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Discussion Starter · #1 ·
Hey guys I know I haven't been active here much lately but something interesting happened today I felt was worth sharing as kind of a PSA and a real world report of how emergency procedures operate in a real world situation.

Simple situation really, I was driving along on a local street at about 35MPH and just as I was passing a fire station the door comes up and a fire truck starts to emerge with it's lights on.

Not knowing which direction the fire truck was turning and wanting to get out of the way ASAP I just floored the accelerator for a few seconds.

The problem is that when I let off the accelerator the car kept accelerating, I'm now probably doing more than 60MPH on a thankfully empty street.

I firmly applied the brakes and the car did slow down quickly, probably got to about 20MPH and I let off the brake briefly and the car immediately started accelerating again.

As a quick aside, letting off the brake even briefly is not what you're supposed to go in this situation. The brakes in any modern vehicle are significantly stronger than the engine or motor but once the brakes overheat they can start to fade and you could find yourself without functional brakes. I was trying to troubleshoot the situation and since my speed wasn't that high and the road ahead was clear I had no problems bringing the car under control but I've heard stories of people who were in a car with a stuck accelerator and used the brakes to maintain their speed instead of stopping until the brakes failed completely. If you use the brakes in any kind of runaway vehicle situation you're supposed to firmly press and hold the brakes and decelerate down to a complete stop. You can only count on one or two good brake applications in a situation like this.

I quickly re-applied the brakes, kept them applied and simultaneously pressed and held the start/stop button all while pulling over to the side of the road. I got down to about 10MPH when the car finally turned off.

Now I was prepared to lose all power steering as well as brake assist when the car turned off but I still had good braking and steering until I finally came to a stop on the side of the road. Granted that was only about 10 seconds but still.

When I came to a stop the car wasn't completely powered down as I would have expected, instead the instrument cluster display just displayed the message "start vehicle to view application" and the infotainment screen was still working like normal (displaying Waze via Android Auto)

The doors remained locked until I pressed the Park button on the mode selector at which point the doors unlocked, the parking brake applied and presumably the gearbox engaged the parking pawl. This is also when the instrument cluster display powered down.

When I opened the door to check everything out I smelled the unmistakable odor of overcooked brakes but they absolutely did work exactly as I needed them to.

Inspecting the car I found that my floor mat (tux mats) had shifted forward a couple inches just enough to catch the accelerator pedal and preventing it from returning normally.

When I adjusted the floor mat and restarted the car everything worked just like normal.

I'm actually disappointed in the TuxMats that this was even possible. I guess that's the downside of the design that doesn't directly attach to the little studs installed in the floor specifically to secure the floor mat to prevent exactly this kind of situation. If you had asked me yesterday I would have told you I preferred the TuxMats to the WeatherTech mats I used to use but not anymore. Granted I haven't inspected these in the more than 3 years since I installed them but still I wouldn't have thought I needed to.

The main PSA part is if you have TuxMats or especially any kind of "generic" floor mat (not specifically designed for your car) to make sure they aren't in a position where they could interfere with the operation of the pedal. This can create a dangerous situation that can (and has) lead to a serious, even fatal accident.

The other is to be aware of the "Emergency Stop" procedure, which is as simple as pressing and holding the start/stop button on the car until the car (or at least the drive system) turns off. I always knew about this procedure (which I believe is universal for all cars that use push button start instead of a keyed ignition switch) but I did not know the level of control I'd have if I ever had to use it.
 

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Hey guys I know I haven't been active here much lately but something interesting happened today I felt was worth sharing as kind of a PSA and a real world report of how emergency procedures operate in a real world situation.

Simple situation really, I was driving along on a local street at about 35MPH and just as I was passing a fire station the door comes up and a fire truck starts to emerge with it's lights on.

Not knowing which direction the fire truck was turning and wanting to get out of the way ASAP I just floored the accelerator for a few seconds.

The problem is that when I let off the accelerator the car kept accelerating, I'm now probably doing more than 60MPH on a thankfully empty street.

I firmly applied the brakes and the car did slow down quickly, probably got to about 20MPH and I let off the brake briefly and the car immediately started accelerating again.

