Over time, I have noticed that it is taking longer and longer the start the car after I hit the power button. Now, it takes over 10 seconds to start the engine, one time I saw Hybrid Engine Overheating message flared for a split second and disappeared. Based on preliminary research, it sounds like the 12V battery is dying, what do you all think? Sometimes I can't shift into Drive or Reverse and other times, the part of the dashboard goes blank/dark.
Do you mean from 'Start' button press, to ICE cranking? Mine have always taken something around that time, maybe even a bit longer. It is long enough to back out of the garage and repark outside without ICE ever firing up, if I don't dally.
When I somehow fumble an attempt to push the EV button, or something similar, it will fire up much more quickly. But as I added to my previous post after you quoted it, even when new, the normal delay was always long enough to back out of the garage and repark outside without ICE ever firing up, if I don't dally or fumble. On both my current 2012, and original 2010.
As long as READY comes on quick, it's up to the car when (or whether) it feels like starting the engine. You can drive as soon as you see READY.
Mine does that when the engine coolant temperature is still above a certain temperature following a previous driving cycle. Or above a certain lower temperature when the EV mode is active.
Which is also normal and fine. As I said, once READY comes on, it is totally up to the car when, or whether, it feels like starting the engine. You can start driving as soon as READY lights up. The traction battery really isn't all that big, so once you start driving, the engine is pretty much sure to start before you've gone more than a block or two. It just can't go a lot farther on battery alone.
So you're saying you get a block and a half or two blocks and the car stops on the side of the road and the triangle light comes on?
No, that's not what I meant. I meant from parked position sometimes overnight or for hours, if it starts, it can take over 10 secs or I think up to 2-3 minutes today before starting. Sometimes it does not start at all but if it starts, it doesn't die while I am driving.
You're free to start driving before it "starts". As soon as READY lights up. It's a Prius. If it needs to start later, it will.
Are you having any problems because of the ICE not starting sooner? Is the traction battery level getting too low (2 bars or less)? Is the propulsion system balking when you press the 'go pedal'? Is the climate control not putting out heat when you want it to? Absent something like this, I'm not seeing what the problem of delayed ICE startup would be. When mine is in EV mode with the engine coolant temperature above 68F, the ICE won't start until one of the above items triggers it. Outside of EV mode with the coolant above 103F (maybe an ECO-specific threshold?), it can also stay off until a similar trigger occurs.
I had intermittent problems before ICE like can't shift away from Park to Drive or Reverse, one time, the part of the dashboard went dark/blank. It doesn't happen every time, so it's hard to reproduce reliably.
When the engine is cold, will it start promptly while the transmission is still in Park, if you the depress the accelerator part-way down shortly after the "READY" light comes on? It should. If I don't do that, there's a delay of about 12 seconds before the engine starts. The delay will be longer if the engine is hot. Does you car behave the similarly?