Sudden Acceleration precursor?

downhill?

I can't speak to everything else but were you going doing a hill at the time or prior? If the battery is pretty full (SoC on my ScanGauge at somewhere about past ~70% on my 2nd gen), as you're slowing, the car will essentially kick itself into something like B mode where the ICE RPMs go quite high (yes, even possibly past 3400 rpm) while going down a hill. This will happen w/no foot on the accelerator and even a foot on the brake.

This is presumably to prevent the HV battery from getting overcharged.

I can repro this quite frequently now as I have to go down a fairly long downhill grade to get home.

 

Re: downhill?

I've had something similar to this happen on my GenII when going downhill on a winding country road. The engine stayed around 2400rpm despite my not giving any throttle input BUT the car did not push or act as if it was accelerating either so I just continued driving. I've only experienced this once in 126,000 miles of driving the car but it may just be the first time I've noticed it. *shrug*

 

You should take the car to the dealer immediately. Most likely the EDR won't show any faults but it's important to make sure they note your description of the problem on the service ticket, otherwise it won't be in their system.

 

LOL !!

I'm not sure a Prius could 'really take off' under any circumstances.

I always laugh when I read that story about that idiot that said his brakes couldn't overcome the incredibly powerful engine of his Prius.

REV

 

x2

 

"Anybody have any idea what exactly happened?"
How do you expect someone who was a thousand miles away to know what happened?
Go talk with the service dept.

 

that's it, i'm dumping mine today!

 

Was the battery full of charge? If so, that was the HSD dumping energy by spinning the ICE with no fuel injected. It happens from time to time.

Just to reiterate - NO Prius has EVER "suddenly taken off" without the accelerator pedal involved! Either caused by mechanical or electronic faults. This has been proven by two separate investigations by people who are supposed to be somewhat intelligent. Further, because the engine IS NOT directly connected to the wheels, the Prius WILL NOT take off if you don't want it to and don't make a mistake with the controls. The engine -may- rev up, but that will have minimal effect on the drive to the ground.

So a floor mat may kill you if you're asleep at the wheel but not the Prius "ghost in the machine".

 

The OP stated:

Clearly this is not a case of burning off excess charge.

I worry about the recent tampering with the electrical system. Most likely this is some sort of weird one-time event, noticed by the OP because of the recent work, but it could be a real problem. I suggest close monitoring over the next few weeks. If you see it again, visit the dealer.

Tom

 

You are seriously overstating the findings. They made it crystal clear that they were not proving anything, particularly a negative. Rather, with considerable searching and testing, they were finding no evidence to support claims of uncontrollable UA.

They did find a tin whisker electronic fault in a Camry part, but it threw CEL codes, was easily controllable, and had other layers of protection remaining.

 

What I still can't understand is why people tinker around with the car and then whine on the forums that the car is acting funny. Tinker, whine complain, guarantee, sue....? It's a lifestyle and not a good one....

#1 Stop messing around with your car
#2 If it acts funny before or after tinkering go see your Toyota dealer. They'll know best what to do...But that costs money....
#3 Stop messing around with your car...
#4 Drive with your right foot and your right foot only.

Damn....

 

*And NASA didn't bother testing a Prius, just 6 old Camry's.

I'm sure the OP will rest easier now. Don't bother taking it to the dealer. NASA personally tested your car and it's perfect.

 

While NASA's deep dive into the electronic throttle control system covered just 6 Camrys, all from complaintants, NHTSA's other reviews cast a much wider net.

Based on complaints, they selected 58 vehicles to inspect in the field -- 19 Camrys, 8 each Corollas and ES350s, 7 RAV4s, and onesy-twoseys of other models. Two were Prii, but both accidents were low speed events too slow to trigger the event recorder and fire the airbags. One hit a curb, the other hit a parked car while trying to enter its own parking space.

NHTSA also purchased 23 Toyotas for inspections and performance and functional tests. 11 were non-UA Camrys of different years and configurations, used as design references. 9 were UA Camrys purchased from complaintants. They also purchased one Corolla, ES350, and RAV4 from UA complaintants.

After those tests, NHTSA then sent 6 of those UA Camrys to NASA. So while NASA itself tested on only 6 Camrys, 'The Gummint' inspected and tested much more.

 

Careful fuzzy, if you keep reading the studies you might learn something that you don't want to learn.

You might get a chuckle out the "comprehensive" study the NHTSA did regarding Audi's Unintended Acceleration problems. Yes, the same report that fueled the "driver error" excuse for the past few decades.

NHTSA Study: "An Examination of Sudden Acceleration" Jan. 1989 | The Center for Autosafety