As a quick aside, letting off the brake even briefly is not what you're supposed to go in this situation. The brakes in any modern vehicle are significantly stronger than the engine or motor but once the brakes overheat they can start to fade and you could find yourself without functional brakes. I was trying to troubleshoot the situation and since my speed wasn't that high and the road ahead was clear I had no problems bringing the car under control but I've heard stories of people who were in a car with a stuck accelerator and used the brakes to maintain their speed instead of stopping until the brakes failed completely. If you use the brakes in any kind of runaway vehicle situation you're supposed to firmly press and hold the brakes and decelerate down to a complete stop. You can only count on one or two good brake applications in a situation like this.

I quickly re-applied the brakes, kept them applied and simultaneously pressed and held the start/stop button all while pulling over to the side of the road. I got down to about 10MPH when the car finally turned off.

Now I was prepared to lose all power steering as well as brake assist when the car turned off but I still had good braking and steering until I finally came to a stop on the side of the road. Granted that was only about 10 seconds but still.

When I came to a stop the car wasn't completely powered down as I would have expected, instead the instrument cluster display just displayed the message "start vehicle to view application" and the infotainment screen was still working like normal (displaying Waze via Android Auto)

The doors remained locked until I pressed the Park button on the mode selector at which point the doors unlocked, the parking brake applied and presumably the gearbox engaged the parking pawl. This is also when the instrument cluster display powered down.

When I opened the door to check everything out I smelled the unmistakable odor of overcooked brakes but they absolutely did work exactly as I needed them to.

Inspecting the car I found that my floor mat (tux mats) had shifted forward a couple inches just enough to catch the accelerator pedal and preventing it from returning normally.

When I adjusted the floor mat and restarted the car everything worked just like normal.

I'm actually disappointed in the TuxMats that this was even possible. I guess that's the downside of the design that doesn't directly attach to the little studs installed in the floor specifically to secure the floor mat to prevent exactly this kind of situation. If you had asked me yesterday I would have told you I preferred the TuxMats to the WeatherTech mats I used to use but not anymore. Granted I haven't inspected these in the more than 3 years since I installed them but still I wouldn't have thought I needed to.

The main PSA part is if you have TuxMats or especially any kind of "generic" floor mat (not specifically designed for your car) to make sure they aren't in a position where they could interfere with the operation of the pedal. This can create a dangerous situation that can (and has) lead to a serious, even fatal accident.

The other is to be aware of the "Emergency Stop" procedure, which is as simple as pressing and holding the start/stop button on the car until the car (or at least the drive system) turns off. I always knew about this procedure (which I believe is universal for all cars that use push button start instead of a keyed ignition switch) but I did not know the level of control I'd have if I ever had to use it.
Always good to let others know about potential safety problems. Glad you are safe!

This type of problem is something yo hear about occasionally with aftermarket floor mats. It even happens every once in a while with OEM mats.
 

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IMHO, they should mandate cars to use floor mounted accelerator pedal and clearly should have done so since the Toyota fiasco. It's why I only use factory floormats and simply replace them as needed, although I'm not in an area where I track in a lot of mud so that's easy for me.
 

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With manual transmission cars, a switch to disconnect the engine from the wheels is under your left foot.

In any car, you can shift to neutral (N) on the transmission selector.
Not the point. A kill switch stops the engine from runaway by killing ignition. If you push in the clutch or select neutral you stand a chance of the engine over-revving and throwing a rod etc.
 

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Thanks, I have Tux mats and will check it. The mats are great but the mounting system with side clips under the rubber molding and only one kinda shady pin through the mat in the middle leaves lots to be desired.
My driver side is also shifting getting in and out. I might just cut back the part under the accelerator with a razor knife to give more room.
Scary, sorry it happened but many thanks for the heads up.
 

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Discussion Starter · #9 ·
Not the point. A kill switch stops the engine from runaway by killing ignition. If you push in the clutch or select neutral you stand a chance of the engine over-revving and throwing a rod etc.
FWIW the only other time this has happened to me was about 30 years ago and I was in a manual transmission car. I did push in the clutch and at the same time turned off the ignition. Of course turning off the ignition in a keyed ignition vehicle (as in almost all cars without push button start) you have to be careful to not turn the key in such a way that you lock the steering column which could turn really bad really fast.
 

