Chuckit

I have a 2004 is300, that's hasn't been driven in 7 months. Tried to start it up and the motor runs. But electronically nothing is working like the dashboard. The speedo, rpm, radio and a lot of other things as well. Also drove the car around and the car is in some type of safe or limp mode, not sure what the issue is. I'm thinking its maybe a rely or something. Need some help thanks