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Rarely, while braking, and the car is approaching ~ 5mph to ~ 10mph speed range, I get a sudden brief acceleration, less than 1 second, but definitely acceleration. It is unnerving.
The first few times I thought my foot had slipped off the brake and hit the accelerator.
After more experience with the issue, this is definitely not the cause.
It happens maybe once every other trip, usually at low speed, when approaching a stop light for instance.
Some may call this unexpected 'lurching' during braking.

It may be related to the regenerative braking system. However, I would expect a loss of braking power, not acceleration, if this was the case.
Yes it is actual acceleration, positive dV/dt, not loss of braking that I feel.

I found some folks experienced similar issues but most seemed to feel it was a loss of braking

It is unlikely that I am going to take it in to dealer, as it is an intermittent issue and likely no problems will be found.

Anyone experience similar?

Thanks
Thanks to whoever bumped this thread up. I thought it was just me. I brake early and come up to stop signs slowly. And multiple times a day, the car gently lunges forward when it should be slowing down to 0. Freaks me out. Doesn't happen when I brake harder.
 

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Thanks to whoever bumped this thread up. I thought it was just me. I brake early and come up to stop signs slowly. And multiple times a day, the car gently lunges forward when it should be slowing down to 0. Freaks me out. Doesn't happen when I brake harder.
once again, are you sure it is acceleration, and not decreased deceleration? Decreased deceleration is what I experience.
 

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once again, are you sure it is acceleration, and not decreased deceleration? Decreased deceleration is what I experience.
Pretty sure. If I released my brakes at that slow speed, the car won't lunge forward, it will just coast.

I've driven a Clarity PHEV for the past 3 years with regenerative braking. Never experienced this before.
 

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Pretty sure. If I released my brakes at that slow speed, the car won't lunge forward, it will just coast.

I've driven a Clarity PHEV for the past 3 years with regenerative braking. Never experienced this before.
yes, but your body is used to the deceleration force, and when that decreases unexpectedly it can feel like acceleration. The real question is if the speedometer goes up, not down, during this event.
 

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yes, but your body is used to the deceleration force, and when that decreases unexpectedly it can feel like acceleration. The real question is if the speedometer goes up, not down, during this event.
Yeah, it’s just decreased deceleration caused by a quirk in the way the blending is done between the regenerative brakes and the friction brakes. You can simulate the feeling by lightly braking and before coming to a stop switch the selector from D to N. You get the same feeling of ‘acceleration’ which is actually just decreased deceleration.
 

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Yeah, it’s just decreased deceleration caused by a quirk in the way the blending is done between the regenerative brakes and the friction brakes. You can simulate the feeling by lightly braking and before coming to a stop switch the selector from D to N. You get the same feeling of ‘acceleration’ which is actually just decreased deceleration.
That's my take, but others here have claimed an acceleration even after going over this aspect.
 

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That's my take, but others here have claimed an acceleration even after going over this aspect.
I would not be so sure of myself had I not experienced the exact same thing on several occasions. And no proof has been given as far as seeing speed increase or seeing the power meter go into the positive range. So I’m sticking with decreased deceleration.
 

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Thanks to whoever bumped this thread up. I thought it was just me. I brake early and come up to stop signs slowly. And multiple times a day, the car gently lunges forward when it should be slowing down to 0. Freaks me out. Doesn't happen when I brake harder.
I have plowed through this thread re brakes. My story is similar to others re the low speed brake subject. Slowly approaching vehicles stopped ahead at red light, and brakes go "soft", I lift foot off pedal, reapply and it engages as one expects. It happens once or twice every couple of months, and agree, it is frightening. I have experienced this since ownership of my June 2018 Hybrid.

I can also add a more frightening circumstance that has occurred 3x in last month. Highway speed driving for over 2.5 hrs. and decelerated at exit lane. As I approached a stop point, I hit brakes, they engaged, then soft, then vehicle accelerated as I used ALL my ability to press hard on brake. I am not a two foot driver. I steered slightly left as I thought I would hit vehicle ahead, but I did not. Stopped successfully, started driving forward again when traffic moved along and no issue. Tried a few starts and stops and no issues.

