There's a warning that seems to be coming up randomly. I checked in the manual and there's no mention of this signal.

It's a yellow circle around square with an exclamation mark in it. Outside the circle are lines, sorta like a crude sun drawing. Any idea what this means?

It's only come on twice now, and doesn't come back after I restart the car.

 

It sounds like you're describing the transmission problem light...

 

or maybe it may be the abs warning light, not the activation light lol

 

Ya it sounds like transmission or brakes to me