Prius C Moves forward when shifting in reverse...

^^^ And this is his/her 1 post as well!

 

A fact that hasn't gone unnoticed. Let's see if they ever log in again. The OP still hasn't.

 

i cal this....

 

OP posted this the night that consumer reports were released with prius leading the pack in customer satisfaction. interesting

 

Wow people on here are getting a little extreme. Did no one read my post?

i haven't tried to replicate it (I have no idea if shifting gears without having started properly is "bad" for the car) but what I observed seems to be a possible explanation for these experiences.

 

I have but I didn't feel it provided an explanation. Although vehicles with SKS require the brake pedal to be depressed when pushing the Start button, it doesn't make any difference at this stage because of the parking prawl that is engaged while the shift is in the P position. You can release the foot brake once in Ready mode and I often will if I'm not moving immeadiately.

To move the shift from P to R there is an interlock device that requires you to depress the brake pedal. If this interlock becomes stuck, there is a shift lock override which requires use of a screwdriver as set out on Page 471 of the US manual.

http://www.toyota.com/t3Portal/document/om/OM52B58U/pdf/sec_5-2.pdf

I can't tell you if the parking prawl disengages (my understanding is that it doesn't), but if the shift lever is not in the "P" position when you attempt to start the vehicle, it will not start, you'll get a warning beep and the MFD will display a message saying "Shift to P position to start".

If you have a safe place in which to do it, please give it a go, because at the moment I'm not seeing how these circumstances can easily arise. We're also not talking about an extreme slope where perhaps the vehicle might roll (and remember you do have the Hill Start Assist available should you feel this is necessary)

Remember here that the initial post stated "As soon as I pressed the gas pedal my car started moving forward and hit the curb right in front of the car. I couldn't believe my eyes so I put the gear back to Parking and back to reverse, and as soon as i touched gas, it again accelerated forward." That clearly is a different scenario.

The more recent post by another first timer describes an extremely vague situation that allows little scope for really understanding what (if anything) happened, then describes the same thing happening with their window. At this point the cynic in me feels that it's just getting silly... these systems aren't related to each other at all.

Not having a go at you at all here - I think when I first read your post I was on my mobile and not really wanting to write out a long post with links, then I probably forgot about it.

The other two posts by the one-time-only-posters though - I've moved from benefit of the doubt to the presumption that both are attempts at FUD until shown otherwise. Looks like a duck, quacks like a duck, etc. Does it not strike you as odd that neither poster has ever logged in again to get feedback from the owner community about their problem?

 

Hrm... so I went down to the garage and tried to replicate what I *thought* happened (pressed start with no foot on the brake, and put into reverse). The car didn't move, and further, the multi-information display was showing a clear message that I needed to shift back to P and press start.

This has me starting to wonder if the situation I experienced WAS what the OP described; when it happened to me it *did* feel like touching the gas was pushing me forwards despite my gear shift and displays reporting that I was in reverse. But I assumed that the more likely scenario was that I had done my startup procedure incorrectly, and was in fact somehow rolling forward in neutral. This seemed supported by the fact that when I shifted back to P, turned the car off and back on again, everything was fine. And the problem hasn't repeated itself since.

I am scheduled to go to my dealership tomorrow to get my snows put on (yay canadian winters) so I will inquire if there is anything they can check for.

I will say this: yes, posters who sign up, make a negative claim and then dissappear are suspect, but its also possible that they signed up because of the incident, and probably if all they got was people telling them they're lying and making things up, they probably didn't bother continuing.

Anyway, i'm not drawing any conclusions about the experience, because as i said, my initial inclination was that i had probably done something wrong or was misreading the situation, and maybe I was... but regardless of what ACTUALLY happened, i can honestly say the OP's description does match what SEEMED to happen.

 

If you click on a user's name a panel comes up showing when the site last saw them. In both cases the first time posters never even logged in again. Therefore they didn't see the response to their posts and never came back to look.

Yes it's possible that they logged out and revisited without logging in again, but at this point we're stretching to avoid calling out the obvious. If you read my earlier posts I was more open minded, but now at this end of the thread it looks and quacks too much like a duck, so I'm calling it a duck until shown otherwise.

Thanks for giving it a go. If you do ever have something happen I hope you do let us all know.

