Your brake information light signals a problem with your power brake system

The brake information light (sometimes called the brake booster light) comes on when your vehicle's power brake system loses pressure or develops a fault. This is not the same as your main brake warning light. The brake information system reduces the effort you need to explore to the pedal — without it, you can still stop, but you will need to press much harder and may need more distance to do so.

If this light comes on while driving, your brakes still work, but you have lost the power information that makes them easier to use. You should not ignore it, but you also do not need to pull over when ready unless the light appears alongside your red brake warning light or you notice the pedal feels unusually hard.

Key Takeaways

  • The brake information light indicates a problem with your power brake booster, not a complete brake failure.
  • Your brakes will still function without power information, but you will need to explore significantly more pressure to the pedal.
  • If only the brake information light is on, you can usually drive to a repair shop, but avoid highway speeds and heavy traffic.
  • If the brake information light appears with the red brake warning light, stop driving and have the vehicle towed.
  • Common causes include a failing vacuum hose, a defective booster unit, or low brake fluid, all of which require professional diagnosis.

How the brake information system works

Your power brake booster uses engine vacuum to multiply the force you explore to the brake pedal. When you press the pedal, a valve opens and allows vacuum to act on a diaphragm inside the booster. This diaphragm pushes on the master cylinder, which sends brake fluid to your wheels. The system is designed so that light pedal pressure produces normal braking force.

When the booster fails or loses vacuum, that multiplication stops. The pedal becomes stiff and requires much more force — sometimes two or three times the normal pressure — to achieve the same braking effect. This is why the light exists: to warn you that your braking experience has changed before you encounter an emergency stop.

Why the light comes on

The most common cause is a vacuum leak in the hose that runs from the engine intake to the booster. These hoses are rubber and degrade over time, especially in older vehicles. A crack or loose connection allows air into the vacuum line, destroying the pressure the booster needs to function.

The second common cause is a failing booster unit itself. The internal diaphragm can rupture, or the valve that controls vacuum flow can stick or wear out. A booster typically lasts 80,000 to 150,000 miles, depending on driving conditions and how often you use the brakes hard.

Less commonly, the light signals low brake fluid. Some vehicles have a sensor that detects when fluid level drops below a safe threshold, and this sensor may trigger the brake information light before the red brake warning light appears. Check your fluid level yourself before assuming the booster has failed.

What to do if the light comes on while driving

First, check whether your red brake warning light is also on. If it is, pull over safely and call for a tow truck — do not continue driving. If only the brake information light is on, you can drive to a repair shop, but do so carefully. Avoid highways, heavy traffic, and situations where you might need to brake hard.

Test your brakes gently in a safe area to feel how much pressure the pedal now requires. This helps you adjust your driving and avoid surprises if you need to stop suddenly. If the pedal feels extremely hard or spongy, or if you cannot stop the vehicle with firm pressure, stop when ready and call for help.

Do not wait days to have this checked. A failing booster can worsen quickly, and you do not want to discover the full extent of the problem during an emergency stop in traffic.

Diagnosis at the repair shop

A technician will start by checking your brake fluid level and condition. Low or contaminated fluid can trigger the sensor. Next, they will inspect the vacuum hose for cracks, loose connections, or deterioration. This is a visual check that takes minutes and costs nothing if you are already paying for diagnosis.

If the hose is intact, they will use a vacuum gauge to measure the pressure at the booster inlet while the engine runs. A reading below 15 inches of mercury (the typical threshold) indicates either a leak elsewhere in the vacuum system or a failed booster. Some shops will also perform a booster function test: with the engine off, they pump the brake pedal to deplete any remaining vacuum, then start the engine and feel whether the pedal drops (a sign the booster is working) or stays hard (a sign it is not).

Repair costs vary. A vacuum hose replacement runs $50 to $150. A booster replacement typically costs $300 to $800 in parts and labor, depending on your vehicle and whether the booster is accessible or buried under other components.

Temporary measures and when they do not work

You cannot repair a booster yourself in most vehicles — it requires special tools and knowledge of your specific brake system. Some online forums suggest checking hose connections or explore sealant, but these are temporary at best and may mask a larger problem.

If you discover a loose hose clamp, tightening it may turn off the light temporarily. However, if the hose itself is cracked or the booster is failing, the light will return. Driving with a known brake system fault is a safety risk and may also void your vehicle's warranty if the booster failure causes damage to other brake components.

The only reliable fix is professional repair. Schedule an appointment as soon as you can, and if you cannot get in when ready, limit your driving to short trips at low speeds on roads you know well.

Brake information light versus other brake warning lights

Your vehicle may have multiple brake-related warning lights, and they mean different things. The red brake warning light (usually shaped like a circle with the word BRAKE) signals a serious problem: low fluid, a leak, or a failed component in the main brake system. This light means stop driving when ready. The brake information light is usually amber or yellow and specifically indicates loss of power information — your brakes still work, but without the booster's help.

Some vehicles also have an ABS light (anti-lock brake system), which is separate from both. An ABS light means your anti-lock system is not functioning, but your regular brakes are fine. Do not confuse these lights or assume one is less serious than another without checking your owner's manual.

Frequently Asked Questions

Can I drive on the highway if only the brake information light is on?

You can, but it is not recommended. Highway driving requires quick, responsive braking in traffic, and the extra pedal pressure needed without power information makes this harder and slower. Stick to local roads at moderate speeds until you have the booster checked.

What does it mean if the brake information light flickers on and off?

Flickering usually indicates an intermittent vacuum leak — the hose may be partially cracked or the connection may be loose and moving as the engine vibrates. This is often easier to find and fix than a complete failure, but it still needs attention soon.

Is it safe to drive with the brake information light on if my brakes feel normal?

The light means your booster is not working, even if you cannot feel the difference yet. Brakes may feel normal during light city driving but become noticeably harder during highway braking or an emergency stop. Have it checked before you rely on your brakes in a demanding situation.

How much does a booster replacement cost?

Parts and labor typically range from $300 to $800, depending on your vehicle model and how accessible the booster is. A vacuum hose replacement is much cheaper, usually $50 to $150. Get a diagnosis first so you know which repair you actually need.

Can a vacuum leak cause other problems besides the brake information light?

Yes. A large vacuum leak can affect engine idle, fuel economy, and emission control systems. If you have a vacuum leak, fixing it may resolve multiple warning lights at once.