problems with starting car

Recently it is frequently happening that when I turn on my 2008 Prius the car doesn't start, the digital information panel seems dim and all the of "problem icons" light up. I sometimes have to turn the car on and off a few times before everything works properly and the car will start. On one trip the whole center digital panel that shows graphical information was simply blank; it didn't show up again until the next day. Another strange thing: when this happens, the speedometer apparently switches from miles to KM, and I have to manually switch it back to miles.

This only seems to happen the first time I start my car for the day - on subsequent trips in the same day I have not yet had any issue.

Any ideas about what is causing this and what is going on here? Is this an issue with the electronics or computer system? Anyone else ever had this happen before and is there anything I might be able to try myself to fix it?

 

thanks for your reply. Will I eventually not be able to start the car at all if the 12v battery dies?

I'm going abroad very soon and may be away for awhile so instead of replacing the battery right before leaving, when my car will be sitting unused, I'd rather do it when I return - but if I can't start my car on returning home, that will of course be a problem!

 

New development here, I'd like to get your feedback on, to make sure you still think this is the 12v.

Just tried to start my car - wouldn't start up, information panel blank, but did get an actual warning light this time, and found the explanation for it on p. 489 of my manual:

Malfunction indicator lamp
malfunction in:
- the emission control system
- the electronic engine control system
- the electronic hybrid system control system; or
- the electronic throttle control system

that seems like a pretty wide range possibilities! but none of them indicate battery? at any rate, I can't start the car at all now.

I should also note I heard a strange consistent "groaning" sound coming from under the hood this time while trying to get the car to start, and the sound persisted even when I turned the car off?

 

Ok I actually have an electric 12 volt charger, which has many different settings for charging. But I don't have much experience using it! I hooked it up and was able to get the car started - but when I removed the cables, the car died again. So I'm now leaving it hooked up on a lower setting for awhile, hoping it will charge up and the battery will hold the charge.

I'm wondering if there is a way for me to somehow get the 12 volt charged to maximum so it will last me for the next 2 weeks before I leave? Because in 2 weeks I'm simply going to be storing the car anyway. I saw one thread where someone said if you put the car in "ready" mode and just leave it alone for 2 hours, that will charge the 12 volt battery to maximum... Is this accurate?

 

Ok just an update here. I left the battery charger hooked up since about 3pm yesterday charging at 2amps. Nothing at all. Disconnected just now and tried to start car. Car still won't start, showing same warning light, and is still making strange groaning sound. The charger never lit up to show the battery was fully charged. Should I keep trying to charge at this point or does this mean the battery is totally dead?

Also, I should note, - don't know if this matters - I could not get the car into ready mode, or actually get the car to start, even after hooking up the charger - I got a "P lock warning" telling me to move the car to level ground. After some searching I found a thread this happens if the fusebox is open, so maybe that is normal when trying to charge the 12v?

Starting to wonder if I'm going to need to have the car towed to the dealer!