No Power, nothing

It most likely is a dead 12v battery.

You can get the car started with a "jump," using contacts under the hood.

But you must be very careful. If you reverse the leads/polarity you can
fry one or more computers, and the repair bill comes in at ~$4K.

Once it's started 12v power is provided from the HV battery via the
DC to DC converter. (Hint; drive to a dealer and get a new battery.)

Better read up on this in your Owner's Manual just to be safe. :rockon:

 

Also activate Maintenance Mode & check the voltage regularly (monthly or quarterly). When the numbers get closer to marginal you may want to check more often or buy a battery on your schedule rather than the battery's.

You can easily check out your battery status/charging system using the MFD in maintenance mode. No tools required.

1. Get your Prius into "Accessory Mode" - Press the power button without touching the brake pedal.
2. Put the MFD into "Maintenance Mode" - Press and hold the "Info" button on the MFD while turning the headlights on and off 4 times.
3. Press the "Menu" field on the screen.
4. Press the "Display Check" field.
5. Press the "Signal Check" field.
6. The 12v battery voltage will be one of the items listed, it should be above 12 volts. If it is lower, either the battery needs replacement or the charging system is not functioning correctly - see step 7.
7. Put a small load on the battery by pressing the power button again without touching the brake pedal. The voltage should stay above 12v. If it drops significantly, you need a new battery.
8. Now get your Prius into "Ready Mode" - step on the brake and press the power button. The battery voltage should immediately rise to 13.8 volts (Your Prius uses constant voltage charging). If it is lower, the battery will never charge; if it is much above 14 volts, your 12v battery will get cooked.
9. Shutting the car down will reset the system back to normal operation.

If you need to get a new 12v battery, you can opt for a dealer replacement or get a better battery at a lower price at: http://www.elearnaid.com/12vo1topraub.html
and install it yourself.

JeffD

 

JimN,
The Maintenance Mode check sequence you provided above does not work for my 2005, Option 6. I need your help to find out what I did wrong.

Step 1 - I placed the Prius into the Accessory Mode.
Step 2 - While holding the Info button on the MFD side panel and turning the headlights on/off 4 times, the MFD screen went dark. After the fourth on/off sequence was complete, I released the Info button and the MFD displayed the Nav screen. I then pressed the Info button and the main menu screen appeared. I pressed the Maintenance button on the MFD screen and the maintenance schedule screen appeared. I pressed the Battery button and the battery replacement schedule appeared, which BTW was blank because no data had been entered.

Obviously, I was not able to progress to your Step 3.

I would appreciate your help so I can determine the health of the OEM 12V battery, which is over 5 years old.

Thanks,
Hank

 

In step 2 that should be, "turn the headlights on and off three times", not 4. See
http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html

 

Thanks Richard, but it still would not enter Maintenance Mode with the three on/off cycles. Then after the first time I tried this without success, each time I tried the on/off sequence again the display entered Accessory Mode/Nav screen.

Is a time delay needed after the Info button & headlight on/off sequence is tried before trying it again?