The back up guidance lines and warning indicators do not always appear or activate when the car is in reverse associated with the back up camera. they are missing intermittently when backing up. i was backing up and trying to judge distance and clearance in my new car. this assist device being non-functional allowed me to back into bushes, doing no damage, but causing alarm. i returned it to the dealership for repair twice and was informed that it was a common problem that nothing could be done about. this began on purchase 3/31/2018 and continues. i will continue to address it with the dealership, but don't expect any long term fix by them. i will maintain my due diligence to ensure i do not run into another vehicle or person, but improperly functioning safety assistance devices are infective and the manufacturer should be made to ensure their proper operation, since i understand this is a common problem on cadillac and other gm systems.