Brake Servo Restricted alert

Brake Servo Restricted [Meaning, Causes & Fix]

Many Audi and VW owners have reported seeing a “brake servo restricted” error message on the dashboard when driving. Sometimes the message is accompanied by another saying “You can continue driving your car.”

This can be a worrying error message, especially since it is alerting you to a potential issue with your brake system. So what does the brake servo restricted error message mean?

In this article, I will be answering this question, telling you the possible causes of the message and what you can do to fix the situation. Lets get to it.

Brake Servo Restricted Error Message Meaning

To fully understand what the error message means, we need first to know what the brake servo is and what it does.

The brake servo or brake booster is a device found in a car’s braking system that helps in braking by boosting the force applied by the driver on the brake pedal.

By increasing the force, the brake servo contributes to more responsive and efficient braking.

Now, if there is an error in the normal functioning of the brake servo, your car’s system detects the malfunction and alerts you to it with the brake servo restricted error message so you can take the necessary action.

Note that a faulty brake servo can potentially lead to more serious damage to other components of the braking system, such as the Anti-lock Brake System (ABS).

Ignoring the warning over a long period can also lead to potential braking system concerns when driving. It is, therefore, important to have your car checked and fixed if you experience the brake servo restricted error message.

What Causes the “Brake Servo Restricted” Alert?

So what exactly causes the brake servo restricted warning message on your Volkswagen/Audi dashboard? Here are a few common causes:

A Faulty Brake Servo Pressure Sensor

The most common cause of the error message is a damaged or faulty brake servo pressure sensor. This sensor monitors the pressure in your vehicle’s braking system.

It sends signals to the system so that the brake servo adjusts the pressure appropriately and provides the braking assistance required.

If the pressure sensor is faulty or gets damaged, it is not going to monitor the pressure in your braking system accurately or it can delay sending signals, leading to problems in your braking system.

Many Audi and Vw drivers have reported feeling the brakes becoming a little stiff when the message appears. Some have also reported having to apply more force when braking when the error message pops up.

This tells you the importance of having a well-functioning brake servo.

Potential Software Problems

Another possible cause of the issue is software errors. Most, if not all, of the modern vehicles on the roads today rely on electronic control systems.

If there are software errors in the electronic control units that control the braking system, particularly the brake servo, there can be miscommunication between the servo and other parts of the braking system, leading to a brake servo warning message.

Brake Master Cylinder Problems

When you apply force on the brake pedal, the master cylinder converts the force into hydraulic pressure, which activates the brakes.

If you have a faulty master cylinder, one of the potential problems you will encounter is decreased hydraulic pressure. This decreased pressure may affect the operation of the brake servo, resulting in a warning message on your dashboard.

Vacuum System

Leaks Most of the brake boosters use the vacuum pressure that the engine intake manifold supplies. Therefore, if there happen to be any leaks in the vacuum system, there is a high chance that the brake servo will malfunction.

The leaks may occur at various parts such as at fittings, hoses, or even at the brake servo itself. Note that vacuum leaks can lead to other issues, so if the error message is due to a leak, you want to have your car fixed as soon as possible.

How to Fix Brake Servo Restricted Error Message

The brake servo restricted error is a problem you need to take seriously and it requires a systematic approach. It is always advisable to take it to your Audi/Volkswagen Service Centre so it can be properly diagnosed and fixed.

That said, here are a few fixes to the brake servo restricted error: 

1. Replace the Brake Servo Pressure Sensor:

If you suspect the issue may be the pressure sensor (it is most of the time), you need to get a replacement with the same sensor. You should get help from a certified technician. 

2. Repair All Vacuum System Leaks:

Again, you want to make sure your Audi has zero vacuum system leaks. It is important to get help from a professional so your car can be inspected properly. 

3. Have the Brake Master Cylinder Checked:

This is another possible fix. If you have tried the above two fixes and the issue is still on, get a technician to check the master cylinder for any issues. 

4. Update Your Car’s Software:

You should also try updating all the system software related to the brake system. Outdated software can cause the brake servo restricted error message, so be sure to have regular updates.

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