Start button does nothing

Even though you have a new 12v battery does not mean its charged. It can discharge overnight with just the hatch light left on. From the sounds of it you are partially charging it with the jump.

 

Do you have a secure place - like a garage - to leave your car unlocked overnight? Do you have a 12v battery charger?

 

the hv battery is not related to make the car ready, but getting a change by a jumper tells you everything you need to know. the 12 volt is not supplying proper voltage.
get yourself a digital volt meter and take a reading with the car off at the jump point under the hood.

 

This is what I would do:

Disconnect the 12V battery.
Charge the 12V battery overnight - you'll need to leave the car (trunk) open to get access to the battery.
Reconnect the 12v battery
Push the start button once. Wait 15 seconds.
Push and hold the start button again
Note the level of charge (bars) of the HV bat if it comes up on the MFD

(This has worked for me on Gen 2 and 3 Priuses, many many times. Yours might be different)

Good luck

 

If you are using a cheap meter some read high. Harbor Freight meters are bad about reading dc volts high. If not, you probably have a loose terminal in the fuse box or an intermittent fuse or fusible link. Jiggling it could be making contact occasionally. Check voltages throughout the fuse boxes when it does not work, not just at the jump point. Pray the issue is not your 125 amp dc to dc fuse; its hard to see much less replace. Ten to one you have not replaced it.

 

Those all depend on the system going to Ready. Perhaps your observation that "jumping makes it work" is a red herring. Have you checked the keyfob battery? The stoplight switch?

 

Not really. This car is networked to the max. I would certainly try the jump again and or a good 12v charge. You need the codes read pronto. The techstream hack version can be difficult to setup. I would get someone to read the codes. That may solve the problem quickly.

 

Sounds like a network communication issue which could be one of several ecus or poor power/ground. How did you get it to start?

 

I think you have a bad battery or bad connections at the battery. Check the ground cable at both ends.

The fact you can jump start it and drive says just about everything else is ok.

 

May 4

May 17

It seems the pattern is the same, even two weeks later. Jump it and wait for a couple of hours and it will start. The second time it would drive for an hour but not restart.

1. Both times you jumped directly to the battery terminals?

2. Or was the negative jump source connected to chassis?

3. Were you wiggling or pulling on wires and cables as you waited for the jump?

Sometimes a bad connection will allow an extremely low current through such that when there is no load downstream of the bad connection, a high impedance (eg no added load) meter* can read proper voltages. But with a load, the bad connection can reduce the downstream voltage. A poor connection on the negative side is just as bad as a poor connection on the positive side.

4. If measuring at the front jump point when it fails, what is the voltage with the headlights on?

5. With the headlights on, what is the voltage between the negative battery terminal and a good bare metal chassis ground?

* Almost all modern meters are high impedance. High impedance meters can read induced, current limited "ghost or floating" voltages which can not power some loads. Old school analog meters added a minor load and mechanic test lights add a small to significant load depending on the test light / power probe. Test lights and power probes can cause problems if used indiscriminately. Some multimeters have a special "Low Z" (low impedance) mode which helps reduce false "ghost or floating" readings.