How to Check Your Brake System | A Check Brake System Warning Guide

Your car’s brake system is one of the most important parts of your car and means the difference between safely arriving at your destination or getting into an accident. When your check brake system light comes on, it’s an indicator to check this essential system, but how do you go about doing that? 

When the check brake system light is illuminated on your dash, the first thing to check is your brake pads, ensuring they move correctly and replacing them if they are worn. Lubricating parts and checking for wear, damage, and leaks are all checks you should perform before visiting a mechanic.

In this article, we’ll go into detail about the importance of checking your brake system, how to troubleshoot the brake system warning signals, and what to inspect in the event of a brake system warning. Continue reading to learn more. 


What Does the Check Brake System Mean?

The ‘check brake system’ warning message means that your vehicle’s computer has detected an issue with the brake system. This warning message does not specify the issue or how it occurred, giving the driver the responsibility of inspecting and identifying the cause of the message. 

However, there are a couple of problems commonly associated with the check brake system message, such as worn-out brake pads, low brake fluid levels, and faulty sensors.

You need to treat the check brake system indicator as a high-priority issue, as faulty brake systems are one of the leading causes of car accidents on the road.


What Causes the Brake Light on the Dash to Stay On?

Problems with various parts and areas of the vehicle that are involved in the brake system will cause the brake light on the dashboard to remain on. Here are the most common causes:


1. Worn Brake Pads

Brake pads are the parts of disc brakes that are composed of steel backing plates with a material that produces friction. This friction allows your car to stop and is also one of the first things to show signs of wear the more you drive.

Although it would depend on several factors, such as frequency of driving and braking, a good rule of thumb is to check your brake pads every 30,000 km. If your brake pads are around 4-5mm thick, you’ll need to consider replacing them soon, while anything less than 3 mm of thickness calls for an immediate replacement.


2. Burnt Out Brake Globes

Although it might not sound too dangerous to have one or more of your brake bulbs burn out, it indirectly puts you and others in danger since other drivers will not know when you are braking and will be unable to adjust their speed accordingly. 

This is the easiest part of the brake system to check and will not take much time or effort to be replaced, and it is something you can easily do yourself. If you use an older vehicle, you can replace them with LED lights to last much longer. 


3. Faulty Sensors

A common symptom of faulty brake sensors is when you notice the vehicle taking much longer to stop when braking heavily. It could mean that the Anti-Lock Brake System (ABS) wheel speed sensor’s calibration is off and is no longer helping the vehicle come to a full stop in time. If you suspect this to be the case, you must consult the owner’s manual and visit your mechanic for repairs or replacement as soon as possible.


4. Low Brake Fluid Levels

The brake fluid is a kind of hydraulic fluid that transfers force into pressure, effectively bringing a vehicle to a stop when the brakes are pushed in. When your brake fluid levels are too low, air will fill the gaps in your brake line and cause soft brakes. 

Much like the engine, the braking fluid in modern braking systems will have to undergo routine flushes and replenishment. On average, brake fluids must be changed every two years or as the manufacturer or your mechanic recommends.


5. Issues With the Hydraulics

Hydraulics refers to a large portion of the brake system, including brake pads and fluids. However, there are a lot more things that can go wrong with the hydraulics within your vehicle. 

One of the most common issues with the hydraulics system is corrosion — it damages the sealing surfaces of cylinders and causes leakage. A leaking wheel cylinder will allow air to enter the system whenever the brakes are released. The compressible nature of air will result in a “spongy” brake pedal, requiring the brake line to be bled.


6. The Handbrake is Engaged

Although not really a problem, an engaged handbrake can also trigger a check brake system message. In most modern cars, it will be distinguishable as a message saying “Park Brake Engaged”. However, older vehicles do not specify and will just show the usual message. 

Always check your handbrake before moving, as driving with the handbrake engaged will wear down the rear brakes much faster than normal and could eventually lead to a total failure of the brake system.


7. There’s an Issue with the Battery

Not many people know that a low-voltage battery could cause the check brake system message to occur in your car. This is because a battery running low will cause problems with the brake lights, among other internal electrical systems. The vehicle needs a sufficient voltage supply to keep all systems in proper working order. 

