What are the reasons why my car shuts off when brakes are pressed? It happens for various reasons, such as a faulty brake booster, low fuel pressure, or a bad fuel pump.
Aside from the inconvenience, this problem can signify a poor brake system you need to consider. You should not drive your automobile until you can fix this fault.
Cars stopping when braking is popular in vehicles with carburetors, though it also exists in injection engines.
Keep reading the article below to understand the common causes that can lead to automobile stalling.
After determining the exact cause of this problem, you can find effective methods to fix it. Scroll down for details!
What Are Causes If My Car Shuts Off When Brakes Are Pressed?
A faulty brake booster (including the system check valve and rubber diaphragm) leading to engine vacuum leaking is the most common cause of a car shutting off when you forcefully brake.
Yet, there are various other causes when an automatic car stalls when braking. They comprise a failing speed sensor, a defective fuel pump, and a failing or damaged engine control unit.
Why Does A Poor Vacuum Brake Booster Make My Car Shut Off?
Why Does My Car Shut Off When Getting A Poor Vacuum Brake Booster?
A vacuum brake booster lies between the primary brake cylinder and the pedal. It helps you reduce the force when pushing the car’s brake pedal.
A vacuum hose connects the vacuum brake booster to the intake manifold. This part’s design also comprises a membrane apart from other things.
The poor or broken membrane might explain why a car turns off when braking.
The broken membrane can not form a vacuum, so the air from the braking system will go into the fuel system. If you hit the brake pedal, your vehicle will stall.
Instead of repairing it, you should replace the car’s vacuum amplifier when it fails.
How To Inspect A Poor Vacuum Brake Booster?
Before replacing it, follow two simple ways below to see whether the car’s vacuum brake booster fails.
First, turn off your car, press the brake pedal and release it several times to make it harder.
The vacuum hose is still good if the brake pedal pressing gets softer at a lower position after starting the car. Yet, when it keeps motionless, you must conduct a thorough investigation.
In a second way, halt your vehicle by braking after operating for a while. Push the braking pedal for around 20-30 seconds. The vacuum brake booster works properly if the pedal doesn’t resist your foot.
Can A Low Fuel Pressure Cause A Car to Shut Off?
Yes, it can. It can cause car stalls when braking hard, limited acceleration, noisy idle, or vehicle misfires.
An unresponsive throttle can produce low fuel pressure, as the proper combination of fuel and air is dependent on it.
A fuel pressure failure is also one of the main reasons your check engine light flashing and your engine stalling.
Its symptoms are your vehicle running hot, low fuel economy, and black smoke from the exhaust system.
How Does Leaking Brake Fluid Cause A Car To Stall When Braking?
Another cause is the main cylinder leaking brake fluid from the internal or external cylinder boot. When there is air in the line or brake fluid, your car dies when brakes are applied.
Air can reach your engine system when a hole develops somewhere along the tube.
This hole makes the air enter the brake fluid and impairs correct braking pressure. Thus, there is a reduction in pressure when you brake your car.
Besides, a brake line obstacle, including a pinched brake line or a chunk of corrosion, can also cause stalling. A vacuum leaking in the anti-lock braking system can shut off the car.
Does Faulty Idle Air Control Actuator Make A Car Cut Off While Braking?
Yes, it does. The idle speed sensor or air control actuator regulates the RPMs when idling the automotive engine system.
The electronic control unit (ECU) will send signals to this actuator, telling it what RPM to keep the engine system for a safe and smooth idle and running at a consistent pace.
When you press the brake pedal, you can see the actual engine RPM at idling status. The car receives a no-idling speed indication.
Beside, the clogged EGR valve is also a possible root. If your EGR valve is in a blocked, unclean, or malfunctioning situation, your car cuts off when braking.
It becomes an abnormal idle or stumbles, whether jammed closed or open.
Why Does A Car Shut Off When Braking With A Bad Vacuum Brake Booster Hose?
Depressurization of the line connecting the intake manifold and the vacuum brake booster is why your car shuts off when braking.
In case the hose fails, the additional air will penetrate, resulting in an improper air-fuel combination, causing the car to shut off when you press the brake pedal.
Detach this hose out of the vacuum booster to inspect it. Start the vehicle and use your finger to press the hole in the damaged hose.
If the engine is covered, it will give RPMs an automatic increase before lowering them.
Check the valve equipped at the hose’s end where it links to the amplifier as well. The fastest method to determine the vacuum brake booster hose failure is to contact it.
If it crosses air, the brake pedal can operate very difficult, and pressing it will require more effort.
In case pushing the brake pedal requires more effort and increases the braking distance, the vacuum brake booster hose’s malfunction can cause safety concerns. So, it’s critical to tackle this problem soon.
Can Line Obstruction Cause A Car To Turn Off When Braking?
Yes, it can. Line obstruction is another culprit that explains why your automatic car stalls when braking hard. It originates from debris, pinched lines, or rust.
Something could prevent brake fluid from reaching a segment of the system. Thus, you can visually inspect the brake line system to fix or replace it if it fails.
Why Does My Car Die If I Brake When Having A Bad Fuel Filter Or Pump?
Another cause is bad pumping brakes when car is off. This problem can clog the fuel filter.
If the fuel pump can not supply enough power or the necessary fuel amount to the engine system, it results in installing the vehicle.
Once you detect a bad fuel filter, you should change it as soon as possible. Likewise, replace the fuel pump right away in case you sense any problem.
Another less popular cause of cutting brakes on a car is poor high-voltage wires. You should examine the negative contact cable’s quality from the battery. If it has bad contact, your engine can shut off immediately.
What Should I Do If My Car Shuts Down When Braking?
First, you should inspect the vehicle’s transmission to see if it gets debris or dirt. Besides, checking and cleaning the fluid levels and filters is also important to keep your engine.
Check transmission fluid levels under the hood systematically to get the optimal status. It is also essential to keep an eye on friction levels and your vehicle’s clutch plate to prevent them from corrosion.
You should also ensure your directional signals and relay valves are clear. If you have a faulty oxygen sensor, fix it to solve the car stalling problem.
You should also seek holes in the hoses and look for broken or corroded wires that cause your car to stall.
What Does A Car Stalls When Braking Mean?
When your car stalls when braking, it can get a brake booster vacuum hose obstruction or a failing master cylinder.
It’s also possible that the ABS is leaking. It is difficult to identify the root causes and find the best solution without professional assistance.
Conclusion
Have you determined why your car shuts off when brakes are pressed? The causes include the poor brake booster, low fuel pressure, faulty idle air sensor, bad fuel pump, or line obstruction.
The poor vacuum brake booster as well as its hose are the most prevalent cause of this problem.
So, you should get a thorough check of these two components. If they’re not good, take your vehicle to a mechanic shop for a complete inspection.
Thank you