GMC Terrain: Warning Lights, Gauges, and Indicators / Security Light
The security light should come on briefly as the engine is started. If it does not come on, have the vehicle serviced by your dealer. If the system is working normally, the indicator light turns off.
If the light stays on and the engine does not start, there could be a problem with the theft-deterrent system. See Immobilizer Operation.
Diesel Exhaust Fluid (DEF) Warning Light
This light, a Driver Information
Center (DIC) Message, and a chime
come on when there is an issue with
the DEF.
If the DEF issue has not been
corrected, the light will continue to
flash...
High-Beam On Light, Front Fog Lamp Light and Lamps On Reminder
High-Beam On Light
This light comes on when the
high-beam headlamps are in use.
See Headlamp High/Low-Beam
Changer.
IntelliBeam Light
This light comes on when the
IntelliBeam system, if equipped, is
enabled...
Other information:
GMC Terrain 2018-2026 Owners Manual: Emissions Inspection and Maintenance Programs
If the vehicle requires an Emissions Inspection/Maintenance test, the test equipment will likely connect to the vehicle's Data Link Connector (DLC). The DLC is under the instrument panel to the left of the steering wheel. Connecting devices that are not used to perform an Emissions Inspection/Maintenance test or to service the vehicle may affect vehicle operation...
GMC Terrain 2018-2026 Owners Manual: Diesel Exhaust Fluid
Warning Avoid getting Diesel Exhaust Fluid (DEF) on your skin or in your eyes as it could cause irritation. For more safety, handling, and storage information, see the Diesel Exhaust Fluid container label. Diesel Exhaust Fluid (DEF) is used with diesel engines to reduce the amount of regulated emissions produced...
Copyright © 2026 www.gmcterrain2.com