Tundra climate control issue

I had a similar issue with my Tundra. Have you checked the electrical connectors to the HVAC system? Sometimes those can get corroded or loose, causing all sorts of weirdness with the air conditioning and heating.

Where exactly are those connectors located? Are they easy to get to, or do I need to pull apart half the dash?

I'm not sure about the exact location in your specific model year, but they are usually around the control panel itself and the temperature sensor. If you're not comfortable poking around, it might be worth getting it checked out by a workshop.

Thanks for the tip. I took it to my mechanic, and it turned out to be a defective cable/plug connection, just like the error code suggested. They fixed it for 95€ Appreciate the help!