 

I went to a USPS yesterday, and they had small incline on their parking lot. So I thought, it will be a good test for this situation.I pushed start once (without depressing the brake pedal) and put my CVT in reverse, released the parking brake and OMG, my car started rolling forward, WHAT a surprise. No rocket science, just a common sense and gravity forces. CVT doesn't have gears, it's just the belts controlled by computer, so there is NOTHING to resist gravity forces.

 

No Priuses have CVTs with belts. The power split device does NOT utilize them and is NOT a belt/pulley design.

See Toyota Prius - Power Split Device and Graham's Toyota Prius (under Understanding Your Prius).

 

Check this link under transmission: Toyota Prius c - 2012 Performance & Specifications

 

What about it? See AUTOMOTIVE TECHNICAL ARTICLES, specifically the first two hybrid articles.

All Hybrid Synergy Drive Hybrid utilize a similar design, consisting of two motor/generators and a planetary gearset. There may be another planetary gearset for speed reduction (started on Gen 3 Prius). I took some pics at Picasa Web Albums - cwerdna - Prius Connect... showing Gen 2 and Gen 3 Prius components.

For a disassembly, see Towing revisited: Weber State | PriusChat. Bob Wilson bought some SAE papers describing Prius c differences (see SAE papers describing Prius c | PriusChat).

 

Electronically controlled Continuously Variable Transmission (ECVT) is Toyota's way of referring to the power split device. It's a planetary gear controlled by computer to become an effective CVT without being a traditional CVT. Wikipedia sums it up reasonably: Hybrid Synergy Drive - Wikipedia, the free encyclopedia

Either way this doesn't change the point you were making - a Prius can roll forward under gravity even with R selected.

 

There are 2 types of CVT.

The belt type is for traditional vehicles, to offer a wide range of power transfer from engine to wheels.

The split type is for full hybrids, to provide a means of transfer power to & from the motors & engine.

 

Thanks for the links! Will read them with pleasure.

 

There's at least one more type, but it doesn't exist in North America, the toroidal type. Supposedly, the transmission fluid won't work properly at temps encountered in parts of NA, so Nissan doesn't sell it here. It exists in some JDM Nissan vehicles. I have seen working models of these and the transmissions themselves at Tokyo Motor Show.

See HowStuffWorks "Toroidal CVTs" and http://www.nissan-global.com/PDF/tcvt_e.pdf.

 

So does this mean that my initial assessment of the situation is in fact a possible explanation? (My quick test yesterday might have been on too level of a surface) The only thing I don't recall was the multi-information display warning to return to P. But given that you have to be in a kind of absent minded state to start the car improperly, I guess it's possible (albeit worrying) that I missed that too.

The main points are that a car can roll under gravity, and if your engine isn't properly started (which can be less obvious on a hybrid where you don't necessarily expect the noise and vibration of the ICE), you can be pressing the accelerator when this happens, and thus "feel" like the accelerator is causing the movement.

 

Not really.

Yes, if in READY mode.

I haven't tested it, but in this scenario I believe the parking pawl will still be engaged. As I understand it - though I can't remember exactly where I've read it, it's not mechanically linked to the shift selector and is operated by a small electric motor, so I would not assume it would be disengaged simply by moving the shift selector without the car being in READY mode. I think in the situation you describe the c will actually still be in Park, effectively.

By the way, you also can't turn the c off without putting the selector into Park. If you don't have SKS, you won't be able to physically remove your key without the selector being in Park. With SKS, if the selector is not in Park and you push the Power button, this will put you in ACC mode.

 

Well, I won't try to make any more technical assumptions. I'm definitely green when it comes to the ins and outs of the vehicle. Ill gladly accept whatever explanation people agree upon (including user error) if it explains the occurrence!

 

Just tried to recreate the scenario at the original location where it occurred. Powered on without brake peddle, put in reverse. Car definitely rolled forwards. So yes, shifting out of park without the vehicle being in "ready" mode 100% definitely disengages park and puts car in neutral. Powering on properly, the car went backwards as expected when put in reverse, even on downwards incline, and even without any accelerator peddle.

Long story short, I'm certain it's exactly as I originally thought, and I'm betting this is what happened to the other posters as well. It genuinely does feel like what they describe, but in the end it comes down to user error.