Symptoms of a Bad or Failing 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.


Next Step

Schedule Brake System Inspection

The most popular service booked by readers of this article is Brake System Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

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

Recent Brake System Inspection reviews

Excellent Rating

(334)

Rating Summary
309
14
4
1
6
309
14
4
1
6

Jesse

17 years of experience
127 reviews
Jesse
17 years of experience
Jaguar S-Type V8-4.2L - Brake System Inspection - Palm Coast, Florida
Jesse showed up for the appointment timely and ready to work. He was polite and professional and competent. He took sufficient time to inspect the vehicle and explained in layman's terms any problems and whatever corrective work that might be required. I highly recommend Jesse and hope to have him service my vehicles again in the future if needed.
Ford Escape - Brake System Inspection - Daytona Beach, Florida
Jesse arrived on time after sending notice 15 mins prior. A true professional Jesse got right down to business. He started his inspection work right away and did a thorough professional job and determined the solution to his findings. I am very pleased. He is a true expert mechanic.

Johnny

34 years of experience
392 reviews
Johnny
34 years of experience
Toyota RAV4 L4-2.4L - Brake System Inspection - Sacramento, California
Johnny arrived early which was great, he performed the inspection in less than half an hour, and gave us a complete quote for all items needing attention, including the brakes as our main concern. Johnny is fast and efficient so I scheduled the work done by him.
Ford Escape - Brake System Inspection - Sacramento, California
The convenience is worth the cost. I was also tired of the dealership not really caring about my old car. Last couple of times I had to wait well over an hour to get my car after the dealership said "It's ready!". They also wouldn't fix the things I asked saying they didn't have time and I need to come back.

Luis

30 years of experience
119 reviews
Luis
30 years of experience
Honda Accord V6-3.0L - Brake System Inspection - Northbrook, Illinois
He's excellent. On Time, honest and all repairs done quickly and correctly. Book him if he's available!

Christopher

16 years of experience
246 reviews
Christopher
16 years of experience
Nissan Sentra L4-2.0L - Brake System Inspection - Charlotte, North Carolina
Very informative and made sure to clarify on what he spoke on so that I understood what was happening with my car

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.

GET A QUOTE

Related articles

How to Replace a Brake Master Cylinder
Brake master cylinders are a key part of your car braking system. Brake master cylinder replacement helps brake pedals hold pressure when you brake.
How to Replace a Brake Booster Vacuum Sensor
The brake booster vacuum pressure sensor is a vital part of power brake operation. A Check Engine Light or a hard brake pedal are signs of failure.
How to Replace a Car Battery Temperature Sensor
The battery has a battery temperature sensor that can fail if the Check Engine Light comes on, the battery voltage is low, or the RPM curve surges.

Related questions

Slight resistance when driving forward, ABS light is on.
I would have a mechanic check it out to determine why your ABS light is on (https://www.yourmechanic.com/services/abs-light-is-on-inspection). They can check ABS codes with a scan tool to determine the problem. It may be a bad wheel speed sensor.
Difficult startup with a lot of idling when it's cold
One of the main things that can prevent a vehicle from starting in the cold is the battery. Batteries for automobiles are rated by cold cranking amps. This measurement is the amount of amperage the battery can produce at zero...
Where is the Crankshaft Position Indicator on a 1998 Infiniti QX4?
The crankshaft position sensor is typically externally mounted on the engine near the crankshaft pulley. I would recommend checking near the crankshaft pulley for this answer. If you need help with the replacement of the crankshaft position sensor (https://www.yourmechanic.com/services/crankshaft-position-sensor-replacement), I...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com