I am trying to describe best I can, re acceleration incidents. Cruise function was not on. There was also a grinding sound, similar to my few experiences with my old ford windstar van, when "xxx" brakes engaged travelling on ice.
("xxx" - can't recall brake adjective)

I have not had any other service issues, other than recall repairs. While I am completely satisfied with dealer from purchase day to present, like others, the brake situ can't be duplicated. They have checked for rust and inspected callipers, pads rotors etc. My ride is perfect in all other ways. Is this brake subject matter on another thread? 45+ posts does not seem enough.

Anyone know if there is some sort of onboard recorder/monitor a dealer can install? I could always make note of milage whenever incident occurs. Thanks in advance for any advice
RAP
 

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[QUOTE="RAP, post: 594793, member: 62752]

As I approached a stop point, I hit brakes, they engaged, then soft, then vehicle accelerated as I used ALL my ability to press hard on brake. I am not a two foot driver. I steered slightly left as I thought I would hit vehicle ahead, but I did not. Stopped successfully, started driving forward again
[/QUOTE]
So let me get this straight. You hit the brakes and they engaged (so you must have been decelerating). Then the brakes went soft. Then you started accelerating (acceleration is when the rate of speed increases over time). And then you stopped. As an example, you were going 50 mph, you brakes, the car slowed down to 30 mph, then for some reason it sped back up to 35 mph, and then you slowed down again to eventually come to a stop.
 

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[QUOTE="RAP, post: 594793, member: 62752]

As I approached a stop point, I hit brakes, they engaged, then soft, then vehicle accelerated as I used ALL my ability to press hard on brake. I am not a two foot driver. I steered slightly left as I thought I would hit vehicle ahead, but I did not. Stopped successfully, started driving forward again
So let me get this straight. You hit the brakes and they engaged (so you must have been decelerating). Then the brakes went soft. Then you started accelerating (acceleration is when the rate of speed increases over time). And then you stopped. As an example, you were going 50 mph, you brakes, the car slowed down to 30 mph, then for some reason it sped back up to 35 mph, and then you slowed down again to eventually come to a stop.
[/QUOTE]
Basically correct. I can't say that my speed actually increased, but the engine rev was increasing, it wanted to take off on me. That is why I was pressing so hard on brake pedal.
 

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So this doesn't only happen at very low speeds like 5mph. I've experienced it at between 15-10mph also. I've also started braking, kept my foot steady on the brakes, and switch the gear to neutral. Not the same feeling at all. Seems this van does not like early breaking. I do notice a noise, so I think the guys are correct here. Something happening with the brakes switching over.

When this first happened, and I didn't come upon this thread, I was wondering if I had drum brakes. It's been a while, but I seem to remember having to depress the brakes harder back then.
 

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I am wondering if the instances of people having the increased speeds correspond to the engine turning on while braking. I don't think I have ever had that scenario, and I would think it would be rare due to the typical mode of operations. But it may explain a few things.
 

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Discussion Starter #74
Once again it ACCELERATION, NOT LOSS OF BRAKING that I (and apparently others) are experiencing.
Please stop insisting it is loss of braking.
If you don't experience acceleration while braking, then good for you.

For the few of us that do experience unintended acceleration while braking, it is unnerving.
Gas Engine does not turn on.

not this ---> "decreased deceleration caused by a quirk in the way the blending is done between the regenerative brakes and the friction brakes" <---- not this

For me this is an ongoing issue

Did I mention that this is NOT "decreased deceleration"
 

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I am wondering if the instances of people having the increased speeds correspond to the engine turning on while braking. I don't think I have ever had that scenario, and I would think it would be rare due to the typical mode of operations. But it may explain a few things.
Yeah, that is interesting. I would never expect the engine to be running when decelerating from highway speeds on an exit ramp. Once I let off the gas in such a situation it’s a pretty short amount of time before the ICE shuts off.
 

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Yeah, that is interesting. I would never expect the engine to be running when decelerating from highway speeds on an exit ramp. Once I let off the gas in such a situation it’s a pretty short amount of time before the ICE shuts off.
I had one time in stop-go traffic where the engine kept coming on and off, and several times there was "wierdness".
 
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