Why Does My Car Accelerate When I Brake?

It can be extremely unsettling when you go to hit the brakes, and you feel the car try to accelerate. This can cause confusion, terror, and danger, so knowing why this is happening is extremely important!

Possible common causes for a car to accelerate when braking include a stuck throttle, pedal confusion, vacuum leak, faulty cruise control, or malfunctioning engine control module.

When you press the brake pedal in your car, it should slow down and stop. But sometimes, the car might move faster. This is called “accelerating when braking.”

This blog post aims to provide an overview of the potential causes of a car accelerating when braking. This phenomenon can be especially troubling for drivers who have never experienced it, and it is important to understand the various factors that could be causing the issue.

It is important to diagnose each potential issue to ensure your safety while driving.

A car is accelerating when the brakes are engaged.

Causes of Car Accelerating When Braking

Drivers who experience their car accelerating when braking can be in a concerning and potentially dangerous situation.

Stuck throttle

A stuck throttle can be one of the main causes of your car accelerating when you press the brakes. This happens when the accelerator pedal gets stuck in an open or partially open position, meaning your car will still get fuel even when you hit the brakes.

The issue is generally caused by an obstruction in the accelerator cable or a fault with the electronic throttle control system. Sometimes, it may be due to a malfunctioning cruise control system.

When a stuck throttle occurs, it can be difficult to stop your car because it receives fuel from the engine even as you press down on the brakes.

This could lead to dangerous situations where your vehicle accelerates quickly and unexpectedly, which could cause an accident if you cannot react quickly enough.

Brake pedal and accelerator pedal confusion

Brake pedal and accelerator pedal confusion can be another possible cause of your car accelerating when you press the brakes. This occurs when either the driver is unfamiliar with the vehicle, or there is an issue with how the pedals are laid out.

For example, if you usually drive a manual transmission car and suddenly switch to an automatic car, you may mistakenly use the brakes instead of the accelerator. This could cause your car to accelerate even if you press down on the brakes.

Another potential reason for this confusion is when drivers become accustomed to the layout of their vehicles and press down on what they think is the brake, but it is the accelerator. The pedals are often close together, so it can be easy to make a mistake and press down on the wrong one.

To prevent this, drivers must be familiar with their vehicles and how far apart each pedal is located so they do not accidentally hit them.

Additionally, many modern cars come with two brake pedals located at different heights to make sure that drivers don’t confuse them with each other.

Vacuum leak

Vacuum leaks can cause your car to accelerate when you press the brakes. This is because a vacuum leak can create an imbalance in the air pressure between the engine and the brake system.

When this happens, it can cause the brakes to malfunction and release too much air pressure when applied, making your car accelerate instead of stopping.

This issue occurs when a crack or hole in the vacuum line leads from the engine to the brake booster. This break in the line causes a decrease in air pressure, affecting how the brakes work.

To diagnose a vacuum leak, you should have your vehicle inspected by an experienced mechanic so they can determine if there is any damage to the vacuum lines or any other problems with your brake system.

If they find a problem, they can fix it and make sure your brakes work properly again.

Faulty cruise control

Controls on a car's steering wheel to adjust or engage cruise control.

Faulty cruise control can also be responsible for your car accelerating when you press the brake.

Cruise control is a system that allows you to set and maintain a constant speed on the highway, but if it is not working properly, it can cause your car to accelerate instead of slow down when you press the brakes.

This can usually happen if there is an issue with the cruise control switch, wiring, or actuator. It can also occur if the sensors that detect the current speed of your vehicle are not sending proper signals to the engine.

To diagnose this type of problem, it’s important to have your car checked by a professional mechanic who can determine what is causing the issue and repair any part that needs to be replaced.

Once they identify and fix any underlying problems with your cruise control system, they can help ensure your brakes work correctly and reliably in all conditions.

Malfunctioning engine control module

The malfunctioning engine control module (ECM) can be one of the main reasons a car accelerates when braking. The ECM controls your car’s electronic systems, including fuel and emissions.

When the ECM isn’t functioning properly, it can cause your car to accelerate instead of slowing down when you hit the brakes. This could happen because the ECM sends incorrect signals to the engine or fuel injectors, causing them to fire more often.

Another possible reason is that your ECM may be out of calibration and not responding correctly to changes in throttle position or air-fuel ratios. In these cases, it’s important to have your ECM tested by a qualified mechanic who can pinpoint and diagnose any issues with the system.

Once they identify any problems with the ECM, they can repair or replace it so that your brake system works as intended again.

Symptoms of Car Accelerating When Braking

The most obvious symptom of a car accelerating when braking is when you press down on the brake pedal, and your vehicle does not slow down but instead accelerates.

You may notice that the engine revs higher than usual when you apply the brakes, or it may take more effort to stop your car.

Increase in RPM

Rev counter showing an increase in RPMs.

When a car accelerates when braking, there will likely be an increase in the RPM (revolutions per minute) of the engine. This happens because the engine receives more fuel than it needs to maintain a constant speed. As a result, the increased fuel causes the engine to work harder and faster, increasing RPM.

