Chevy Bolt EV Forum banner

1 - 20 of 43 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Test drove a 39k LT model. 2 blocks from the dealer lot a low battery warning came on. Prompted us to switch to power saver mode. Dash said it had a range of 193 miles. I commented on that as the sales person switched it to power saver mode. As we rolled up to a red light the car started pulsing and would not stop. It slowed, but would not stop. Sales guy yells at me to stop and I'm standing on the brake pedal as we start rolling into the intersection with cars driving through. Sales guy turns the car off and it stops.

Re-started the car and everything seemed fine. But would not go into gear. Kept giving error. Something about incorrect state to use shifter...

With a vette a burb and a sonic at my house I was of course looking to see what chevy had in the EV arena.

Below 2 sales guys looking at the car where it sat unable to move.

Bolt 1.jpg

Bolt 2.jpg
 

·
Registered
Joined
·
204 Posts
Holy moly! I'll bet that salesman had to change his shorts. Please let us know if you find out the resolution to this "issue." I know it's not your car, but the entire community could learn a lot from your follow-up. Glad you weren't hurt.
 

·
Registered
Joined
·
1,486 Posts
Glad they were able to turn it off in time, can't imagine how scary that situation was for you. Hopefully that won'y turn you away from the Bolt, even though it seems like their tester car needs a bit of fixing.
 

·
Registered
Joined
·
624 Posts
aren't the brakes hydraulically linked to the brake pedal? so even if all the software/assist isn't working, the brake pedal should still stop you. something is seriously wrong with that car.
 

·
Registered
Joined
·
195 Posts
:eek:I've been following the Bolt since release. NEVER heard anything similar. Glad everyone is OK.
 

·
Registered
Joined
·
112 Posts
Cars that are predominately computer controlled certainly have the potential for some interesting bugs/failure modes.

The Bolt has two batteries, the big battery pack and the little 12V battery. If the little 12V battery is low then odd things can happen. With cars sitting on the dealer lot it is quite possible for the 12V battery to get discharged to the point that it isn't providing the proper power to the onboard computer and other components that run off the 12V battery.

The level of charge in the big battery pack is pretty much irrelevant to the operation of anything except the drive motor.

I had a Spark EV that drove fine to a restaurant but when leaving it turned on, the headlights came on but it wouldn't go into drive, it wouldn't shut off and even the headlights couldn't be shut off. A low/defective 12V battery was the diagnosed cause.

It is disturbing that the mechanical brakes appeared to be inoperative in your case. Certainly seems to be a failure mode that should be reported to the NHTSA:

https://www-odi.nhtsa.dot.gov/VehicleComplaint/
 

·
Registered
Joined
·
1,931 Posts
Parking brake should have still worked, Bolt owners with a few miles under their belts probably would have tried that.
 

·
Registered
Joined
·
112 Posts
aren't the brakes hydraulically linked to the brake pedal? so even if all the software/assist isn't working, the brake pedal should still stop you. something is seriously wrong with that car.
The mixed regenerative/mechanical braking system has at least some computer control. ABS braking involves some electronic component being able to remove the braking force even while you have the brake pedal fully engaged.

It would be an interesting test to put your Bolt on a flat street, disengage the parking brake, disconnect the 12V battery and have some friends push your Bolt and see if the mechanical brakes engage when you press the brake pedal.
 

·
Registered
Joined
·
862 Posts
Doesn't this sound like one of the battery failures GM has talked about?
193 miles range remaining, but car dies while driving.

No offense to the OP, but the rest sounds very similar to hitting the accelerator instead of the brake (with a dead/nearly dead car due to a HV battery failure).

I wasn't there, don't know, no accusations, just my thoughts.
 

·
Registered
Joined
·
112 Posts
Doesn't this sound like one of the battery failures GM has talked about?
193 miles range remaining, but car dies while driving.

No offense to the OP, but the rest sounds very similar to hitting the accelerator instead of the brake (with a dead/nearly dead car due to a HV battery failure).

I wasn't there, don't know, no accusations, just my thoughts.
"Pulsing", "slowed but wouldn't stop" doesn't sound like hitting the accelerator by mistake.

People who mash the accelerator on the Bolt get a pretty different experience, though I admit I haven't done that in low power mode.
 

·
Registered
Joined
·
862 Posts
"Pulsing", "slowed but wouldn't stop" doesn't sound like hitting the accelerator by mistake.