You can check this by seeing if any of the vehicle’s lights flicker when idling or are less bright than when the accelerator is revved. Many modern car batteries will also have a visual indicator on the battery itself, helping you determine if it needs to be replaced anytime soon.


Checks to Perform When You See the Check Brake System Error

Listed below are some of the essential checks you need to do If you ever encounter the ‘Check Brake System’ Error or message on your vehicle’s dashboard:

1. Inspect the Tyres

There are many things to check when inspecting the tyres, mainly the tread depth, the tire pressure, and its condition and age.

Here are steps on how to check the tread depth by using the ‘Coin Test’:

  1. Place a 20c coin within the tread of your tyre.
  2. If the tread does not reach the platypus’ bill, your tyres only have less than 3mm of tread remaining, which is below the safe and prescribed level, and would have to be replaced.
  3. You should also check your tyre pressure. Modern vehicles have options to show tyre pressure from the dashboard; you should see if all tyres have equal pressure levels.


If your vehicle does not have tyre pressure sensors, here’s what you can do:

  1. Use a tyre pressure gauge to ensure that they are properly inflated.
  2. Remove the valve stem cap, and press the gauge head onto the valve stem with firm pressure. If you do this correctly, the “hissing” sound should stop.
  3. Remove the gauge and read the pressure. Compare it to your vehicle’s recommended pressure (found in the owner’s manual). 


2. Check the Brake Fluid

To check your vehicle’s brake fluid, you must first locate the brake master cylinder reservoir, which is generally mounted on or close to the firewall at the rear of the engine compartment. This puts it almost directly across the brake pedal mounted on the other side of the bulkhead. The location will always vary across different vehicles, so consult your owner’s manual if necessary. Modern vehicles will have a see-through reservoir with a full line, showing you how much to fill up the reservoir. 

For older vehicles (usually 1980s and older), the metal reservoir will be held on by a spring-loaded clamp and would have to be pried open to one side, then lifted off the top to allow for inspection of the brake fluid. If the brake fluid level is low, add more until it reaches the “full” line. If you’re unsure, you can check your owner’s manual or visit a mechanic. 


3. Test the Suspension

There isn’t just one way to test your vehicle’s suspension; there are several. One way is by visually inspecting the strut mounts:

  1. Open up your vehicle’s hood and look at struts on both sides.
  2. Check for any signs of corrosion or rust on the fasteners that go over.
  3. Check for any loose or damaged fasteners.


Another way of checking the suspension is by measuring the height of your vehicle’s front wheels. You can do this by simply using a tape measure to check the length of empty space from the top of the tyre to the bottom of the fender for both the driver and passenger sides. Any height differences should not be more than 2.5cm.

Lastly, you can also test the suspension by checking the tie rod ends. You can do this by following these steps:

  1. Locate the power steering box and follow the arms that go towards the wheels. If you are having difficulty finding it, consult your owner’s manual.
  2. The tie rod is a suspension component that acts as a connection point between the steering box and the wheels. If any bushings are worn down or damaged, they will need to be replaced.


4. Look for Cracks, Wear or Damage

A broader method of troubleshooting the cause of the check brake system error is by inspecting your vehicle and looking for any sign of cracks, excessive wear or damage. 

Although this may not be as specific as the previous methods, it will give you a general idea of the condition of your car and its systems and allow you to diagnose problems beyond the brake system. This is best done with the guidance of a mechanic so that proper diagnosis and repair can be made.


5. Replace the Brake Pads

As previously mentioned, brake pads will inevitably wear down over time due to usage.

Below are the steps on how to replace brake pads:

  1. First, remove some of the brake fluids from the master cylinder to allow fluid to return to the reservoir once the new brake pads are installed. You can do this by using a syphon.
  2. Raise the vehicle with a high-capacity trolley jack. Place jack stands below the chassis jack stand points and remove the wheel assembly. Consult your owner’s manual for the correct points to jack and place stands if you have doubts or are unsure.
  3. Inspect the brake assembly. Check for signs of grease leaks around the calliper and rotor, and check for signs of cracks or damage on the rotor. Check the brake lines for any sign of leakage or deterioration on the hoses. Any damaged parts found here will also need to be replaced.
  4. Remove the brake pads by loosening the calliper bolts on the top and bottom of the calliper.
  5. Check the bolts, guides, and rubber boots for signs of wear or damage. If the calliper is of the sliding type, make sure it can slide freely on the runners.
  6. In order to fit new pads, you will have to retract the calliper piston back into its housing – you can do this by fitting a block of wood and a ‘C’ or ‘G’ clamp over the piston.
  7. Once you are sure you have the right type of brake pads, install them into the calliper by sliding the calliper assembly back into position and aligning the mounting or locating pins.
  8. Install the ponds or bolts and secure them in place.
  9. Use the correct procedure and “bleed” the brakes (remove the air) and refit the wheels.


