your Subaru Impreza ABS light after fixing the issues. 

1st Technique: Using an OBD-II Scanner

The use of an OBD-II scanner is essential as a diagnostic tool that communicates with the car’s onboard computer to read and clear fault codes. To check and erase ABS codes on a Subaru vehicle, you need to do as follows. 

• Locate the diagnostic connector and pins, which are located underneath the steering wheel.
• Insert a diagnostic pin into location number six of the diagnostic connector.
• Turn the key to the ignition on position, and the ABS light will start flashing. The first digit is represented by a long flash, and the second digit is represented by a short flash.
• Write down the codes that are flashed.
• To erase the codes, remove the pin from pin location 6 within 12 seconds, holding it in for at least 0.2 seconds each time.
• Verify that the codes have been cleared by cycling the ignition and checking for the absence of any fault codes, except for code 11.
• Turn the key to the off position, remove the pin from the diagnostic connector, and bundle the connectors back up. 

2nd technique: Disconnect the Battery

If you don’t have an OBD-II scanner, you can try disconnecting the car’s battery to reset the ABS light. Here are the steps to take:

• Turn off the ignition and remove the key.
• Locate the negative terminal of the battery (marked with a “-” sign).
• Disconnect the negative cable from the battery and wait for about 10-25 minutes.
• Reconnect the negative cable to the battery terminal and tighten the nut securely.
• Turn on the ignition to the “ON” position without starting the engine to check if the ABS is still illuminating. At this point, if it is still illuminating, then proceed to fix the underlying issues.

If the ABS light persists even after addressing the underlying issues, seek the expertise of a qualified mechanic or a Subaru dealership. They will conduct a thorough inspection of the ABS system and diagnose any potential problems that may require repair or replacement.

When it comes to the Subaru Impreza, one of the common challenges faced by owners is the ABS light illuminating. But it’s worth noting that the Impreza isn’t alone in this. If you’re a Subaru enthusiast or planning on getting another model, you might find our guide on the Subaru Outback ABS warning light quite enlightening. On the other hand, if you’re considering a switch from Subaru or just want more general knowledge on the topic, our detailed breakdown of issues leading to the Ford Explorer’s ABS light activation can be a handy resource.

FAQs

Here are some questions people also ask about why their Subaru Impreza ABS light is illuminating, and answer them. 

Final Words

If you encounter the ABS light illuminated on your Subaru Impreza’s dashboard, it’s crucial not to ignore it. Address the underlying cause promptly to aid the proper functioning of the ABS. Remember that the ABS plays a vital role in enhancing vehicle safety during braking, and keeping it in top condition is paramount. 

If you’ve resolved the issue causing the ABS light to come on, you can attempt to reset it using various methods. This includes manual driving, using an OBD-II scanner, or disconnecting the battery. However, when in doubt, always seek assistance from a professional mechanic or dealership to correctly diagnose and fix the ABS-related problems.