2010 Prius iv weird start up! Help!!

So I have a 2010 prius iv, I know this is technically the iii forum, but there's not much going on in the designated iv forum, so I thought I'd give this a try...

I've had my prius for about 2 years, purchased it used, and it has just under 60,000 miles presently. I haven't had any maintenance done aside from regular oil changes and tires and such. Just today it's begun doing something weird, I haven't seen the same issue in another post, and I really know nothing about cars, especially hybrid cars, so any input/suggestions would be appreciated...

So today I get in the car and put my foot on the brake to start it and notice the brake is really heavy. I press the start button and no light comes on. I take my foot off the brake, push the button a couple times, but no light. So then I wait a minute or so, push the brake and it makes a weird like groan-type noise. I push the start button and it turns orange, but not green, and the check engine light comes on. I press the button again to turn it off, wait a minute or so, and then put my foot on the brake. It's no longer heavy, and the car starts normally with no engine light or any other kind of light.

I ran a few errands and the car powered on/off normally. But then tonight, we took the car out, had it parked about two hours, and when we came back out, the exact same thing happened! Same sequence and everything. So now I'm a little concerned. I will take it to the dealer in the next day or so, but I was hoping to get some kind of idea of what to expect.

A little but of background (I don't know that it makes a difference): Since May of this year, it has not been uncommon for me to go a day or two without driving it at all. I don't think its sat for more than 3 days at the longest, but I can't really remember. Although just yesterday I had to drive it almost 200 miles round trip, and it did fine.

 

thanks!! I'm hoping it's just the 12V, it seems relatively inexpensive as far as car repairs go...

also, you might be right on the model, I tried looking online to clarify for myself, and now I'm just more confused I'll have to go through my paperwork in the morning

 

Thanks everyone for your input. Unfortunately, we are still having some issues. The day after my original post, I switched cars with my fiance because I had an appointment about 2 hours away. That morning, he went outside to start the car and, of course, it did not start. I guess he got this message: MALFUNCTION WHEN PARKING, PARK IN A FLAT PLACE AND APPLY PARKING BRAKE SECURELY. He shut the car off, came back in the house, but when he went to try it again 10 minutes later, the car started normally without any messages or lights. Then again, at the end of the day, the car would not start (not sure if he got the error message this time), but about 5 minutes later, it turned on normally.

Once he got it running, he took it straight to the dealer and they said they'd get to it in the morning. We were like "oh, that's great because it only gives us problems during cold starts", but of course the next day the dealer calls and says they can't find any problems, the battery is fine, and it started up normally for them. It was a little hard for me to believe since it had been an issue consistently for the last 2 days. I was pretty sure that when we went in the evening it would not start up normally, but lo and behold, it was fine.

Fast forward to this morning (the car was not driven on Saturday), and SURPRISE, the car does not start. First attempt: heavy break, orange light, weird groaning noise, check engine light, and yellow "triangle of doom". I power off, the check engine light disappears, the triangle is still there. Second attempt: car starts seemingly normal, triangle is still there (no other message), but weirdly, that display in the dashboard that shows settings/mpg/etc is blank. I drive around the block, car is driving ok, display is still gone. I try pushing the button for display options, but nothing shows up on the screen. So I park and shut off. Third attempt: car starts normally, display is on, no more triangle.

So that is where I'm at. Thank you to anyone who actually took the time to read all that. I'm not sure what to do at this point. I've had a past issue with the service dept at our local dealership, and I'm just not particularly impressed by them. We described the problem to them and they said they'd never heard anything like that, their only suggestion was to put the park brake on every time we park it. I'm considering taking it to a dealer out of town to see if they come up with something better.

Could it still potentially be the battery, even if they tested it? Someone above mentioned that loading the brakes might give a bad battery enough juice to start the car after a few attempts; so if they'd tested it after they got it running, it would show some type of charge? Again, I know nothing about cars...I'm just very frustrated because we purchased this car because we frequently take long trips, but now I'm afraid to take it anywhere because I don't know what it's going to do!

Thanks, all!