prius loses all power when shutting off

This just sounds like 12V battery problem. Even if it’s only a year old it can have problems.

If the 12V battery is good then it’s very likely the connections. Terminals on battery are clean and tightened (don’t overtighten)? Negative battery cable has good connection to body? Negative cable to ring terminal is tight and not corroded? Connectors on positive terminal are inserted fully?

 

+1
When weird things happen, check the 12V battery and its ground first.

 

+2

 

no its not a fuse, when a fuse blows there is no power, it doesn't heal itself.. has to be replaced..
could be the switch inside the door going bad or sticking.. but I have not seen it on a prius, my old GM van the radio would not shut off because of the door switch,it was built into the locking mechanism. had to push it up with a screw driver.

 

that's a new one afair, where is the ground?

 

Wait so when I get to my destination and push the start button, everything goes off including the radio, that isn't normal?

 

can you lock the doors?

 

No, the cabin lights should still operate.

Glad it's fixed. I love it when it's easy. Just wish it was easy more often.
@valde3 & @Sam Spade ... High five!

 

Oh yes the lights still come on, the radio turns off, windows don't work. So that's normal?

 

and the car won't go!

 

Quite normal. (Except on the Gen 3 at least, the windows will still work after you shut off the car until you open a door. Not sure about Gen 2.

What the OP had was not normal.

So I'm totally confused by your initial comment in #8.

 

In post 8 I meant the radio shuts off, windows stop working, dash goes out, but the overhead lights come on. I am used to the radio staying on and windows still work till you open a door.

 

Hi Gilga, how did u fix it, I have the same issue. Thanks

 

It is so annoying that I have to slam my Prius door like 5 times to get any light, to start the power or to lock my Prius, or I have to slam the truck, which is even better. Help please

And the Prius re start now and then and has a message don’t turn off power, no Bluetooth, radios messed up and the clock messed up too!

 

I know this is an old thread but I've been having this exact same problem, except mine fixes itself and car comes back from totally dead if I open and close the right rear passenger door. I inspected and redid all the 12v battery connections last Spring and that solved it, but today the problem came back. So now I'm going to to see if anything is wrong with where the 12v battery connects again. For a while I was convinced that it was the power button itself because it primarily happens on a really fast light push of the button and never happens on a very firm slow intentional push.

My theory is one of the relays malfunctions when you turn the car off and there is a less than solid connection on the battery. But still not sure yet... If anyone has any thoughts about the details of how a Prius bricks itself when you turn it off and then sometimes randomly turns itself back on to the mode created when you push the power button twice without foot on the brake?

Sure would like to learn about this phenomenon!

 

Good starting place. I feel like a broken record because I said something like this yesterday on another thread. That ground connection to the body is not exactly what I would call robust. If it would just fall of completely, that would make it easy, but it just comes loose and then weird stuff happens.

 

I say the key is vibration. The contact between the 12v battery and the car is poor. Slamming the door creates enough vibration to temporarily restore the electrical path between the battery and the car. Enough to go into ready mode. And once it's ready, the DC/DC converter will happily keep the car going until you shut down.

I've seen similar on much lower-tech cars.

Somewhere in the wire path, something is shaking loose. It may be the clamps on the top of the battery, it may be the far-ends of the battery cables, and it may even be corrosion within the battery cables. I don't generally see that last one in cars with cabin batteries, but with underhood batteries sometimes you'll see the copper strands of the battery cable dissolve into green mush under the insulation. With all of these causes, the electrical path can continue to work part-time as long as something is shaking the car occasionally.

 

Worked on a friend's car where one of the battery post/clamp interfaces wasn't as shiny clean as it could have been. Worked just like a self-reset circuit breaker: walk up to the car, open the door, dome light comes on, other lights and stuff work, turn the key to start, starting current heats up that battery clamp and expands it, everything goes dark. Wait like ten minutes, clamp cools down and contracts, lights come back on.