Q: I hear a hissing sound when driving, and it only stops right after applying the brake pedal.

asked by on

I would just like to know the problem, and if I have to replace any parts. Thank you.
My car has an automatic transmission.

A likely cause of the hissing sound is a leak in the atmospheric valve within the power brake booster. The reason the sound ceases when you apply the brakes is because the vacuum valve within the booster closes upon pedal application, thus cutting off the air flow into the booster through the atmospheric valve where the hissing noise is being generated. If indeed this is diagnosed as the cause, in an examination by YourMechanic, the recommended fix would be to replace the brake booster. However, other sources of vacuum leaks would have to be ruled out as well. If you desire this to be inspected by YourMechanic, please fee free to follow up and request a hissing noise at brake pedal diagnostic.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. I hear a hissing sound when driving, and it only stops right after applying the brake pedal.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Can't do case relearn due to the scan tool not recognizing its in park. Gear indicator goes out on PN31. Changed nss no change.

Disconnect and check the ECM and switch connector on the transmission. Make sure the connectors are clean and free of any corrosion and apply dielectric grease to the connections. The harness and connections are known to get fretting corrosion that...

Q: My car is doing something strange when i turn on my a\c my fans wont kick on right away like a delay or something

I am not exactly sure on your specific model, but many Japanese cars have a/c systems that cycle the fans on and off as needed. So instead of the fans turning on as soon as you turn on the a/c,...

Q: How do I turn on the rear window defogger?

The rear window defogger helps you maintain maximum visibility out of your rear window. To turn on the rear window defogger, press the REAR button on the climate controls. The defogger will stay on for 10 minutes, or until you...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.