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Discussion Starter #1
Today my 2014 Volt with 114K miles showed it's first ever problem. When I selected "Drive" and pressed the accelerator to move out, it jumped ahead like I had pressed the pedal to the floor! I had to jam on the brake to get it under control. After that it seemed to run like an IC engined car with the choke stuck on fast idle. At every traffic light or stop sign it wanted to creep ahead strongly requiring a firm press on the brake to keep it stopped. It took a very light touch on the throttle to drive in city traffic. The car ran at 35 mph in "Drive" without pressing the pedal. It is like the "Sport" driving mode on steroids! The power (KW) indicator in the driver's display showed no power regeneration when the brake was applied. It felt like the friction brakes only were working. Any thoughts on what might have happened? Does it need a service appointment to reprogram the throttle response? There were no warning codes and otherwise the car ran normally.
 

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Dumb first question, but do you have floor mats? A large portion of the unintended acceleration issues Toyota had a few years back came from folks who had added floor mats and the pedal getting stuck under them.

No regen when the brake is applied and the described acceleration both fit with the car believing the accelerator is depressed - if the accelerator is down a little and the brake is pressed, it goes straight to friction braking immediately with no regen.

The accelerator pedal sensor is a multipart unit with failure mode detection on both sides, so it's not supposed to be able to fail in a fashion that lets the car think it's depressed and working, and I haven't read of problems with it before, but there's always a first time...
 

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There's little question that you need a service appointment. There is probably some control module that is malfunctioning.
 

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Dumb first question, but do you have floor mats? A large portion of the unintended acceleration issues Toyota had a few years back came from folks who had added floor mats and the pedal getting stuck under them.
At that time Toyota used a risky design for the throttle - it comes up from the floor. GM used and still uses a hanging throttle. The difference is that a floor rise throttle can be depressed by the floor mat pushing forward. This cannot happen with a hanging throttle.

In addition to a risky throttle design, Toyota's floor mat retainers from that era were crap. My wife's 2007 Solara had nothing but problems with the OEM driver side floor mat coming lose from the retainers and sliding towards the throttle and brake pedal. Now that I put an aftermarket floor mat in that's nearly twice as thick as the OEM mats, making it a lot stiffer and thus less likely to disconnect from the retaining clips we haven't had a single instance of the floor mat slipping towards the throttle.

I also read the NASA report. NASA's conclusion was that the vehicle they tested didn't have an issue with the throttle control, but the design of the throttle control system could result in a failure mode indicating a wide open throttle request from the driver.

Bottom line between the NASA report and my personal experience with a Solara of that era is that in my opinion Toyota was 100% at fault in every single case of unintended acceleration that couldn't be traced to the driver hitting the wrong pedal.
 

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At that time Toyota used a risky design for the throttle - it comes up from the floor. GM used and still uses a hanging throttle. The difference is that a floor rise throttle can be depressed by the floor mat pushing forward. This cannot happen with a hanging throttle.

In addition to a risky throttle design, Toyota's floor mat retainers from that era were crap. My wife's 2007 Solara had nothing but problems with the OEM driver side floor mat coming lose from the retainers and sliding towards the throttle and brake pedal. Now that I put an aftermarket floor mat in that's nearly twice as thick as the OEM mats, making it a lot stiffer and thus less likely to disconnect from the retaining clips we haven't had a single instance of the floor mat slipping towards the throttle.

I also read the NASA report. NASA's conclusion was that the vehicle they tested didn't have an issue with the throttle control, but the design of the throttle control system could result in a failure mode indicating a wide open throttle request from the driver.

Bottom line between the NASA report and my personal experience with a Solara of that era is that in my opinion Toyota was 100% at fault in every single case of unintended acceleration that couldn't be traced to the driver hitting the wrong pedal.
Yet many other cars use floor mounted throttles and are fine.... It’s operator error. I mean, weren’t most of the “problems” with Prius’s? Their owners aren’t known for intelligence...
 

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My 2008 RAV4 has the accelerator pedal hanging from the firewall. Here is a before/after photo where Toyota trimmed the bottom of the pedal to help prevent floor mat entrapment:

 

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That's high tech. :p
 

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We have a RAV4. It has an accelerator pedal that comes from the top. The wife bought some generic floor mats for the driver and passenger side. I told her I thought this was OK for the passenger side, but not the driver's side as it wasn't tacked down right, and didn't meet form fit and function and this sort of thing had been a safety issue in cars and could pose a safety hazard. She totally blew me off. She mostly drives the RAV. Eventually we took a long trip in it, and I got a chance to drive it with these floor mats. There were several circumstances where that mat interfered with the accelerator. You wouldn't think it possible with the pedal design, but it did. When we got back from the trip I put the factory mat back into the driver side, and left it as end of discussion.
 

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Discussion Starter #9
saghost wrote - "Dumb first question, but do you have floor mats? A large portion of the unintended acceleration issues Toyota had a few years back came from folks who had added floor mats and the pedal getting stuck under them." At the time I said to myself, "This is not where I want this thread to go. I have a technical Volt problem not a stupid floor mat problem." I fussed with the situation for four days, checking with a former Voltec trained technician, going so far as to schedule a service appointment. It was becoming difficult to drive the car safely. Finally I needed to accelerate quickly to merge into traffic and the throttle stayed at a uncomfortably high level after the incident. I pulled over for safety and put the car in park. I decided to reach down and fiddle with the gas pedal to see if I could pull it back to a more reasonable level for the trip home to park it in the garage. Lo and behold! I couldn't find the gas pedal! It was under the edge of the molded PVC plastic floor mat! Re-position floor mat and problem solved! Apparently I had taken the driver's mat out several days earlier to clean the salt off it and not put it back correctly. I am not a total technical moron but I missed this. (Much egg on face!!) I guess it just goes to show you that you should look for the simple answer first. Sorry for the wasted time and thanks for the input.
 

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Ultimately, it wasn't the factory floor mats that caused the Toyota acceleration problem. Apparently a lot of people were adding 2 or even 3 more mats ON TOP of the factory mats for some reason. This stack 'o mats would often get caught on the pedal.
 
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