Car Moved On Its Own. Any Ideas?

Is your car a Gen 4 (2016→2020) - or a 2007?

 

Was the parking brake set? If not, regardless of any faults that might exist in the electronic shift lever system, a rollaway is the driver’s responsibility.

As @Mendel Leisk (post #13), @ETC(SS) (post #17), and Toyota—“When you leave your vehicle, put the hybrid transaxle in ’P’ and set the parking brake,” 2007 Prius Owner’s Manual (PDF), page 15—have all kindly recommended, whenever there isn’t a driver at the controls and ready to operate the vehicle, the parking brake should be applied. It’s a separate, completely mechanical system, by the way.

This thread is about fourth-generation Prius cars (model years 2016 and later). Earlier models don’t record vehicle control history events in the way I described in post #4, but the shift-by-wire system was still designed to avoid inadvertent operation. I can’t say it’s impossible, of course, but a broken wire or loose connector wouldn’t be enough to cause an uncommanded shift from P⃣ to D⃣.

 

Just tested this in my Gen4 (so kind of moot I guess). Even in D, the car doesn't move at all with the handbrake/right-hand-foot brake/emergency brake/whatever your region calls it/etc applied. It feels like it's trying to move, so I guess if the road was slippery, and for some reason the front wheels had considerably more traction than the rear, it could drag the car along the road like a sledge.

It may sound harsh, but despite seeing a few posts like this, I feel it always comes back to user error. The car was almost certainly in D and not P, they don't magically shift by themselves (there are fail-safes and it is specifically designed to prevent this), and the manual brake probably wasn't applied.

Sure - stuff happens, people forget, people make mistakes, I know I do, but I feel with all electric cars people more often forget that just because they can't hear an engine running, doesn't mean it's not in a configuration where it can start moving once you take your foot off the brake. If you get out of a car for any reason, ALWAYS double check that it's in P, and the manual brake is applied, and if you live in an area where it's stupidly referred to as an "emergency brake", don't assume it's only for emergencies, it's for parking, use it as such, because failing to do the above can result in people getting killed.

 

If it's in "D" - open the door and the following happens:

• BEEPER sounds solidly;
• Yellow Exclamation Signal flashes;
• Red Seatbelt sign illuminates;
• Another RED Door Open sign illuminates;
• And the entire Middle screen lights up - "SHIFT TO "P" before exiting vehicle" is displayed.

It's basically impossible to get out while in "D".

But yes, while I don't always use the Park Brake when parked, I always use it if the car is still "ON".

 

While I agree all of that happens, I'm not so sure it's impossible. In fact, I'm going to argue people ignore all that kind of stuff quite a lot....

Humans get so used to such warnings they often ignore them, especially if they see/hear them a lot, which any Prius owner will experience. If I get out of my car to clear frost off the windows, while it's in P and Ready mode (so it can heat up) I'm going to be expecting the car to be flash warnings and beep at me. I also know I can ignore those warnings. So I get out of the car, I ignore the warning, but I don't realise that the very similar sounding warning and flashing lights/messages are actually telling me it's in D.

 

Yep - I'm not experienced with that - frost, ice, snow - not something which happens here. There are places not far away where they would get frost in winter.

 

This all could be wrong as the car is 3 Generations older so might behave differently - I've asked the Moderators to move this to a new Thread for Gen 2.

 

When I first got my Prius (and even occasionally now) I would hear silence and assume the engine was off and in P. My brain has been programmed to think that the silence meant I could safely exit the car. True, there would be warning sounds, but I would ignore them. It was when I could feel the car creeping forward that I would go in a panic and quickly press the brake. Several times, I was outside of my car before I noticed.

 

Yep - been there myself, more than once.

Really it's a design issue. Important safety warnings, like, you know, the driver exiting the vehicle while the car is in D, should be very different and much more persuasive than warnings that can safely be ignored in the short term.

 

Maybe. But I think the problem is actually the constant warning and reminder noise given out by many different things in situations that that they can and will be ignored. That just gets people used to ignoring warning noise.

So making the noise louder isn't really a good fix. And there are situations where driving with your door open is a useful option so the noise shouldn't be that loud.

 

julie, julie, julie

the dealer is going to make you pay...

 

What’s the history of the car bought new or used? It’s refreshing you understand the lurching the car does.

It may have a damaged park pawl which is a lever that engages the trans and locks it into place when in park. I have seen a few here with issues.

If used check it’s history. Go to Toyota.com/owners forum and join have your insurance card handy as it requires the cars vin.

Once joined you will see every event the car has seen an authorized Toyota dealer for service. See what has been going on with the car.

If you do go to the dealer have them check that pawl. Try parking on an incline see if it engages properly.

 

Um, I am totally intrigued by which situations you find it useful to drive with the door open? Please elucidate?

E.g., I have HEARD of folks in a very dense fog driving very slowly with the door open and a flashlight shining directly down to track the white line on the side of the road so that they didn’t simply run off the road, but I have not found anyone who would admit to actually doing that.

( I had a 1959 SAAB 93B with “suicide doors” that were hinged at the rear and opened to the front (some 1930s cars had those also). Since the airstream force would tend to fling the door wide open and rip it off the hinges, on that car we were particularly careful to make sure the doors were fully closed and locked before starting off.)

But I’m open to suggestions!

 

Mostly just ment driving up to a lift or pit in a shop. Maybe also some other exact parking. But the main point of my post was the unnecessary warning and reminder noise that people just get used to ignoring.

 

i sometimes crack it open to see the parking line as i back in to a spot

 

Have someone (who's NOT PREGNANT!) repeat the same dance but purposely put the car in N after startup and see what happens. I'm thinking that a door closing or you leaning/bumping the car while cleaning the windshield dislodged it from its icy lock.

IIRC in a long ago thread, a woman with a big winter jacket had issues with the vehicle operating controls caused by the large sleeves catching on things.

 

The car is haunted quick call ghostbusters.