6. Test Drive the Vehicle

A more simple way of diagnosing the vehicle is by test-driving it. This is especially effective if you know the ins and outs of your vehicle and you can easily identify what’s wrong just by feeling the driving experience. You can do this to narrow down your list of suspected problems in the vehicle for a closer and more in-depth inspection later on.

Remember to do this in a controlled environment, such as within your neighbourhood or in an empty parking lot, to ensure that you do not cause an accident should something go wrong.


7. Visit a Mechanic

A quick and easy way is to visit a mechanic to have your vehicle checked for any issues that could cause the check brake system error. A professional mechanic will know where to look and what to look for, removing any possibility of user error.

Remember that even with some car experience, taking your car to a licensed mechanic will always be the best option. Not only will they have the experience required to handle whatever issue your car has, but they will have all the best tools and equipment needed to fix the problem.


8. Lubricate Brake Components

Since the brake system involves a lot of moving parts, it must be kept lubricated to a reasonable degree. You can do this by applying the right lubricant onto the brake calliper slides to allow the pad to slide freely. When re-assembling, you can also apply lubricant between the back plate, the calliper fingers, and the calliper bolt.


9. Ensure the Brake Pedal is Moving Smoothly

The brake pedal is the part that you push down on with your foot that triggers the vehicle’s braking system. If this part gets stuck or becomes too hard to push down, it requires immediate attention. If your brake pedal is acting up, call a mechanic to diagnose the problem. If possible, refrain from driving the vehicle until the issue has been solved.


How Often Should Brake Fluid Be Changed?

The general rule of thumb is that the brake fluid should be replaced every two years, depending on the make and model of your vehicle. However, it is recommended that the brake fluids are routinely checked every six months to avoid running into any problems or to diagnose any developing issues early on.


Is It Safe To Drive When The Brake Warning Light Comes On?

No, it is not safe to drive your vehicle if the brake warning light is on because it indicates a serious problem with the braking system and should be given utmost urgency. Driving a vehicle with the brake warning light on will only endanger the driver, its passengers, and other people on the road. 

The ideal way to deal with this situation is to have the vehicle inspected by a professional mechanic and the problems repaired as soon as possible.


What Should I Do If I Have a Brake Warning But I Can’t Drive to a Mechanic?

If you can’t drive to a mechanic and the brake warning light is on, call a mobile mechanic to check on your vehicle from your house or wherever your vehicle is parked. This is ideal if you have roadside assistance, as they’ll be able to reach you in most places around Australia.

The extra costs for roadside assistance are nothing compared to the assured safety of you, your passengers, and other people on the road.


Related Questions

How Long Will Brake Pads Last After the Warning Light Goes On?

Brake pads, on average, will last for around 1,600km after the warning light comes on, depending on the issue with your brake system. To get the 1,600km out of your brakes, you’ll need to brake efficiently on the road, braking with plenty of time, without heavy loads, or on rough terrain. 

Of course, if the brake warning light is on, it’s best to visit a mechanic as soon as possible, as there’s no way of knowing exactly how long your brake pads will last after the warning light appears on your dash.


What Causes Brake System Failure?

There are multiple causes for a brake system failure, ranging from problems in the hydraulics, the braking components, and brake fluids. However, the most common cause of failure is a leak within the brake lines.



Jimmy Mitchell is an electric vehicle aficionado who has been following the space since Tesla first hit the scene. A longtime proponent of sustainable transportation, Jimmy was one of the first to buy a Tesla 3 as soon as it came out. He loves nothing more than helping others learn about and enjoy the benefits of electric vehicles. When he's not evangelizing about EVs, Jimmy enjoys spending time with his family and travelling throughout south east asia

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