GMC Terrain Quiz
Instruments and Controls

Malfunction Indicator Lamp (Check Engine Light)

In this manual: Instruments and Controls
Introduction — 1In Brief — 46Keys, Doors and Windows — 37Seats and Restraints — 60Storage — 6Instruments and Controls — 58Lighting — 16Infotainment System — 1Climate Control — 8Driving and Operation — 128Vehicle Care — 75Service and Maintenance — 8Technical Data — 5Customer Information — 18OnStar — 6Connected Services — 4
~2min read

This light is part of the Onboard Diagnostic (OBD) system. If this light comes on while the engine is running, a malfunction has been detected and the vehicle may need service. The light should come on when the ignition is on and the engine is not running, as a check. See Ignition Positions.

This light may also come on when the system has detected a problem with the Diesel Exhaust Fluid (DEF) system. See Diesel Exhaust Fluid.

GMC Terrain. Malfunction Indicator Lamp (Check Engine Light)

Malfunctions are often indicated by the system before any problems become noticeable. Heed the light and seek service immediately, as this may prevent damage.

Flashing Light (Gasoline Engine Only)

If the light is flashing: A malfunction has been detected that may damage the emission control system and increase vehicle emissions. Diagnosis and service may be required.

To prevent damage, reduce vehicle speed and avoid hard acceleration and uphill grades. When towing a trailer, reduce the load being carried as soon as possible.

If the light continues to flash, find a safe place to park. Turn the vehicle off and wait at least 10 seconds before restarting the engine. If the light is still flashing, follow the previous recommendations and see your dealer for service as soon as possible.

Steady On (All Engines)

If the light is on steady: A malfunction has been detected. Diagnosis and service may be required.

Check the following:

  • If fuel was added to the vehicle using a funnel without a cap adapter, be sure it was removed. See "Filling the Tank with a Portable Fuel Container" in Filling the Tank (Gasoline) or Filling the Tank (Diesel). The diagnostic system can determine if the adapter was left installed on the vehicle, allowing fuel to evaporate into the atmosphere. Several driving trips with the adapter removed may turn off the light.
  • Poor fuel quality may cause engine misfire and poor drivability, which may disappear after the engine warms up. If this occurs, change the fuel brand. It may take at least one full tank of proper fuel to turn off the light. See Recommended Fuel (LYX - 1.5L L4 Turbo Engine) or Recommended Fuel (LTG - 2 L L4 Turbo Engine) or Diesel Engine Fuel.

If the light stays on, see your dealer.

Test yourself

A quick GMC Terrain quiz: every answer comes with an explanation and a link to the manual page.