Prius Rolled Backwards (and crashed)

You should AlWAYS use the parking brake. It should be used every time you park...P or not.

 

Hi All,

One possibility - as others have said the stab at the P button was too short, the car ended up in neutral. Due to not regularily reversing and braking hard, the auto-adjusters had not take up the slack on the drum brake shoes. So, applying the parking brake lever not all the way gives incomplete brake issue. These drum brake things are not hybrid or Prius specific. Lots of cars have drum rear brakes.

So, how did the car get into Park? Impact. The Park button is relative horizontal, and when the car hit something behind the button operator or switch contacts recoiled and set Park.

Good thing to do with cars with rear brakes is once every 10 K miles to get going in reverse at a good clip and apply the brakes firmly. This adjusts the brakes.

If this has not been done for 50 K miles or so, one may want to have the drums taken off and the auto-adjusters checked out. They only operate one-click at a time, so its easier to have a mechanic reset them properly, then to reverse and brake briskly 10 or 20 times. Also, if there is corrosion, they may not adjust automatically.

 

I just wanted to reiterate what someone else said previously, because it’s very relevant. The Prius park brake is fairly good in the forward direction but considerably less effective in the reverse direction.

Just yesterday I had to park nose first in an upward sloping driveway similar to the OP. Not really all that steep but I can tell you that I had to apply the park brake very firmly before it would hold with the park brake alone. I'd estimate that if it were in the other direction (down sloping) then I'd probably only need to apply it about half as hard.

One other thing, since I come from previously driving only manuals I have to admit to being just a little leery about using "park" as a brake. I know that it's a transmission lock and therefore a lot more effective than just the "engine brake" on a manual, but I still tend to treat it like just some extra insurance rather than a brake. When I have to stop on a slope I put it in neutral first, then firmly apply the park-brake, then take may foot off the driving brake and check that it holds and only then hit park (or just turn it off). I know this sounds like an overkill but that's just what I'm in the habit of doing. BTW. Does anyone else here do it that way?

 

This is exactly how you SHOULD do it. The parking brake is just that, a PARKING brake and it should be used 100% every time you park the car. Not to mention this takes the strain off the drivetrain which can only be a benefit.

 

Most cars, like the Prius, use cable operated rear brakes for parking. One of the tricks for easily setting this type of parking brake is to press hard on the service brake pedal as you press the parking brake. This lets the hydraulics do the hard work, while the parking brake cable only has to take up the slack. It's a lot easier than trying to do all the work with the parking brake.

Tom

 

Good tip, Tom. I always make sure my foot is firmly on the brake pedal until after Park is engaged and the parking brake is engaged. Even then, I find the car will roll back a bit against until the "Park" pawl is hitting if I'm on an uphill unless I really push the parking brake hard.

In those cases, I usually try to get one of the wheels up against the curb, first before engaging either.

 

Thanks for pointing out the mechanism - I have been doing this without thinking the reason why - other than the convenience of keeping the car motionless in between the transition from driving brake to parking brake. I suppose an added benefit is less wear and tear of the cable maybe?

 

:mod:

First of all your story does not make sense. You say you were inside for 30 seconds to 1 minute, during which time your Prius rolled backwards through 4 lanes of traffic. Within this time you say the Police "found" your vehicle.

It is highly unlikely that a random Police patrol would be so lucky as to "find" your vehicle so quickly even if it is causing trouble and cars are honking. 30 seconds to 1 minute is quite a response time -if someone called the police.

I will say: Operator Error.

But more than likely, since there are 2 negative posts on PriusChat in a row, I will say that this post is an attack.. yet again.

You are being paid by someone who is being paid by someone from the American Automobile Industry, or an Oil Company or a corporation, whose intent purpose is to generate negative press about the Prius (or all hybrid, energy conserving vehicles)

The less gas we use, the less money the oil companies make. That makes them VERY angry and ready to kill. So go try and kill somewhere else.

Pruis is a stable vehicle and is a very good car. No problems here.

 

Interesting, there have been a few postings recently the drivers got into an accident and playing the blame game pointing fingers to Toyota for brake problems.
Wake up and take responsibility for your actions.

 

I agree with your observations about the timing...but I think its a little far fetched that he's some sort of paid spy...come on...

 

i'm a newbie,
have a question though...
with the smart key, if you leave the car in the ON position, but exit the car with the smart key, will it shut off after you get a few feet away??
or did this guy leave his key in the car while he was inside?
i was asking because i wonder if by chance the car goes into this mystery runaway mode, could you throw the key out the window to disable the car and coast to a stop??
i am not bashing, i am suspect of the whole runaway thing myself. and i am sure if something started to runaway i could figure out how to shut it down or get into neutral or unstick the floormat.
but i want to tell my wife who is not so savvy what to do just in case... can she throw the keys out the window?? or will the car just keep happily running like this guys car seemed to do when it rolled backwards in "P"

 

It'll run until it's out of gas, or someone powers it down.

 

The Smart fob contains a CR2032 battery. That battery will eventually need replacement.

Suppose you are happily driving along at 70 mph on the freeway in heavy traffic, and the fob battery decides to die. You do not want your car to shut down just because of a dead fob, right? The Toyota engineers also decided this would be a very bad idea.

So, what will happen instead is that an amber icon will appear on the dashboard that provides you warning that the Smart system no longer can detect the fob. However the car will continue to run until you make it IG-OFF.

Then, to restart the car, you would have to either replace the fob battery first, or else insert the fob into the dashboard slot.

Bottom line: do not throw the fob out the window. It will cost you $400 to replace and it won't help you to stop the car, if that is what you need to do. Focus on shifting into N, holding the POWER button down for 3+ seconds, and/or removing the floor mat from the accelerator pedal - whatever will work for you.

 

i vote for parking brake not fully engaged.

as others have stated, parking brake set for reverse on an incline does not work as well, but still works.

about 2-3 years ago, i was parking downtown Oly, all of which slopes towards the Sound. was on a hill, set parking brake, went inside.

came back out later, noticed car had moved (i had wheels turned towards curb, yada yada and although car only moved less than a foot since was a bit away from curb the angle was waaay different)

was a bit alarmed since i thought i had done what i needed to do to prevent it, so immediately inspected car and found that i was 2 clicks away from a fully engaged parking brake. was not enough to roll away, but loose enough for the car to move. had the curb not been there, i am sure i would have gained enough momentum to do something i prefer to not think about

 

That's interesting Dave. Do you know if the car was in "park" at the time?

 

car was off

 

thx for the clarification of FOB functionality.
i will not tell the wifey to throw it out the window!!
i dont doubt that the insurance adjuster would pile all the blame onto toyota at this point.
but dont you want to truly understand what happened, so you can avoid it in the future??
you should be able to duplicate it if its a bad pawl in the "P" mode of the gearshift. or if the foot lever parking brake is weak.
i dont get how it moved , if it showed "P" when it was found after it rolled across the street. was it really in "P" or is the "P" broken.
it could be an electrical malfunction, that indicated P when its not really engaged, but just because the insurance guy says electric doesnt mean he bothered to actually figure anything out, its just convenient. are you going to get anything electric fixed on the car, or just cosmetic repairs, or file a lawsuit?
in the past my insurance adjuster has offered to cover damage due to road debris that wasnt there. does that mean that the phantom debris really cracked my lower airdam?? no it means they are just saying something to push the claim thru...
toyota electrical problem is about as easy a claim to make right now as stealing candy froma baby!!

 

So how do the wheels move if the transmission is locked? Does this mean that the "park lock" can jump out of lock under pressure?