Service Brake Assist: Meaning, Causes, and How To Fix

Automobile manufacturers are consistently improving the safety features of their vehicles by introducing a range of innovations. Among these advancements is the brake assist function. When the brake assist doesn’t work efficiently, a Service Brake Assist message might start to illuminate on your dashboard.

The primary purpose of the brake assist system is to improve the performance of regular braking, especially during sudden and critical conditions. By enabling swifter stops when drivers encounter braking complications, this mechanism is meticulously crafted to avert an accident.

Furthermore, this technology supplements the force applied to the brake pedal, thereby assisting in halting the vehicle, achieved through the utilization of hydraulic valves, a pump, and an electric motor.

However, a malfunction in this system may activate the service brake assist warning light on the vehicle’s dashboard. This article explains the service brake assist message causes and how to turn it off.

What Does Service Brake Assist Message Mean?

The Service Brake Assist message indicates that there is something wrong with your Brake Assist system. This could stem from a brake sensor malfunction or insufficient pressure within the braking system. In both scenarios, immediate attention is advisable.

Service Brake Assist

The Brake Assist system of your car constantly measures the pressure exerted on the brake pedal. In critical situations demanding heightened pressure, this classy system steps in to provide the extra force required.

Function of Brake Assist

The Brake Assist system of a vehicle gauges the level of pressure exerted on the brake pedal, guaranteeing its adequacy for averting collisions in sudden stops or emergency situations.

Brake Assist

When this system identifies the need for a rapid stop but observes that the brake pedal hasn’t been completely pressed, it introduces supplementary hydraulic pressure. This additional pressure reduces the stopping distance until your car comes to a complete stop. This capability of the Brake Assist system holds immeasurable value in preventing potential accidents.

How Brake Assist Works

Brake Assist Working

Brake assist operates by closely observing the driver’s regular driving patterns, particularly their brake application habits. It interferes by supplying additional braking power when its sensors detect a quick and forceful engagement of the brake pedal.

In essence, this system is engineered to provide a safety net in situations where emergency braking occurs without an optimal driver response. It corresponds to its function with the ABS system to ensure the brakes are appropriately activated during urgent circumstances.

The brake assist system of your vehicle owns a distinctive programming capability that allows it to learn your braking behavior. Consequently, if any deviation from the norm is detected, the system responds by delivering increased power to guarantee effective braking and lower the overall braking distance.

Is Brake Assist The Same As ABS?

Brake assist and ABS are distinct yet complementary systems that collaborate to achieve optimal braking efficiency. The brake assist function increases the brake pedal’s force, allowing it to engage quickly during emergencies.

In contrast, the anti-lock braking system (ABS) focuses on preserving the traction of your vehicle’s tires while decelerating. This empowers the driver to maintain steering control effectively.

The ABS system of a vehicle mainly stops unexpected wheel lock-ups, ensuring that steering remains responsive as the vehicle slows down. Consequently, while interconnected in their operations, the anti-lock braking system and brake assist system serve as separate systems that collectively enhance the safety of driving.

Brake Assist VS Automatic Emergency Braking

Automatic Emergency Braking and Brake Assist systems might seem similar, but they work differently. Brake Assist helps by adding more brake power when you press the pedal but not hard enough. It gives you an extra boost.

In contrast, the Automatic Emergency Braking system operates independently of your actions. When the sensors detect a hazardous situation, and you fail to apply brakes despite warnings, the vehicle autonomously engages the brakes. This self-sufficient technology takes over the braking process. It’s usually a part of safety packages in vehicles or can be added as an optional feature.

Causes of the Service Brake Assist Message

A faulty brake light switch or brake pressure sensor is one of the most common causes of the service brake assist message, especially when you notice this message without an ABS light or other warning lights.

Nevertheless, this warning may also be caused because of many other reasons. Therefore, it is essential to perform a thorough diagnosis for an accurate understanding.

The following are the most common reasons for the service brake assist message:

1) Low Brake Fluid Levels

Brake Fluid Level, causes of Service Brake Assist message

The service brake assist light will illuminate if your brake fluid is low. It may also be caused if any component within the braking system becomes faulty.

When the brake fluid is inadequate, the ABS valve’s operation can be affected, reducing brake efficiency. Insufficient fluid levels might also cause a soft and spongy pedal feel, impacting driver confidence and prolonging stopping distances.

