RAV4 auxiliary battery malfunction

That sounds familiar! I've got a RAV4, though not the same year, and I had similar electrical gremlins. The error messages and weak starts are a pain. Have you checked the connections to the auxiliary battery? Mine were corroded and causing havoc. Worth a look before more complex stuff.

Can you tell me more about the issues you had? Were the symptoms the same, and did you see anything else? Did the error memory have any codes that might help?

Yes, the symptoms were almost the same – error message, sluggish starts, and the electrics felt off. I didn't note the error codes, I just wanted it fixed. It was a faulty connection and a partially drained auxiliary battery. If cleaning the connections doesn't solve it, get the battery tested or visit a workshop.

I'm going to the workshop. The battery wasn't charging. The repair was 290€. Thanks for the help.