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FWIW the only other time this has happened to me was about 30 years ago and I was in a manual transmission car. I did push in the clutch and at the same time turned off the ignition. Of course turning off the ignition in a keyed ignition vehicle (as in almost all cars without push button start) you have to be careful to not turn the key in such a way that you lock the steering column which could turn really bad really fast.
Another reason for a kill switch. It will only turn off the engine, and without hurting it or anything else.
 

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Another reason for a kill switch. It will only turn off the engine, and without hurting it or anything else.
Many cars with drive-by-wire accelerators set accelerator input to zero (regardless of the accelerator position) if the brake is applied. Basically a "kill switch" that is activated by the natural reaction of stepping on the brake pedal (i.e. no need to remember how to use a rarely used separate kill switch). Does the Bolt do this?
 

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Glad you are ok and thanks so much for posting this gripping account. Thanks for posting the details on what to do ... and what not to do!

Again, it's great hearing from you again and super glad that had the peace of mind to get out of this very dangerous situation!
 

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It's scary enough that the floor mat can cause sudden acceleration (not just on the Bolt), but I'm still not clear about the best way to stop this on the Bolt. Pressing the Start/Stop button as mentioned here seemed to help, but I don't think that's as intuitive as slamming the brakes would be and I wonder if the power steering would go away and cause other safety issues if you turn off the car (at least that's what I remember if you turn off an ignition key)?

Regarding using the brakes, I've seen several topics about this here and I still don't see a clear conclusion. Some say it works and overrides the accelerator (or overpowers it), others say the brakes didn't work. Here's a few of the topics, including the one mentioned earlier here:

Chevrolet Premium Floor Liner and Stuck Accelerator Pedal

Accelerator issue?

Unintended Acceleration

800 Miles on 2019 Bolt EV and brake issue

So if you experience sudden acceleration on the Bolt for whatever reason, will hitting the brakes work? Putting the Bolt in neutral has also been discussed but I'm not clear on the conclusion for that either.

As most know, Toyota (and I assume other companies) had sudden acceleration issues several years ago. At first it seemed to be due to the floor mats, but then it morphed into a potential problem with electronic acceleration control (vs. manual control via cable) on newer cars at the time. In one of the early incidents a highway patrolman and his family were killed while he was talking to 911 and saying his car was going 120 mph and the brakes would not work on a Lexus. I thought that issue was fixed on later cars by disabling the accelerator if you hit the brakes.

Is there any agreement on the best way to stop a runaway Bolt?
 

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2020 Chevrolet Bolt
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It's scary enough that the floor mat can cause sudden acceleration (not just on the Bolt), but I'm still not clear about the best way to stop this on the Bolt. Pressing the Start/Stop button as mentioned here seemed to help, but I don't think that's as intuitive as slamming the brakes would be and I wonder if the power steering would go away and cause other safety issues if you turn off the car (at least that's what I remember if you turn off an ignition key)?

Regarding using the brakes, I've seen several topics about this here and I still don't see a clear conclusion. Some say it works and overrides the accelerator (or overpowers it), others say the brakes didn't work. Here's a few of the topics, including the one mentioned earlier here:

Chevrolet Premium Floor Liner and Stuck Accelerator Pedal

Accelerator issue?

Unintended Acceleration

800 Miles on 2019 Bolt EV and brake issue

So if you experience sudden acceleration on the Bolt for whatever reason, will hitting the brakes work? Putting the Bolt in neutral has also been discussed but I'm not clear on the conclusion for that either.

As most know, Toyota (and I assume other companies) had sudden acceleration issues several years ago. At first it seemed to be due to the floor mats, but then it morphed into a potential problem with electronic acceleration control (vs. manual control via cable) on newer cars at the time. In one of the early incidents a highway patrolman and his family were killed while he was talking to 911 and saying his car was going 120 mph and the brakes would not work on a Lexus. I thought that issue was fixed on later cars by disabling the accelerator if you hit the brakes.

Is there any agreement on the best way to stop a runaway Bolt?
My owner's manual (2020) says:
"If the vehicle must be shut off in an emergency:
1. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This may deplete power assist, requiring increased brake pedal force
2. Shift the vehicle to N (Neutral). This can be done while the vehicle is moving. After shifting to N (Neutral), firmly apply the brakes and steer the vehicle to a safe location.
3. Come to a complete stop, shift to P (Park), and turn the vehicle off by pressing POWER.
4. Set the parking brake."

