What happened?

Your 12v battery is probably discharged. Use a trickle charger to recharge it and bring it by any auto store for a free battery test to make sure it's still good. If you're still getting free Toyota care services it's probably still under warranty and they'll likely replace your 12v for free.

There are some things you can do to avoid the 12v draining if you aren't driving much. Don't leave the car plugged in the wall if you aren't planning on driving it for longer than a few days, don't keep your key fob inside or too close to the car during storage - those 2 items will keep the car drawing a little power from the 12v as systems are assuming you'll be driving soon or the proximity system is always running with the fob inside. You'd think that Toyota would figure out a way to keep the 12v maintained with the traction battery without discharging both in such a scenario. Especially if the car is connected to a charger the whole time...

If you find you aren't driving often or going on a longer vacation look at buying a 12v battery maintainer like battery tender, and keep a charged emergency jumper in the trunk if you're leaving the car at airport parking or somewhere you can't plug the battery tender in, and jumper cables in case that doesn't work.

 

You don't need to use the dealer for oil changes. Any reputable mechanic can do it, as well as DIY (if capable.) Follow the link for more information.

Magnuson-Moss Warranty Act (MMWA) | Auto Care

 

As commented already, the 12v battery might have died. But to be clear, did you figure out how to unplug the charging cable from the port? For one thing, the car will not start, that is to go to READY mode, if the charging cable is plugged in for safety reasons. It is strange that you could not unplug the charging cord. I thought PP Plus did not have the charging cord lock. It should be all manual.

For long storage, Toyota recommends not to keep the car plugged in. WIth the charge cord plugged, the car will continue to check the connection and try to manage the charger and the traction battery using the 12v battery. This drains the 12v battery faster. Plugging in the charging cord does not charge the 12 v battery.

If you have a jump starter pack or have another vehicle with a good 12v battery, jumpstarting it should start the car. Then you will likely need to replace the 12v battery. And for this and any other maintenance, you don't have to use a dealer service if you don't want to. Toyota can not void the warranty for not using dealer service.

 

THAT is just simply absolutely positively NOT true.
All you need is evidence that the changes were done.

 

You don't have to use a dealer for oil changes. Toyota cannot and will not void your warranty if you choose to go elsewhere for service. The Magnuson-Moss Act is federal law created to stop this illegal and immoral behavior.

https://en.wikipedia.org/wiki/Magnuson%E2%80%93Moss_Warranty_Act

 

There's a couple of options with a limited use vehicle:

1. Keep it hooked up to a quality smart charger, 3~4 amp rated.
2. Disconnect neg battery lead, especially if you don't have secure parking and an AC outlet.

 

The 12v battery is needed to power the electronics to start the car. It doesn't crank the gasoline engine. The 12v battery gets its charge from the main traction battery at specific times. The electronic system puts a small drain on the 12v battery when the charge cable is plugged in, and less drain when the cable is unplugged. Toyota should have told us about this.

If the battery is recharged, tested, and no good, don't buy the expensive one from the dealer. Buy one from NAPA Autoparts or O'Reilly Auto parts, or any other source that sells East Penn/Deka batteries, group size 140R. About $150. They are the only U.S. maker of this size as far as I've found. Even better is to get an ACDelco absorbed glass mat group LN1 battery by mail order from Rock Auto, about the same price.

 

My 2020 Prime Limited has a charge lock on it. I seem to remember that only the limited (or Advanced for 2017) have that feature. I would also guess that once you add a 12 V source/jump, that you could then click the lock/unlock button by the charge port to remove the charge cable.

 

try holding the drivers window switch all the way down, then all the way up

 

Here is something to try.

 

Leaving the charger plugged in drains the 12 V battery; so, don't do it.

 

This is from 2nd gen Repair Manual, the power window intialization procedure:

 

You would think Toyota would make a button to recharge the 12v from the hybrid battery to jump start itself after all these years..

 

In cars with a traditional starter battery, a physical switch needs to engage to reconnect the traction pack. Teslas monitor the 12V and will engage the traction pack to top it off when needed. If the 12V is too low to flip the switch, then having a method won't help.