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Discussion Starter #1 (Edited by Moderator)
August 1st 2016
Last night I drove my volt while following behind a friend's vehicle. We came to a complete halt at a red light. During the time that we were stopped and my foot was still pressed on the brake pedal, the brakes suddenly felt mushy and the car began to move forward. I pushed the pedal harder with no response. The car actually sped up at this point, even though I had not taken my foot off the brake pedal. Finally I raised my foot up to reset the pedal travel and had to slam the brakes hard because the car had picked up even more speed as if I were pressing the gas! The brakes finally engaged but this was too late to prevent my car from ramming into the rear of my friend's car.
This was a very frightening incident for me.

The last time I had the vehicle serviced, it was kept at the dealership for extra days because of electrical and software issues.

I'm guessing there is a connection here.
 

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Ah, right .. the car all by itself accelerated from a dead stop, you didn't try to engage the parking brake, or shift it out of drive, but instead had "ramming speed" to your "friend"

Thank you for the warning.
 

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You have made a very serious allegation.

If true, you'll make the headlines.

In the past, many people who makes similar claims ended up proven wrong when the investigator reviewed the black box data - I am not at all saying this case is like that.

No judgement here, but if you strongly believe there is a real malfunction, call GM directly ASAP. These types of claims are taken very seriously.
 

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Did the police respond? Were you issued a ticket and are they investigating? Have you contacted GM.
 

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Bravo Sierra!
 

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Do you have a picture of your Volt? Sounds like there must have been some serious damage when your car rammed into your friend's car.

How far were you stopped behind him? It seems strange that there was enough time for this frightening sequence of events to unfold.
 

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Do you have a picture of your Volt? Sounds like there must have been some serious damage when your car rammed into your friend's car.

How far were you stopped behind him? It seems strange that there was enough time for this frightening sequence of events to unfold.
Won't be pictures for a while. Brand new user. 1 post.
 

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I don't want to be crude, but it seems this story is fabricated. It looks more like the guy was too drunk to know which pedal was which and accelerate into his friend but. Excuse me, his friend cars' but.
 

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The brakes on the Volt can always operate manually so electronic failures would not prevent braking.
 

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Seems to me that if my Volt had come to a complete stop behind a friend’s car at a red light, and the brake pedal I was pressing with my foot suddenly went all mushy, and then my car suddenly started moving forward while I pressed the brake harder, and then sped up even though I still had my foot on the brake, and while moving toward my friend’s stopped car I had time to raise my foot and put it down on the brake again as my car continued to accelerate (because I had originally stopped far enough behind my friend for this all to happen), and the brakes then worked and my car stopped but not before I had hit my friend’s car...

...my first thought wouldn’t be to get home and join a Volt forum and make my first post to tell other Volt owners that I had been stopped at a red light, when my car suddenly decided to surge ahead and hit the car in front of me...
 

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I have had a similar situation with my 2013 Volt. After driving on cruise control, when I start to apply the brakes to come to a stop, the car will accelerate for about 1 second. If I take my foot off the brake and then reapply the brakes, the car comes to a stop normally. This situation has occurred on icy roads and it gets a bit disconcerting when the car starts to accelerate when I want it to stop. It only seems to occur when coming off cruise control.
 

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I have had a similar situation with my 2013 Volt. After driving on cruise control, when I start to apply the brakes to come to a stop, the car will accelerate for about 1 second. If I take my foot off the brake and then reapply the brakes, the car comes to a stop normally. This situation has occurred on icy roads and it gets a bit disconcerting when the car starts to accelerate when I want it to stop. It only seems to occur when coming off cruise control.
From your Owner's Manual:

Warning

Cruise control can be dangerous on slippery roads. On such roads, fast changes in tire traction can cause excessive wheel slip, and you could lose control. Do not use cruise control on slippery roads.
 

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And/or slippery roads mean traction control kicks in which can feel like acceleration as even the minor amount of D regen turns off momentarily while the traction control is moderating the friction brakes to keep the wheels turning. "Icy roads" take all the bets off the table.
 

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And/or slippery roads mean traction control kicks in which can feel like acceleration as even the minor amount of D regen turns off momentarily while the traction control is moderating the friction brakes to keep the wheels turning. "Icy roads" take all the bets off the table.
Yes, the momentary loss of regen when someone's regen kicks out while hitting a pothole, bump, and the like can feel as if the car is "accelerating".

To to OP's situation count me on the dubious side given that the Volt has two brake methods, the electronic (power-assist) primary and a "4 wheel push through" failsafe mode. As DonC pointed out, even if the primary power-assist fails, the manual, mechanical system will still work. Without the power-assist, this means you have to press HARD on the brakes, but the brakes will work. This is how cars used to work before power assist became standard. I suspect the driver felt the loss of power-assist as a loss of brakes and was not pushing the brake pedal far or hard enough for part of the time.

See this post about the "4 wheel push through" failsafe mode: http://gm-volt.com/forum/showthread.php?157753-Brakes-failed-backing-up&p=2210969#post2210969
 

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We all experienced this when hitting a pothole or bumps while braking at low speed ("Low Traction" message appears in the DIC).
When this happends, we all have the "feel" the car is accelerating but in fact, it's not accelerating, just the regen braking deactivates 1 or 2 seconds. When I've done several efforts to reproduce the problem, my results were : I wasn't accelerating, and not braking, just lost regen braking that's all but we definitely "feel like accelerating" but in fact just loosing braking force. At this moment you can depress the pedal with a little more effort and you have hydraulic braking. But 1-2 seconds later regen braking reactivates. On icy roads this gives the feeling the braking force suddenly "doubles" when regen braking comes back, giving an uncomfortable braking for your passengers same as if you have slammed the brake pedal because the 2 braking systems are now working back together. It's not a problem. This is how regen braking in hybrids works (Prius, etc..)

The only thing to do : Keep a good distance with the other vehicles.
You were following your friend too close.
 
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