Use of the recommended fuel is an important part of the proper maintenance of this vehicle. When driving in the U.S. and Canada, to help keep the engine clean and maintain optimum vehicle performance, we recommend using TOP TIER Detergent Gasolines.
See www.toptiergas.com for a list of TOP TIER Detergent Gasolines.

Use regular unleaded gasoline meeting ASTM specification D4814 with a posted octane rating of 87 or higher. Do not use gasoline with an octane rating below 87, as it may cause engine damage and will lower fuel economy.
Use of Seasonal Fuels
Use summer and winter fuels in the appropriate season. The fuels industry automatically modifies the fuel for the appropriate season.
If fuel is left in the vehicle tank for long periods of time, driving or starting could be affected. Drive the vehicle until the fuel is at one-half tank or less, then refuel with the current seasonal fuel.
Prohibited Fuels
Gasolines containing oxygenates such as ethers and ethanol, as well as reformulated gasolines, are available in some cities. If these gasolines comply with the previously described specification, then they are acceptable to use.
However, E85 (85% ethanol) and other fuels containing more than 15% ethanol must be used only in FlexFuel vehicles.
Caution
Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic and rubber parts.
That damage would not be covered under the vehicle warranty.
Some gasolines, mainly high octane racing gasolines, can contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT). Do not use gasolines and/or fuel additives with MMT as they can reduce spark plug life and affect emission control system performance. The malfunction indicator lamp may turn on. If this occurs, see your dealer for service.
Driver Assistance Systems
California Fuel RequirementsConnections
The required specific Onstar subscription plan includes the services that follow
to help customers stay connected.
For coverage maps, see www.onstar.com (U.S.) or www.onstar.ca (Canada).
WiFi Connectivity (If Equipped)
The vehicle has a WiFi hotspot that provides a high-speed, wireless Internet ...
Radio with Touchscreen
VOL
(Volume)
Press to decrease or increase the volume.
(Power)
Press and hold to turn the power on or off.
(Home Page)
Press to go to the Home Page. See Home Page (Radio with Touchscreen) on
page 7-5.
...
If the Off Indicator Is Lit for an Adult-Sized Occupant
If a person of adult size is sitting in the front outboard passenger seat, but
the off indicator is lit, it could be because that person is not sitting properly
in the seat or that the child restraint locking feature is engaged.
Use the following steps to allow the system to detect that per ...