People who mash the accelerator on the Bolt get a pretty different experience, though I admit I haven't done that in low power mode.
This was just before the car went into complete failure mode and wouldn't move at all.

It quickly went from normal to low power to nada. I agree that mashing the accelerator of a correctly functioning Bolt would not have the OP's reported result. But he may have gotten the last little bursts of energy the car was willing to provide as the electronics/battery failed and the described behavior is consistent with that theory.

People who have been driving their cars for a long time have hit the wrong pedal, then mashed it when the car didn't slow. Doing so on a test drive of an unfamiliar vehicle that starts acting erratically is plausible.

http://jalopnik.com/weird-tesla-crash-was-result-of-wrong-pedal-press-witn-1604626367
https://electrek.files.wordpress.com/2016/09/tesla-gym-crash-pic-3.png?w=2000&h=1000#038;h=494

Many more examples can be found
 

·
Registered
Joined
·
112 Posts
Hope we learn more about this particular failure.

GM had said the problem with faulty SOC readings was on early production models and was supposed to have identified them for replacement of the battery pack. The experience of one person who suffered this failure was:

"On that Tuesday afternoon, the dashboard indicated approximately 100 miles of remaining range. (Because I was less than one mile away from home, I did not take note of the exact state of charge.) After a few seconds of a warning chime, the steering wheel shuddered, and the vehicle quickly came to a complete stop in the middle of the road. When I looked down at the dashboard, the indicated remaining range had abruptly changed to nine miles."

Perhaps OP can comment on whether his failure was similar
 

·
Super Moderator
Joined
·
2,564 Posts
Cars that are predominately computer controlled certainly have the potential for some interesting bugs/failure modes.
Yes they do and I'm sure we'll be seeing some very interesting and possibly terrifying ways they can fail in the future from all manufacturers. Particularly those that are rushing for 100% autonomous driving.

This scene right here-



...just set EVs, and Chevrolet back about ten years in perception of EVs and GM by everyone that drove by and witnessed it. In addition, how much do you think those sales people will now promote the Bolt? This event just confirms people's biases and prejudices that BEVs aren't ready for prime time and GM still makes crappy cars. :( Sad.
 

·
Registered
Joined
·
112 Posts
Fortunately 95% of the people who drove by the Bolt probably didn't realize it was an EV and since it wasn't on fire it probably barely registered at all. Of that 5% that knew it was an EV, 3/4ths of the people they tell the story to will think they said a Chevy Volt was the broken down car.

No question that it is still the early days of the computerization of cars and there is still lots to learn on how to make them fail safe, fail less and detect pending failures better.
 

·
Registered
Joined
·
204 Posts
I'm used to driving cars with two separate hydraulic brake circuits plus a mechanical parking brake for backup.

It's upsetting to think that GM would design a vehicle where one of the "failure modes" is the total absence of any way to stop the car.

Is the lesson here to always remember to hit the power button if the brake pedal has no effect? :eek:
 

·
Super Moderator
Joined
·
2,564 Posts
I'm used to driving cars with two separate hydraulic brake circuits plus a mechanical parking brake for backup.

It's upsetting to think that GM would design a vehicle where one of the "failure modes" is the total absence of any way to stop the car.

Is the lesson here to always remember to hit the power button if the brake pedal has no effect? :eek:
The problem is the ABS/Stability control. This system allows the computer to activate servos to override the hydraulic brakes. Not just the Bolt. Pretty much every modern car. In this case it sounds like there was un-commanded throttle input and that put the motor fighting the brakes. For whatever reason, the ABS kicked in to help relieve the stress I guess. That explains the pulsing and creeping forward.

In this case, the parking brake would have been of no use IMO. Shifting to neutral or Park might have worked, but all those things are computer controlled so who knows if it would have helped.

The big off button was probably the best choice. If that hadn't worked, I guess you would have to let it keep creeping until you could get it up against a wall and then get out and watch the sparks fly! :eek: Could be pretty scary! I hope it never comes to that for anybody.

Would love to hear from GM about this but probably won't... other than a possible recall notice. This sounds very much to be a safety issue even greater than the ignition switch thing.
 

·
Registered
Joined
·
1,494 Posts
I think the "nearly dead" 12V battery is the likely culprit. Just enough to start it, not enough to sustain it. I hope it is a simple fix and I look forward to the follow-up.
 
1 - 20 of 43 Posts
Top