Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Brake Booster Vacuum Sensor

Brake booster vacuum sensor

Brake booster vacuum sensors are an electronic component found on many vehicles equipped with vacuum pumps for their brake boosters. They are usually installed in the brake booster and work to monitor the amount of vacuum present inside of the booster. They monitor the vacuum level to ensure that there is always enough vacuum present for the power brakes to operate correctly, and will set off a brake or service booster light when they detect that the vacuum has fallen below acceptable levels.

When they do fail, the computer loses an important signal as the vacuum measured by the brake booster vacuum sensor is what allows the power assisted brakes to work. Usually, a vehicle with a failed brake booster vacuum sensor will produce a few symptoms that can notify the driver of a potential problem that should be serviced.

Stiff brake pedal

One of most commonly associated symptoms of a problem with the brake booster vacuum sensor is a stiff brake pedal. A stiff brake pedal is usually caused by there not being enough vacuum present due to a problem with the brake booster vacuum pump. However, if the pedal become stiff and the brake or service booster light is not illuminated, then that means the sensor is not picking up on the low vacuum levels and may be having a problem.

Illuminated Check Engine Light

Another symptom of a problem with the brake booster vacuum sensor is an illuminated Check Engine Light. If the computer detects a problem with the brake booster vacuum sensor signal or circuit, it will set off the Check Engine Light to alert the driver that a problem has occurred. A Check Engine Light can also be set off by a variety of other problems, so it is important to have the computer scanned for trouble codes before proceeding with any repairs.

The brake booster sensor is an important piece of the braking system for vehicles equipped with brake booster pumps. They monitor an important signal for the vacuum that allows the entire power brake system to work. For this reason, if you suspect that your brake booster may be having a problem, or your Check Engine Light has come on, have the vehicle’s brake system diagnosed by a professional technician, such as one from YourMechanic. They will be able to determine if your car needs a brake booster vacuum sensor replaced, or if another repair is needed to restore functionality to your brake system.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem What the P0121 code means P0121 is a generic OBD-II code which indicates that the Engine Control...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...

Related questions

Q: Bad crank sensor

Hello. Just about anything is possible but it is unlikely. I have seen crank sensors go bad and cause many issues, but if you are not having any other issues then I think that it is unlikely. If I knew...

Q: Vacuum leak

Hi. This is a very common failure on vehicles like yours. So common, in fact, that there is a technical service bulletin (TSB) on it. The TSB is XT303-13 and it addressed the hissing sound from under the hood, as...

Q: 95 dodge neon went from drove to park kinda rough went to move the car won't come out of park could it be brake light switch

It appears that your vehicle is stuck in Park. A few different things can cause this to happen to your Dodge Neon with the simplest thing being a faulty brake switch (located on the brake pedal). One quick way...