I'm guessing GM uses the same Nav system on all their cars. Wife has a 13 Buick Lacrosse with Nav. She splits screen left side Nav and right half XM. When the car is first started she gets the Buick logo where we get the Volt logo. Once Buick logo is done she gets a huge black screen saying Navigation Initializing for another 17 to 20 seconds. In the mean time you have no control over the screen. Do your Nav systems act the same way?