2) Bad Brake Assist Pump

Modern cars contain an electric pump that helps to generate brake pressure. When this pump becomes faulty, it may cause the activation of the service brake assist message.

3) Worn Brake Pads

Worn Brake Pads

A faulty brake pad is also one of the major causes of the service bake assist message. The brake pad is one of the most crucial components of the braking system.

It may gradually wear down over time. This deterioration may diminish the performance of your braking system, posing risks to you and other drivers on the road.

4) Wheel Speed Sensors

ABS Wheel Speed Sensor Location

The ABS system of a vehicle depends on the ABS wheel speed sensor’s data to check if any of the wheels are locking up while braking. An issue with the ABS sensor may cause wrong information delivery to the ABS and trigger the service brake assist message.

Read More: Bad Wheel Speed Sensor Symptoms

5) Bad Brake Booster

The master cylinder, housing a piston connected to a flexible tube, collaborates with the brake booster of your vehicle. When the driver presses the brake pedal, the piston resists the pushback from the flexible tube, making extra pressure on the brakes.

The engine’s intake manifold generates a vacuum that draws air into the engine, moving the piston. If there’s no vacuum or insufficient vacuum, your car’s ABS system quickly activates to compensate for the reduced power.

6) Vacuum Leaks

Vacuum Leak

Vacuum boosters can cease functioning due to a vacuum leak. A vacuum leak can hinder your car’s ABS performance, complicating driving conditions.

This can escalate to loss of vehicle control or even accidents. Leaks in the brake booster can also trigger overheating issues and failures of other components, like master cylinder pistons and wheel cylinders.

Read More: Vacuum Leak Symptoms and Causes

7) Brake Pedal Position Sensor

Accelerator Pedal Position Sensor

The brake pedal position sensor constantly monitors the position of the brake pedal. When this sensor stops working efficiently, it may badly impact the performance of your brake assist system.

Read More: Bad Accelerator Pedal Sensor Symptoms and Causes

8) Damaged Wiring

Corrosion can cause damage to wiring harnesses in the electrical system if moisture infiltrates. This corrosion may render wires brittle or loose, potentially compromising the proper functioning of your vehicle’s brake system.

How To Fix the Service Brake Assist?

Follow the following steps to reset or fix the service brake assist:

1) Reset the Light

There is a slim chance the service brake assist light came on accidentally. While unlikely, it’s wise to rule out this possibility before proceeding. Resetting the brake assist light is a way to confirm the presence of an actual issue.

The most effective method involves using an OBD-II scan tool. If this tool isn’t accessible, an alternative is to disconnect the power supply.

Park the vehicle in a safe location, turn off the engine, and disconnect the negative battery terminal. Inside the vehicle, press the brake pedal to remove any remaining power. Once done, connect the negative terminal of the battery and turn on the ignition. At this point, the light should go away.

Perform a test drive to check if the light reappears. If it reappears, it’s time to move forward with the next steps.

2) Read the Trouble Codes

When addressing issues in modern cars, it’s advisable to utilize an OBD-II scanner to simplify the diagnostic process. You can opt to purchase an OBD-II scanner for personal use, although specific compatibility might be necessary with your car model and its brake assist system.

Begin by reading the trouble codes and proceed with troubleshooting based on the data gathered.

3) Check for Vacuum Leaks

The brake booster of your car relies on a vacuum to function efficiently. Typically, a hose connects the brake booster to the engine intake manifold to supply this vacuum.

A check valve is in place to retain the vacuum within the brake booster during driving.

If a vacuum leak occurs anywhere or the check valve is damaged, brake pressure can decrease, and the service brake assist system warning might appear. In the case of a diesel engine, a bad vacuum pump could also be a contributing factor.

4) Check the Brake Pressure Sensor

A faulty brake pressure sensor may also lead to the failure of the brake assist system. When this sensor becomes faulty, the entire system could be affected.

To resolve this issue, you need to change the faulty sensor. The placement of this sensor varies, typically found on the ABS unit or the master brake cylinder, contingent upon your vehicle’s model.

The replacement part’s cost may range between $15 and $160. If you’re able to install the sensor independently, there won’t be any additional expenses. Even if professional assistance is required for sensor installation, the cost could range from $70 to $220.

