[zjennings]

Anyone else getting a buzz sound occasionally when coming to a stop? I get it once in a while if I am breaking pretty hard, then let up on the break right before I stop. Dealer said they couldn't find anything wrong with the regenerative breaking. It just started after I hit about 8k on my odometer.

 

[zjennings]

If you're braking hard are you sure its not the ABS?

The Buzz is like a spring unwinding or gears grinding. It is NOT throughout breaking. It happens for a split second when I let off the break after breaking hard, if the car is still moving.

 

[zjennings]

Update: an intermittent noise coming from driver's side under the dashboard is an electric motor that builds up pressure in the brake booster system. Since the gas engine is not always running, vacuum needed for the brake booster system is not always available.
Lexus service master technician confirmed that gas engine will not start under any circumstances unless car was not powered off. We must have forgotten to hit the power off button when we parked the car, so, once battery level dropped to certain level gas engine kicked in. Perfect explanation and it makes sense. I was able to replicate the issue with a note that once I left the car, it made three tones which was an indication the car was still powered on and key was not detected. Got to be more careful in the future. This hybrid and keyless start is soo new to us.

This is exactly what they told me, but it is NOT acceptable! Passengers in a Lexus should never be freaked out by a sound coming from your breaking system! The factory recommended a double flush of the breaking system, to try to eliminate the sound. I would expect this sound from a cheaper brand; but with a luxury brand, strange noises like this are unacceptable.

I will let you know if the double-flush fixes the noise.