Brake system warning light: Everything you need to know

When your brake system warning light appears, this usually means that your brakes are in use.

However, if this dashboard warning light (typically orange or red) persists when the brakes aren’t being used, this warrants investigation. Numerous issues can trigger the brake system warning light. So, it’s best to have a mechanic diagnose any braking faults.

In this guide, we’ll help you identify the brake system warning light, highlight its common triggers, and the action required when it appears. We’ll also cover the different variations of this light, including what they mean, and what could happen if you leave them unchecked.

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What is the brake system warning light?

The brake system warning light symbol is usually a small circle, surrounded by brackets, with an exclamation mark in the middle.

The appearance of the light may differ slightly in some vehicles. Sometimes, the word ‘brake’ may appear next to the symbol.

It’s important to note that the brake system warning light indicates that something within your braking system is not working as it should be.

Common reasons for the brake system warning light to illuminate

Low brake fluid

Brake fluid is used when your brake pedal is engaged. Pressurised fluid from the brake hoses and brake lines causes the piston in the callipers to place pressure on the inner brake pads. This then squeezes the brake pads, enabling you to slow down. So, if your brake fluid is running low, it will need to be topped up.
Worn brake pads

If your brake pads are worn, this may trigger the brake system warning light. However, it’s important to note that some cars have an entirely separate dashboard warning light for worn brake pads. This resembles a circle with three rounded dashes on the outside of the circle.
Failing hydraulic brake circuits

When the hydraulic brake circuits fail, this may also trigger the brake system warning light.
Faulty sensor

A sensor fault may trigger the brake system warning light. This can also indicate that the anti-lock braking system (ABS) has malfunctioned.

What to do when the brake system warning light comes on

Check your brake fluid levels
- Before you can check your brake fluid levels, you’ll need to locate the master cylinder, sometimes referred to as the brake fluid reservoir. This is usually a white or yellow plastic cylinder - and can be found on the driver’s side.
- Next, you need to check the fluid level. To do this, you should look for the minimum and maximum markings, found on the reservoir. This will indicate the optimal range of fluid.
- If you can see that the fluid is too low, you’ll have to flush your brake fluid before adding any more.
- Once this is done, fill your fluid up to the maximum line.
Inspect for leaks
- To inspect for leaks, park in a safe place.
- Then, push your brake pedal down. If it sinks slowly to the floor, this could be indicative of a leak.
- Next, check under and around your car for any yellowish fluid pooled on the ground.
- If you see liquid on the floor, this means there has been a leak, and you should not drive any further.
- If you’ve found a leak, call your local garage for recovery.
Check the parking brake
- Check to see if your handbrake is fully released.
- If it is not, simply pull the handbrake up to release it fully.
- If the brake system warning light stays illuminated once the parking brake has been released, take your car to a mechanic as soon as possible.
Test braking performance
- To test your car’s braking performance, press the brake pedal as you start to move. Your brakes should feel sharp and not pull to one side.
- If your brakes feel spongy rather than sharp, and are slow to react, you should take your car to a mechanic.
- Alternatively, you can try a static brake test. Check your brakes before moving. Whilst doing this, feel for any resistance - and make sure that the brake pedal doesn’t go all the way to the floor.

Brake light flashing - and colours explained

Brake system warning lights may differ from vehicle to vehicle. However, if your brake system warning light is on all the time, a faulty brake light is the most likely culprit. Sensors recognise when the pedal is being used, and if they are faulty, your brake system warning light will stay on continuously.

Make sure to check whether your parking brake is engaged if the warning light persists. If it isn’t, but the warning light remains, you may need to adjust your brake pedal, replace the brake pads, or fix a leak and replenish your brake fluids.

However, if your brake warning light flashes, this can indicate a more urgent issue. If the light is flashing and you find that you have to press the brake further than usual, pull over as soon as it is safe to do so, and call your breakdown provider.

In some vehicles, car dashboard warning lights may display in different colours to highlight the severity of the braking issue.

Colours such as orange, amber, or sometimes even blue or green, indicate that you should examine your brakes as soon as it is convenient. However, if you see a red warning light, this means immediate action is required.

Read your owner’s manual carefully so that you’re familiar with each variation of the brake system warning light for your vehicle.

The importance of addressing brake issues quickly

If you fail to address brake issues in good time, there are several possible implications:

Faulty brakes will affect your car’s braking efficiency. As such, stopping distances will increase, as will the likelihood of skidding – and your risk of being involved in a road accident.
If you leave faulty brakes unchecked, they will eventually fail completely. If your brakes fail when you’re driving, you could be involved in a serious collision.
Worn brake pads can also damage your brake discs. This will shorten their lifespan, so they’ll have to be replaced sooner.
If you have an active brake system warning light, pay attention to whether it is flashing. If it isn’t, get your car checked at your earliest convenience. If the light is flashing, call for your car to be towed to a garage.
If the light is solid, but your brakes feel normal (and your brake fluid levels are optimal), drive to a repair centre for a diagnosis. There could just be an issue with a sensor.
If your brakes feel faulty, pull over immediately and arrange for your car to be towed to a garage. Driving with a faulty brake system can cause further damage to your car, including total brake failure.

Frequently Asked Questions

If your brake system warning light comes on, make sure that your parking brake is disengaged. If it is (or if the light persists after disengaging the parking brake), we advise against driving.

Instead, you should call your mechanic to tow and inspect your vehicle.

Yes, it can. This typically occurs because your brake fluid is already low, and when it's cold, the fluid contracts. Therefore, the fluid will dip below the minimum level, triggering the warning light.

You can’t reset a brake light. Instead, you’ll have to resolve the issue that’s triggered it.

For example, your parking brake may be on, or your brake fluid level may be low. If you’re unsure what’s causing the issue, refer to your owner's manual - or take your vehicle to a mechanic for inspection.

The key difference is that the ABS warning light is controlled by a computer module. If you’re dealing with an ABS warning light, there may be trouble codes stored, enabling the mechanic to determine the source of a fault within the anti-lock braking system.

However, the brake system warning light merely indicates that there’s a fault within the braking system.

If both warning lights come on, pull over as soon as it is safe to do so, and call your breakdown provider.

Either of these lights could indicate a major braking fault. Continuing to drive in this scenario would put you and other road users at risk.

If your brake warning light flashes when pressing on the pedal, this could be down to hydraulic loss or low brake fluid.

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