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Discussion Starter #1
Hello folks,

We've now had the bolt for over 3 mo. Premier version. Close to 1500 mi. Love it. For the past few days, mrs. and I have noticed the car attempting to accelerate concerningly with increasing frequency. Happens both in L and D under normal driving conditions. Dry weather and roads. Happens when holding steady speed, while slowing down under regen, and also while trying to accelerate. We initially thought it was something on the road, but the increasing frequency has gotten us worried. I will take it to the dealership tomorrow. Has anyone experienced anything like this? All the stories from the past about disastrous unintended acceleration has us worried that there might be a hitherto undetected issue with the Bolt.
 

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Are you wearing your seat belt ? Make sure the floor mat or anything else is not interfering with the accelerator pedal.
 

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Happens when holding steady speed, while slowing down under regen, and also while trying to accelerate.
If a front wheel hits a bump and becomes momentarily airborne, it can trigger the traction control system. When that happens, the car will drop out of regen, which can feel like acceleration. This could potentially apply to all the situations you described if you're descending a steep hill and regen is preventing you from going faster than the speed you're commanding with the accelerator pedal.
 

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i had a similar experience last night. i had the cruise control on, driving on the freeway. i had braked, so the cruise wasn't currently active. but the car started accelerating as if i had hit the resume button.

i haven't been able to repeat it yet, but i'm keeping an eye out.
 

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Are you wearing your seat belt ? Make sure the floor mat or anything else is not interfering with the accelerator pedal.
Yes, wearing seat belt. The carpet was the first thing that crossed our mind. It appears to be secure. And its effect would not be so transient. The acceleration spikes come and go....almost a jumpy feeling when that happens.
 

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Yes, wearing seat belt. The carpet was the first thing that crossed our mind. It appears to be secure. And its effect would not be so transient. The acceleration spikes come and go....almost a jumpy feeling when that happens.
Do these spikes happen right after you hit a large bump?
 

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I get these when parking in L, when I nudge the accelerator it'll jump. This is why I switch to D for parking, as I can use the artificial creep to nudge forward.
 

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Take your shoe off and drive the car while paying attention to foot movement when this happens.
This throttle design has a fail safe and redundant safety features. I'm betting it the drivers foot.
 

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Take your shoe off and drive the car while paying attention to foot movement when this happens.
This throttle design has a fail safe and redundant safety features. I'm betting it the drivers foot.
Good suggestion. Will try that. Though it's odd that the problem appeared within the last couple of weeks and not before. Same driver and driving technique.
 

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Discussion Starter #14
Please be careful because in our case, we initially dismissed it as an aberration - we assumed that perhaps we'd hit the accelerator, or that the regen had momentarily disconnected and reconnected because maybe we hit a bump and did not realize it. However, off late, this is happening more frequently and I am hoping that either the onboard diagnostic is recording it, or, that the service guys are able to reproduce the issue.
 

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I sincerely hope GM learned from Toyota and didn't put the drive by wire function on a shared bus. If you have a "spammy" or malfunctioning CAN module, important stuff can and does get dropped. Ideally you implement a packet sequencing checksum that shuts down the drive system in the event of a bus malfunction blocking or dropping packets. Do you have your build date from the driver's door sticker? Also do you have anything plugged into the OBDII port on the car? GM has already had some module timing and communications issues for other systems in this car, which is (partly) why I bring it up.
 

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I sincerely hope GM learned from Toyota and didn't put the drive by wire function on a shared bus. If you have a "spammy" or malfunctioning CAN module, important stuff can and does get dropped. Ideally you implement a packet sequencing checksum that shuts down the drive system in the event of a bus malfunction blocking or dropping packets. Do you have your build date from the driver's door sticker? Also do you have anything plugged into the OBDII port on the car? GM has already had some module timing and communications issues for other systems in this car, which is (partly) why I bring it up.

This is a very common problem and most customers don't understand it. They never tell the
service dept. they're using one and wonder why we can't find their issue because they've removed
it when they brought the car in for service. These devices cause major problems with bus communications and will set lots of U code DTC's from timing issues.

If you use one and have problems, unplug it and see if the problem goes away. The MIL might
not turn off, but most of the time erratic issues will vanish like magic. :nerd:
 

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CAN bus sounds pretty crappy... why hasn't something more robust been implemented in vehicles? i say this without exaggeration, lives are on the line.
 

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I sincerely hope GM learned from Toyota and didn't put the drive by wire function on a shared bus. If you have a "spammy" or malfunctioning CAN module, important stuff can and does get dropped.
I'd be very surprised and disappointed if the critical throttle, brake and steering control systems could be compromised that way.
 

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CAN bus sounds pretty crappy... why hasn't something more robust been implemented in vehicles? i say this without exaggeration, lives are on the line.
Can Bus is a proven system and has been in most modern vehicles since 2008.
It's a module communication network. It's not designed to actually control components.
That's left to the control module and all systems have failsafe/defaults. The fly-by-wire
system will default to OFF whenever the system has problems. I have never heard of or know
of any issue with this system. Toyota's system wasn't the same at the time they had issues.
I think you have Toyota paranoia >:)

This system can disable engine starting if it detects a problem and that includes an EV :nerd:
While you are driving it can disable acceleration also known as limp mode.
 
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