5) Check Brake Fluid Color and Level

Color of Brake Fluid

The brake system of relies on hydraulic fluid, known as brake fluid, to generate pressure. This fluid is essential as you press the brake pedal and is actively used by the brake assist system. A low fluid level could result in inadequate brake pedal pressure, potentially affecting your ability to stop promptly.

It’s a good idea to take a moment and assess the brake fluid color and level. Checking is straightforward; clear indicators on the dipstick cap or reservoir will help you determine if more fluid is required.

If your fluid appears dirty, it is advisable to flush your brake fluid and add fresh fluid. A mechanic can do this for about $100. It’s usually suggested to do this maintenance every two years or after driving about 30,000 miles, whichever happens first.

Read More: How To Check Brake Fluid Level and Color?

6) Replace Bad ABS Parts

When the service brake assist warning light appears alongside the traction control light or ABS light, the issue might pertain to the ABS module rather than the brake assist system.

The primary culprits within the ABS system that may potentially affect brake assist are a problematic ABS pump, a faulty ABS ring, or a malfunctioning ABS sensor.

7) Inspect Brake Boosters

The brake booster serves as the mechanism for increasing the power transmitted from the pedal to the master cylinder of the brake system. It’s what makes a power-assisted brake system different from a manual one.

When the brake booster malfunctions, you might receive a Service Brake Assist message.

If you want to replace the brake booster, the part could cost you anywhere from $80 to $520. Opting for professional help could add around $120 to $460 in labor charges. Keep in mind that these figures are rough estimates; the final cost will depend on your car’s make, year, and model.

8) Contact A Professional

If none of the above-given methods is helpful, it’s advisable to consult a professional. Given the intricate nature of advanced technologies like the Brake Assist system, pinpointing the exact problem can be challenging.

FAQ Section

Why does the ABS light come on?

During instances of the ABS helping in steering your vehicle on slippery surfaces, the anti-lock braking system warning light might light up for a short time. But if the ABS light persists or starts flashing irregularly, it’s indicating a problem with the system that requires your attention.

What is the function of Brake Assist?

Brake assist is engineered to enhance regular braking performance, particularly during emergencies. It’s not intended to replace the driver’s standard braking action; rather, its purpose is to amplify braking efficiency by applying additional pressure when necessary.

Is it possible to drive without brake assist?

Yes, driving without the brake assist system is possible, but you’ll need to apply considerably more force to bring the vehicle to a complete stop. Even if the boosting effect is lost, a mechanical link still exists within the booster. Additionally, it’s feasible to modify a car’s brake system to eliminate the booster altogether.

How much does it cost to fix the service brake assist?

The average replacement cost of a brake booster falls within the range of $630 to $790. Within this, parts usually account for around $430 to $550, while labor expenses can vary from $200 to $240. This estimate doesn’t encompass taxes or other potential expenses, and it doesn’t consider the specific vehicle or regional pricing disparities. There might be additional repairs required as well.

Is ABS the same as brake assist?

No, ABS and brake assist are not the same. Rather than replacing the anti-skid capabilities of ABS, brake assist is designed to complement it. During abrupt stops, ABS rapidly pumps the brakes to prevent the car from sliding or skidding. Without this function, the brakes could lock up, leading to a loss of control and potential veering off the road.

Can Brake Assist Be Turned Off?

Certain models offer the option to deactivate safety features, although having a button for this purpose is uncommon. To determine the capabilities specific to your vehicle, it’s best to consult your owner’s manual. It’s important to note that deactivating these systems means you won’t benefit from their protection during that period.

At what speed does brake assist start working?

Certain Autonomous Emergency Braking (AEB) systems are restricted to city speeds of 55 mph or lower. Meanwhile, other AEB systems remain operational at highway speeds, which typically exceed 55 mph.

Can I drive with the Service Brake Assist Warning?

Generally, driving with illuminated warning lights on the dashboard is inadvisable. However, the Service Brake Assist light should be of particular concern. A malfunction in this system poses a significant danger.
With compromised control over the braking mechanism, the risk of collisions and accidents increases. When this warning light activates, it’s recommended to pull over at a safe location. You should promptly address the issue by seeking professional assistance.

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