When this happens, you may also notice that your car takes longer to slow down when you hit the brakes. This is because the brake pads cannot keep up with the increased RPMs of the engine and can’t provide enough friction to bring your car to a stop as quickly as normal.

In addition, your vehicle may not respond as quickly or smoothly when shifting gears or changing speeds. Higher RPMs cause more strain on your transmission and driveline parts, leading to slower gear shifts and less consistent acceleration.

Brakes Not Responding As Expected

When a car accelerates when braking, it can be due to various problems with the braking system. For example, the brakes may not provide sufficient friction or pressure on the wheels to slow them down.

This could be caused by worn brake pads or low brake fluid levels. It could also be an issue with the brake caliper or master cylinder.

The issue could also be related to a problem with the powertrain system, such as a sticking throttle plate, faulty air-fuel ratio sensor, or worn-out spark plugs and wires.

All of these components work together to control how much fuel is sent to the engine, and if something is malfunctioning, it can cause your car to accelerate instead of slowing down when you press on the brakes.

Improperly adjusted drum brakes can also contribute to this problem, as they can cause your vehicle’s rear brakes to apply too much pressure and thus make it accelerate instead of slowing down.

Lastly, a blockage in the exhaust system can lead to increased backpressure that forces more fuel into the engine and causes it to accelerate when you press on the brakes.

Unusual Sounds or Vibrations

A badly worn brake pad is set beside a new pad for comparison.

Unusual sounds or vibrations when braking can indicate various problems with the brakes. It could be an issue with the brake pads, such as them becoming worn down or cracked.

Other potential issues include a lack of lubrication on the brake calipers, sticking brake drums, and warped rotors.

Another possibility is that air gets into the brakes, reducing friction and reducing braking power. Brake fluid leaks can also lead to this problem. Furthermore, worn-out hoses and lines can cause air to enter the system.

Vibration during braking could also indicate a problem with wheel alignment or balance. This could be caused by incorrect tire pressure or a bent rim from hitting obstacles such as potholes while driving.

Car Lurching Forward Unexpectedly

If your car is lurching forward unexpectedly when you press the brakes, it could be caused by several issues.

A worn-out or damaged brake master cylinder can cause this problem, as it is responsible for distributing the brake fluid to all four brake calipers evenly and efficiently.

A vacuum leak in the powertrain system can also cause your car to accelerate instead of slow down.

This could be caused by a faulty hose that’s no longer providing enough vacuum pressure to the engine, resulting in an overabundance of fuel being sent to the engine and making it essentially ‘rev up’ when you press on the brakes.

Other possible causes include problems with the transmission, such as a malfunctioning shift solenoid or a dirty filter, as these can prevent proper shifting.

Warped rotors or misaligned wheels can also increase resistance and/or jerking motion when braking, making it feel like your car is accelerating instead of slowing down.

Risks of Car Accelerating When Braking

One of the biggest risks of a car accelerating when braking is it can cause an accident. If the driver doesn’t have enough time to react to the sudden increase in speed, they may be unable to maneuver and avoid a collision.

Acceleration when braking can also lead to braking difficulties due to loss of control or instability of the car.

Increased Risk of Accidents

Increased risk of accidents can have disastrous consequences, as a car suddenly accelerating when braking can cause a crash with other vehicles, pedestrians, and property. A driver may not have the necessary time to react if their car accelerates instead of slowing down.

Statistics show that the risk of an accident increases significantly when cars accelerate when braking. According to the National Highway Traffic Safety Administration (NHTSA), nearly 10% of all crashes are caused by brake failures or other brakes-related issues.

This means a malfunctioning system could be responsible for up to one million deaths and injuries each year in the United States alone.

In addition, studies suggest that acceleration instead of slowing down when the brakes are applied increases the likelihood of a crash by two-thirds.

This makes it all the more important to identify malfunctions early on and take action before any potential tragedy occurs.

Damage to the Car’s Engine and Transmission

Damage to the car’s engine and transmission can occur when a car accelerates when braking. When brakes are applied, and the vehicle is already in motion, the increased friction between parts can cause excessive wear and tear on essential components.

This includes damage to the engine, gearbox, drivetrain, and wheel bearings which may result in costly repairs or replacement.

Additionally, the sudden force of an accelerating car when braking can create a jerking motion that puts additional strain on transmission parts such as clutch plates, gears, shafts, and U-joints.

If left unchecked, these problems could lead to premature breakdowns or even total failure of the car’s transmission system.

In addition to these mechanical issues, cars that accelerate while braking also face other risks, like increased fuel consumption due to increased acceleration from harder braking.

This means drivers will spend more gasoline to keep their vehicles running efficiently.

Drivers must identify malfunctions in their vehicle’s brakes early to avoid costly issues.

How to Prevent Car Accelerating When Braking

The best way to prevent a car from accelerating when braking is to have regularly scheduled maintenance done by a certified mechanic.

