The doors will lock automatically when all doors are closed, the ignition is on, and the vehicle is shifted out of P (Park).
If a vehicle door is unlocked and then opened and closed, the doors will lock either when your foot is removed from the brake or the vehicle speed becomes faster than 13 km/h (8 mph).
To unlock the doors:
on the power
door lock
switch.Automatic door locking cannot be disabled. Automatic door unlocking can be programmed. See Vehicle Personalization.
Delayed Locking
Lockout Protection#PIC5904: OnStar Account Issues Causing No Connect Concern - (Aug 20, 2013)
Subject:OnStar Account Issues Causing No Connect ConcernModels: 2002-2014 GM Passenger Cars and Trucks The following diagnosis might be helpful if the vehicle exhibits the symptom(s) describedin this PI.Condition/ConcernA customer may report they are not able to connect to OnStar on blue button ...