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Applying Pressure On The Brake Makes A Humming Noise Also Related to AUTO HOLD
I have noticed something that makes me believe that I should tell you about. Well, it only occurs when I engage auto HOLD when the tranny is in D . I hear a static buzzing sound . Do you also notice a weird noise when you engage HOLD in your car ? Should I worry or is it normal ?
My car has just turned 100K miles. I don't remember my first W212 had a noise when I took similar actions while waiting (I mean activating HOLD function )
Zero extra sound on HOLD, yes.
Use your scanner and see tranny torque output when in neutral , braking and HOLD.
As I recalled, tranny power output while in HOLD is the same as Neutral.
V12,
Try to do this :
Open hood, driver door open, engage D and allow car to move and do brake HOLD.
And then listen to the ESP / ABS pump. Is that the noise source. I was thinking if that pump is the one doing the actual HOLD for us.
Having a 2nd person is safer though
Thank you all for your valuable replies, I appreciate it a lot
I said the noise was about the HOLD, but it looks like when I put my foot on the brake while the car is in D (without engaging HOLD) , I also hear a same type of sound which makes me believe that it's coming from pump.
I have noticed something that makes me believe that I should tell you about. Well, it only occurs when I engage auto HOLD when the tranny is in D . I hear a static buzzing sound . Do you also notice a weird noise when you engage HOLD in your car ? Should I worry or is it normal ?
My car has just turned 100K miles. I don't remember my first W212 had a noise when I took similar actions while waiting (I mean activating HOLD function )
Originally Posted by konigstiger
Although OP realized noise is not associated with HOLD thought it best to mention the ESP CU controls the HOLD function.
I am not sure if this is related and therefore might also be considered not normal.
This is a completely different car, a 2017 W205 C 43, when I gently press on the brake there is no buzzing but when I put more pressure there is a buzzing static noise in a way I think it is similar to how you experienced or described it coming in the overhead area (so where the sunglass holder and dome lights area, not from the mirror not fully sure if that is indeed where the noise is coming from).
The noise is the loudest when DISTRONIC is active and when DISTRONIC brakes the vehicle to a stand still, noise completely gone when the vehicle is moving, noise is completely gone when stationary as long as parking brake is engaged. Disengage the parking brake and the noise is back regardless if vehicle is in Park, Neutral, Reverse or Drive when braking.
Without DISTRONIC engaged at all, noise is still there when increasing brake pressure on a stand still but way lesser than with DISTRONIC.
I wonder what it could be then?
The noise is also louder the warmer the ambient temperature is I think.
OP, if you don't mind me asking, does yours make a noise when simply pressing on the brake harder than just tapping it and does it also get louder when DISTRONIC is engaged? What about if you engage the parking brake, does it change the frequency or the loudness of the noise? Thanks : )
OP, if you don't mind me asking, does yours make a noise when simply pressing on the brake harder than just tapping it and does it also get louder when DISTRONIC is engaged? What about if you engage the parking brake, does it change the frequency or the loudness of the noise? Thanks : )
Thanks for your question
Well, I have observed that it makes a noise when I put my foot on the brake rather than pressing harder than usual . It does also make a same noise when I shift it out of P to D . My car didn't have DISTRONIC so I can't make a comment on it , sorry . Honestly, I have not been using parking brake quite a lot but when I use it , it makes a a different noise which is quite normal because it just makes its job , ( a mechanical grinding to halt sound , my first W212 also had it )
I think I have to edit the title of this topic
I said the noise was about the HOLD, but it looks like when I put my foot on the brake while the car is in D (without engaging HOLD) , I also hear a same type of sound which makes me believe that it's coming from pump.
Without knowing model or model year check if noise coming from hydraulic unit or brake booster area. @ 100,000 + wondering if simply bleeding system will help anyway see attached docs that may assist.
Thanks for your question
Well, I have observed that it makes a noise when I put my foot on the brake rather than pressing harder than usual . It does also make a same noise when I shift it out of P to D . My car didn't have DISTRONIC so I can't make a comment on it , sorry . Honestly, I have not been using parking brake quite a lot but when I use it , it makes a a different noise which is quite normal because it just makes its job , ( a mechanical grinding to halt sound , my first W212 also had it )
I think I have to edit the title of this topic
Thanks for your answer : ) I see, ya we are talking about a different type of sound then.
Yup, I understand what you are talking about in terms of the parking brake noise yup that is completely normal on your car.
Thing about my noise is I don't have to be on the brake when stationary for it to be apparent, as long as the vehicle is stationary, vehicle in park the noise is there, noise is gone when parking brake is engaged, noise is just louder when brake is depressed.
I do wish you good luck in getting it resolved though : )
Does the noise get louder when you open the windows, as in, is the sound coming from the outside?
Without knowing model or model year check if noise coming from hydraulic unit or brake booster area. @ 100,000 + wondering if simply bleeding system will help anyway see attached docs that may assist.
Thanks konigstiger, you are always helpful , I do really appreciate your posts
Originally Posted by W205C43PFL
Thanks for your answer : ) I see, ya we are talking about a different type of sound then.
Yup, I understand what you are talking about in terms of the parking brake noise yup that is completely normal on your car.
Thing about my noise is I don't have to be on the brake when stationary for it to be apparent, as long as the vehicle is stationary, vehicle in park the noise is there, noise is gone when parking brake is engaged, noise is just louder when brake is depressed.
I do wish you good luck in getting it resolved though : )
Does the noise get louder when you open the windows, as in, is the sound coming from the outside?
Thanks for your contribution as well . Well, the noise level is same I can hear it without opening the windows . I don't think that's a big deal but I will have it checked surely
Thanks konigstiger, you are always helpful , I do really appreciate your posts
Thanks for your contribution as well . Well, the noise level is same I can hear it without opening the windows . I don't think that's a big deal but I will have it checked surely
You're welcome and sounds good, keep us updated : )
Thinking way outside the box here... Try turning off your COMAND system completely, to see if electrical interference is a factor in the buzz. Climate control, too.
Thinking way outside the box here... Try turning off your COMAND system completely, to see if electrical interference is a factor in the buzz. Climate control, too.
Thanks again , I have noticed that when I hear that strange noise I also feel small vibrations on the brake pedal if I put my foot on the brake and when the car is stationary .This is why I already said it was related to AUTO HOLD because it also basically makes the same thing as if I put my foot on the brake pedal . I will have to edit the title
Thanks again , I have noticed that when I hear that strange noise I also feel small vibrations on the brake pedal if I put my foot on the brake and when the car is stationary .This is why I already said it was related to AUTO HOLD because it also basically makes the same thing as if I put my foot on the brake pedal . I will have to edit the title
Certainly does sound like ABS, for example ABS pulsating and pumping the brakes to help you stop when you lose traction for example.
UPDATE :
Engine mount as well as transmission mounts were worn out and needed to be replaced and those also make vibrations . Brake system was renewed as well such as brake discs , brake pads , brake calipers .
Thanks again for everyone , if the problem persists I will let you know as well
UPDATE :
Engine mount as well as transmission mounts were worn out and needed to be replaced and those also make vibrations . Brake system was renewed as well such as brake discs , brake pads , brake calipers .
Thanks again for everyone , if the problem persists I will let you know as well
Glad to hear it was resolved, what mileage is on your vehicle when all 3 mounts failed?
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