Regular Maintenance of the Car

Mechanics are busy conducting maintenance inspection of a car.

Regular car maintenance is essential to ensure that it runs smoothly and safely. By regularly inspecting and servicing the brakes, drivers can help prevent acceleration when braking.

This includes checking for wear and tear on the brake pads, rotors, calipers, and other components. Additionally, brake fluid should be checked to ensure it is still at optimal levels.

Drivers must know their vehicle’s braking system performance to reduce the risk of excessive wear and tear on transmission parts resulting from accelerating while braking. Any signs of sudden or abnormal jerking or vibration should be addressed immediately by a certified mechanic.

Drivers should also be mindful of their driving habits and not over-applying the brakes. This can lead to increased wear on these components and fuel consumption due to the added acceleration from harder braking.

It is also important for drivers to ensure they are using reliable brake fluids which provide adequate lubrication and protection against breakdowns in extreme temperatures or terrain conditions.

For optimal safety, drivers should keep up with regular inspection and maintenance schedules for their cars as the manufacturer recommends to keep their vehicles running efficiently and reliably for years to come.

Keeping an Eye Out for Symptoms

Keeping an eye out for symptoms of a car accelerating when braking is essential for drivers. It is important to be aware of sudden or abnormal jerking or vibrations when the brake pedal is pressed.

Additionally, drivers should pay attention to changes in sound, such as grinding noises, squealing noises, and other indicators of faulty brakes or inadequate lubrication.

Drivers should also watch for excessive wear on the brake pads, rotors, calipers, and other components. By regularly inspecting these parts and ensuring they are in good condition, drivers can reduce the risk of brake failure resulting from acceleration when braking.

Additionally, they can reduce wear on transmission parts due to harder braking and fuel consumption from added acceleration due to more aggressive braking.

Finally, it is important to ensure that reliable brake fluids provide adequate lubrication and protection against breakdowns in extreme temperatures or terrain conditions. This will help reduce the risk of acceleration when braking and keep cars running safely and efficiently.

Avoiding regular sudden braking

Avoiding sudden braking is an essential part of driving safely and efficiently. When a driver brakes suddenly or slams on the brakes, it can cause the car to accelerate due to increased momentum.

This can be dangerous as it can increase the risk of colliding with other cars or objects around them.

Drivers should ensure their vehicles function properly by conducting regular maintenance and inspection schedules to avoid sudden braking.

This will help keep the brakes in good condition and reduce the likelihood of brake failure resulting from acceleration when braking.

In addition, drivers should practice proper defensive driving techniques such as maintaining a safe distance between themselves and other vehicles, anticipating potential hazards on the road ahead, and paying attention to their speed and how much time they need to stop at intersections and turns.

Furthermore, drivers should always stay aware of their surroundings by using their mirrors regularly and checking blind spots before changing lanes.

The more prepared a driver is, the less likely they are to make sudden maneuvers or engage in risky behavior, which can lead to unnecessary acceleration when braking.

Finally, drivers should use gradual braking techniques when possible to minimize acceleration when coming to a stop. Gradual braking will also help reduce wear on transmission parts and fuel consumption due to harder braking.

Pulling Over and Turning Off the Engine if the Problem Persists

A woman is pulled over on the side of the road with a broken down car 
and is calling for a service to help her.

If a driver experiences persistent acceleration when braking, they should immediately pull over and turn off the engine.

This will help reduce the risk of further acceleration and potentially hazardous situations. Additionally, it will give the driver time to inspect their vehicle for any underlying issues that might be causing the problem.

The driver should check for brake fluid leaks, worn brake pads, loose or disconnected brake lines, or other problems that could lead to sudden acceleration when braking.

If any of these are detected, the driver should take their car to a qualified mechanic as soon as possible for repair.

Moreover, drivers should inspect their tires for excessive wear, which can lead to traction problems and poor braking performance. Worn tires can also cause the car to slip and accelerate when coming to a stop.

As such, drivers must maintain their tires regularly and replace them with quality options.

Taking proper precautions when driving can help reduce the risk of sudden acceleration when braking.

By maintaining regular vehicle maintenance and practicing safe driving habits, drivers can ensure that they experience smooth braking without any unexpected acceleration or other dangerous situations.


Taking proper precautions and regularly maintaining the vehicle can reduce the risk of sudden acceleration when braking.

To avoid sudden acceleration, drivers should check for brake fluid leaks, worn brake pads, loose or disconnected brake lines, and excessive tire wear. Safe driving habits like gradual braking and pulling over can also help.

If these issues occur, the car may accelerate instead of stopping when brakes are applied. Inexperienced drivers should apply gradual braking and increase pressure gradually to avoid unexpected acceleration that could lead to accidents.

Symptoms of sudden acceleration may include the vehicle beginning to accelerate when brakes are applied or the pedal feeling different than normal.

Regular vehicle maintenance can help detect any underlying problems that could cause this issue, and drivers should check their brakes regularly to ensure all parts function properly.

Following these steps, drivers can minimize their chances of experiencing sudden acceleration.