OnStar Services

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Fuel
For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax Diesel Supplement. For Vehicles with gasoline engines, please read this. ...

Tow/Haul Mode Light
This light comes on when the Tow/Haul mode has been activated. For more information, see Tow/Haul Mode on page 9‑26. ...

Interior
The Sierra showcases two different interior designs. Work Truck and SLE models are more utility-minded, with large controls and door handles that can be operated while wearing gloves. The SLT offe ...