See also:

Additives
To provide cleaner air, all gasolines in the United States are now required to contain additives that help prevent engine and fuel system deposits from forming, allowing the emission control sys ...

Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if the v ...

Owner Checks and Services
At Each Fuel Stop Check the engine oil level. See Engine Oil . Once a Month Check the tire inflation pressures. See Tire Pressure . Inspect the tires for wear. See Tire Inspection . Che ...