If you wanted to test it, you could find a straight, empty stretch of road, shift into neutral while traveling at a safe speed and maintaining pressure on the accelerator (to simulate a stuck accelerator pedal).
 

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Regarding using the brakes, I've seen several topics about this here and I still don't see a clear conclusion. Some say it works and overrides the accelerator (or overpowers it), others say the brakes didn't work.
So simply try it. I did. The brake pedal appears to simply turn off the accelerator pedal. With brake pedal lightly touched I floored it and got zero response. Same with shifting to Neutral. No sound, no strain, no response to accelerator at all.
 

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As most know, Toyota (and I assume other companies) had sudden acceleration issues several years ago. At first it seemed to be due to the floor mats, but then it morphed into a potential problem with electronic acceleration control (vs. manual control via cable) on newer cars at the time. In one of the early incidents a highway patrolman and his family were killed while he was talking to 911 and saying his car was going 120 mph and the brakes would not work on a Lexus. I thought that issue was fixed on later cars by disabling the accelerator if you hit the brakes.
That incident, which started the whole Toyota floor mat unintended acceleration stuff, was due to floor mat interference. The car was a service loaner with the incorrect floor mats in it. A previous user of the same loaner car had also experienced the floor mat getting the accelerator stuck, but was able to stop the car and pull the floor mat out. That led to a recall that involved new floor mats, new accelerator pedals with more clearance, and/or cutting off the bottom of the accelerator pedals.

Subsequently, some accelerator pedal assemblies (from a specific supplier in some Toyota cars) were found to be sticky and were replaced under recall, supposedly after someone parked a Toyota in front of a Toyota dealer with the engine racing due to the accelerator stuck down with no floor mats or other objects pushing it down.

There were also unproven accusations of software bugs which stuck around in popular opinion because it was very difficult to prove a negative in this case.

At the time (2009), relatively few cars had drive-by-wire accelerators with software that set the accelerator input to zero if the brake was pressed. This become more common afterward (and some companies offers software updates to add that feature). @MisterJJ above described what this software feature does.

To this day, Toyota maintenance schedules include checking the installation of the driver's floor mat.
 

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So simply try it. I did. The brake pedal appears to simply turn off the accelerator pedal. With brake pedal lightly touched I floored it and got zero response. Same with shifting to Neutral. No sound, no strain, no response to accelerator at all.
That makes sense since the brake pedal engages regenerative braking, so it has to have some control over acceleration. It seems reasonable for the designers to assume that applying pressure to the brake pedal means no acceleration is desired.

If you want regenerative braking blended with acceleration, that's what the steering wheel paddle is for.
 

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So simply try it. I did. The brake pedal appears to simply turn off the accelerator pedal. With brake pedal lightly touched I floored it and got zero response. Same with shifting to Neutral. No sound, no strain, no response to accelerator at all.
OK, I went out and tried it. And thanks MichBolt for the quote from the Bolt owner's manual.

While accelerating I hit the brake and it did slow down my 2020 Bolt and worked as you described. It seemed to stop the motor too, but I'm not certain of that and will try again one of these days.

I also tried shifting to neutral. That worked too, but it is a tiny bit tricky in that you need to press up on the shifter twice (more than twice worked as well) from D or L. If you wait too long between the presses (about 1 sec or more) then it didn't work for me and you need to try again. A couple of times I did it twice quickly and it didn't seem to work, but I may have not pressed hard enough on the shifter (or maybe I pressed twice too fast). If in a panic to stop, this would not be my first choice but it works.

I didn't try the Start/Stop button because that is probably the last thing I'd think of so it would be my third choice, but that's just me.

In the links I provided there were a few people who seemed to feel that breaking did not stop the acceleration but I may have misinterpreted one, and in another the driver mentioned he may not have remembered things correctly due to the confusion (can't blame him).
 

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Inspecting the car I found that my floor mat (tux mats) had shifted forward a couple inches just enough to catch the accelerator pedal and preventing it from returning normally.
Glad you came out OK and I appreciate your detailed post providing all the information. I switched to Weather Tech mats because I had a similar problem in my 2012 Volt. Put Weather Tech floor mats in that Volt soon after, then in my 2015 and the day I got home with my 2022 Bolt, I ordered the Weather Tech floor mats for it too. Installed them yesterday and I'm very confident that they won't interfere with the brake
 
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