What is that noise when you come to a stop?
03-09-15, 04:52 PM
#1
Driver
Thread Starter
What is that noise when you come to a stop?
2011.
So whenever I come to a stop the car makes a noise. Not a noise like something is broken but a hybrid something or another noise that I am just not used to because this is my first car of it's type. When you come to a stop, at least when I am in slow speeds or in EV mode, the car makes a "greeeeeee--" and then gets silent. It's like a power transfer something coming from the front. I never really thought about it until my wife asked me what it was today and I had no answer other than "It's something to do with the hybrid system".
So, what is it?
So whenever I come to a stop the car makes a noise. Not a noise like something is broken but a hybrid something or another noise that I am just not used to because this is my first car of it's type. When you come to a stop, at least when I am in slow speeds or in EV mode, the car makes a "greeeeeee--" and then gets silent. It's like a power transfer something coming from the front. I never really thought about it until my wife asked me what it was today and I had no answer other than "It's something to do with the hybrid system".
So, what is it?
03-09-15, 05:23 PM
#2
The Vehicle Proximity Notification System (whew...) is a speaker under the front grill that emits a variable
tone to warn pedestrians that you are approaching using only electric drive. It is off when you are stopped,
loudest when you first lift off the brake and changes pitch as you speed up. If the IC engine fires up the sound
shuts off, in any case it goes off above 15 MPH.
Sounds a bit like blowing across a giant pop bottle, kind of a hollow "wooshie" sound. Works in reverse but
the speaker is in the front so not as effective, does really echo in a garage while backing however!
tone to warn pedestrians that you are approaching using only electric drive. It is off when you are stopped,
loudest when you first lift off the brake and changes pitch as you speed up. If the IC engine fires up the sound
shuts off, in any case it goes off above 15 MPH.
Sounds a bit like blowing across a giant pop bottle, kind of a hollow "wooshie" sound. Works in reverse but
the speaker is in the front so not as effective, does really echo in a garage while backing however!
03-10-15, 03:48 AM
#4
Driver
Thread Starter
This one doesn't sound like a woosh or a pop though, it something else. I wonder if I can record it when driving around the neighborhood, I'll give that a shot today. I only hear it when I stop, nothing else, and it sort of appears then goes away right as I am pulling up to the stop sign or light.
03-10-15, 08:19 AM
#5
Lexus Test Driver
The Proximity sounds like Darth Vader. 
What ur hearing is probably the regenerative braking system. It's charging the battery whenever u step on the brakes.
What ur hearing is probably the regenerative braking system. It's charging the battery whenever u step on the brakes.
03-10-15, 09:28 PM
#6
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This one doesn't sound like a woosh or a pop though, it something else. I wonder if I can record it when driving around the neighborhood, I'll give that a shot today. I only hear it when I stop, nothing else, and it sort of appears then goes away right as I am pulling up to the stop sign or light.
If its an audible beep then I would say it is indeed the proximity sensor.
03-11-15, 05:43 AM
#7
Driver
Thread Starter
Here is a video captured this morning, the noise can be heard at the three second mark.
CT 200h noise: http://youtu.be/AU0RFW340xk
The noise can be heard when the car is slowing down, this one was me going maybe 4 or 5 mph in a parking garage. It happens pretty regularly when going that speed after a drive.
CT 200h noise: http://youtu.be/AU0RFW340xk
The noise can be heard when the car is slowing down, this one was me going maybe 4 or 5 mph in a parking garage. It happens pretty regularly when going that speed after a drive.
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03-11-15, 07:27 AM
#8
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i have that sound too. i think it's the regenerative brake system, but others can chime in. could very well be a pedestrian warning system too
Last edited by chroma23; 03-11-15 at 02:28 PM.
03-11-15, 08:47 PM
#9
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But if Jezo's CT is 2011, it would not have the Vehicle Proximity Notification system. They only start putting that in 2012 CT. I have a 2012 CT early year model and it doesn't have it.
That sound in the video does not sound like the regen brake. My regen brake gave a more continuous sound and higher pitch. The sound from the video is almost like the sound from anti-lock brake.
That sound in the video does not sound like the regen brake. My regen brake gave a more continuous sound and higher pitch. The sound from the video is almost like the sound from anti-lock brake.
03-12-15, 03:45 AM
#10
Driver
Thread Starter
03-23-15, 12:04 AM
#13
Lexus Test Driver
If it's a low moan as you come to a stop, then that's probably the traction motor doing regen braking. It can be a bit loud from the inside sometimes. The traction motor has a very high-pitched sound that's barely noticeable when you're driving on battery power or braking from high speeds.
04-07-15, 11:41 AM
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Currently have a CT loaner vehicle and I have to say this is the loudest and weirdest Lexus hybrid I have ever driven. As an RXh driver, I am used to the regenerative sound when braking. But the CT has a bunch of whirring, whizzing, clicking.
In addition to the regenerative braking noise
1) Brake pedal actually makes a "click" noise at the very first sign of being depressed
2) high pitched ringing, like that sound you get when you have ringing in your ears, all while the brake pedal is depressed
In addition to the regenerative braking noise
1) Brake pedal actually makes a "click" noise at the very first sign of being depressed
2) high pitched ringing, like that sound you get when you have ringing in your ears, all while the brake pedal is depressed