My 2009 Toyota Sienna started doing a very strange think. Every so often, I get in put the key in, the dashboard lights up normal but when I turn the ignition the electrical system dies. I found that if I disconnect the battery for a moment, reconnect it, everything returns to normal and the cars starts right up. The battery is good and the starter seems fine. I just lose all electric power every so often. The car does not have a remote key system. Battery terminals are clean.
Sounds like loose connections to me.
If you’re able to remove and replace without using any tools, they’re loose.
Concur w/IM above, I had that same symptom one time, and it was loose battery connections. A clean and tighten fixed it straight away.