GMC Terrain: Keys and Locks / Delayed Locking
This feature delays the actual locking of the doors until five seconds after all doors are closed.
Delayed locking can only be turned on when the Open Door Anti-Lockout feature has been turned off.
When 
is pressed on the power
door lock switch with the door open,
a chime will sound three times
indicating that delayed locking is
active.
The doors will then lock automatically five seconds after all doors are closed. If a door is reopened before five seconds have elapsed, the five-second timer will reset once all the doors are closed again.
Press 
on the door lock switch
again, or press 
on the RKE
transmitter, to override this feature
and lock the doors immediately.
Delayed locking can be programmed. See Vehicle Personalization.
Automatic Door Locks
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)...
Other information:
GMC Terrain 2018-2025 Owners Manual: Prohibited Fuels (Gasoline)
Caution Do not use fuels with any of the following conditions; doing so may damage the vehicle and void its warranty: For vehicles that are not FlexFuel, fuel labeled greater than 15% ethanol by volume, such as mid-level ethanol blends (16–50% ethanol), E85, or FlexFuel...
GMC Terrain 2018-2025 Owners Manual: Approaching and Following a Vehicle
The vehicle ahead indicator is in the instrument cluster. It only displays when a vehicle is detected in your vehicle’s path moving in the same direction. If this symbol is not displaying, ACC will not respond to or brake for vehicles ahead. ACC automatically slows the vehicle down and adjusts vehicle speed to follow a detected vehicle ahead at the selected following gap...