I'm still seeing this issue, but there are some patterns: This started when temps were under 40F at night pretty consistently No heat, no front defroster, etc. are on It typically happens the first time I drive the car for the day (or couple of days) Battery is typically fully charged at least a few hours (4-5) before, sometimes the day before It falls out of EV within the first mile or driving On the highway, twice, I would turn on cruise control... EV would go off. Turn off cruise... EV kicks right back on. I was able to reproduce this 3-4 times in a row. Once the engine warms up (~4-5min), EV mode kicks back on Subsequent driving it stays in EV mode We'll see what happens once the weather gets even colder during the day. I'm guessing maybe Toyota tweaked something for 2021+ so that the engine kicks on even more easily when the traction battery is "cold". Its definitely annoying, and I'll be even more annoyed if it does this even more often when the temps are colder, but we'll see.
Prepare to be more annoyed unless you can change driving patterns enough at those times when the engine turns on, to help the car keep the engine off. The car, more than likely can be coaxed to keep the engine off with a bit of babying, it just takes time and sometimes lots of frustrating time to learn why the engine is turning on when you think it should not have to. It nearly always gets more frustrating to keep the engine from starting unexpectedly as temps approach freezing and drop below.
Yeah, I expected it when it got really cold. I didn’t expect it at 40+F though. I’d also love it if the car communicated why it’s coming out of EV mode. I’m guessing that’s “Toyota proprietary algorithms” and not something I can determine from an ODB scanner or similar? Next vehicle will definitely be a full EV.
