sixpoint

Vehicle is 1 yr old with 8,000 miles and sometimes while I am completely at rest and not moving (in traffic or at a red light) the brake pedal pulses and the car produces a faint pinging sound from under the dash or in the engine compartment. Its annoying & uncomfortable. Rate is about 2 pulses per second so its rather quick & lasts until I shut the car off. This has happened approx 10 times in the 1 year ive owned it. My wife & I have both noticed it while driving the car. Not sure if the braking system is electric or vacuum? ABS issue? Could it be a sensor, relay or connection? Problem is intermittent & doesnt happen all the time, so I cant get it to misbehave for the dealer. Anyone else have this? Any ideas would be appreciated. Thanks!

kyoshiro

a guess could possibly be the brake fluid losing pressure?
see if you can reproduce it in your garage and see if theres any leakage under.
however im no mechanic so its just symptom + a guess.

GLKKa2H

When the Anti-lock Braking System (ABS) kicks in, you will feel pulsing in the brake pedal. However does it (normally) work from a speed of about 8 km/h upwards.

The Brake Assist System (BAS) automatically boosts the braking force (an electric pump pressurizes brake fluid) if you depress the brake pedal quickly. You will feel a pulsing in the brake pedal only if ABS intervenes (to prevent the wheels from locking).

On uphill grades, the hill-start assist system maintains the pressure in the brake system for approximately 1 second after you have released the brake pedal. Will not cause a pulsating brake pedal.

As the problem is intermittent, could it be that it happens in uphill grades every time?

sixpoint

When the brake pedal starts pulsing underfoot Im at a dead stop with my foot firmly engaging the brake. The car is not moving. The automatic transmission is in gear/ in drive position.

sixpoint

Anyone ?

MBRedux

It sounds like a malfunctioning brake assist vacuum booster. If it's happening often I would go to the dealer and have it checked out. You don't want to fool around with brakes.

Good luck and please keep us all informed as to their diagnosis.

sknight

Yeah.

1 year old car? Safety device? Warranty. Go to the dealer. The internet is not going to fix the problem, especially when a repair won't be out of pocket for you.