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Discussion Starter #1
My car (2015 500e) has a vibration in the brake pedal at almost every stop or near stop situation. If I turn on the car and step on the brake to shift into drive it starts vibrating then and continues for 2-3 seconds. Same experience if I'm driving very slowly or coming to a stop. Its interesting that even when I let off the pedal it continues for a couple seconds. It sounds and feels exactly like ABS engaging but is not related to a low traction situation. It has happened since I bought the car. It hasn't changed or gotten worse in anyway I just find it more and more annoying and worry that I'm wearing out the ABS actuators by allowing it to continue, if that is in fact what I'm feeling. Does anybody else have this experience? Is this a known issue or just a trait on all of these cars? Any insight would be appreciated.
Thanks!
 

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Discussion Starter #3
I'm fairly familiar with warped rotors. I have experienced that before. This is a much higher frequency vibration and occurs even when stopped. It could be described as a buzzing. The sensation I'm used too with warped rotors I would describe as a shaking. I may not have described it very well. Perhaps you know something that I don't though. Could warped rotors cause what I'm describing or is it just that I didn't describe it well?
 

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Discussion Starter #5
Yeah I'm planning to. Just hoping to get some input from other owners to get a base line of info to work with.
 

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I just went to the dealer this month for the same thing (2015 500e that hit 40k miles today). I can be completely stopped and the brake pedal will vibrate for a couple seconds where it feels like the ABS is engaged and the car also makes an audible buzzing noise. The dealer said it was normal and part of the regenerative system but it still seems weird to me. It hasn't been getting any worse at least and has been happening since I bought it 3 months ago at 37k miles.

Let us know if you get any answers.

(I also had the dealer immediately say my brake rotors must be warped until I described that it happens while completely stopped).
 

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Are you sure you aren't just feeling / hearing the brake assist charge pump? It sounds very similar to an ABS pump and actually operates nearly the same, except it's building up pressure in a hydraulic accumulator.

At a stop, in park with the car On / READY, press the brake pedal several times. You should feel / hear the charge pump run.

-J
 

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Discussion Starter #8
No, I'm not sure that it isn't the assist pump. I never considered that but it would make since, obviously the car makes no vacuum on its own... I'll look into this tonight. I will say if this is how the car is supposed to work I'm a little disappointed. It's the loudest feature on the car and feels clunky compared to every thing else on this very smooth car. Also I'd like to hear from more owners. If this is the design then everyone else should be experiencing the same thing.
 

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Discussion Starter #9
Update:
I'm thinking this is the pump. Thanks for the advice J. I pumped the brakes repeatedly while stopped in park and also did various other braking tests in parking lots and low traffic roads. My conclusion- it does it regularly at all speeds every third or fourth press of the brake pedal. It's just nearly undetectable at speed because of the normal road noise and vibration typical with braking from speed. I guess the only real remaining question is, does this racket point to an issue with the pump or is it typical to the 500Es? This is the only one I have ever driven so I don't have anything to compare to. It's encouraging to have your example Nolij though the dealership saying it's part of the regen system is kind of misleading.
 

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It sounds and feels exactly like ABS engaging
A faint buzzing and very small vibration from the hydraulic brake pump is normal in a 500e. However based on your description, it is much stronger and louder in your car than typical. I'm on my second 500e (both new leases), and the buzzing in both is unobtrusive enough that I don't notice it unless I'm paying attention to it. It is certainly nowhere near the level of ABS.
 

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...based on your description, it is much stronger and louder in your car than typical. I'm on my second 500e (both new leases), and the buzzing in both is unobtrusive enough that I don't notice it unless I'm paying attention to it. It is certainly nowhere near the level of ABS.
I agree, having driven 5 eFiats with zero to 30k mi. The issue seems rather similar to one I had right after charging at an "infected" public charger. It was corrected by disconnecting the negative 12V batt terminal for 30 seconds.
 

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Discussion Starter #13
...based on your description, it is much stronger and louder in your car than typical. I'm on my second 500e (both new leases), and the buzzing in both is unobtrusive enough that I don't notice it unless I'm paying attention to it. It is certainly nowhere near the level of ABS.
I agree, having driven 5 eFiats with zero to 30k mi. The issue seems rather similar to one I had right after charging at an "infected" public charger. It was corrected by disconnecting the negative 12V batt terminal for 30 seconds.
This comment intrigues me. Any more info on this issue you had? What were the symptoms?
Also I want to clarify the ABS comparison. I'm not saying it is like EARLY ABS where the whole car shook and the pedal refused to go down. I would park the car immediately if it were like that. Modern ABS tends to be slightly annoying rather than terrifying. That's what I'm comparing this to.
 

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I guess it must be the brake assist pump on mine too. Pressing the pedal a couple times while stopped makes it buzz.

Found this thread from 2015 so at least we're not alone. Apparently I haven't posted enough here to share links but the url is this website /forum/66-fiat-500e/84273-pulsing-vibration-when-brake-pedal.html
 

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It only happened once, momentarily (cuz I fixed it) quite a while ago. I only recall that it happened at low speed, I think ONLY below 6 or 7mph when the mech brakes take over from the regen.

It was a sort of scraping grinding sound like completely worn-off brake pads, but to me it somehow felt electronic, not mechanical, which is why I tried the cold reboot. Here's my original post:

https://www.fiat500owners.com/#/topics/145705
 

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Also I want to clarify the ABS comparison. I'm not saying it is like EARLY ABS where the whole car shook and the pedal refused to go down. I would park the car immediately if it were like that. Modern ABS tends to be slightly annoying rather than terrifying. That's what I'm comparing this to.
I've experienced ABS on the 500e while braking downhill on a wet street, and the pump buzzing/vibration isn't at all like ABS on either of the two 500e I've leased. The buzzing I hear is faint and not noticeable with ambient noise, e.g. radio at very low volume. The vibration at the brake pedal is subtle and I feel it only while the car is stationary. I think the brake pump noise and vibration in your 500e are probably more pronounced than average.
 

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Discussion Starter #19
I'll give this a try tonight. Your description is different than mine but I've got nothing to loose pulling the battery terminal. I should mention that the noise may be more pronounced on my car than others because the pedestrian buzzer is not functional on mine.
 

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I removed my silly pedestrian buzzer long before this. Lots of EVs don't have one, a coasting ICE doesn't have one, & neither does the bicycle that I spend more time riding than my car.

I must admit to having difficulty accurately describing the sound/feel, even when it was fresh in my mind. In my defense, I was very shocked by it AND also running late for work at the time!

Please let us know if the 30-second 12V disconnect works.
 
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