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 vehicle is equipped with the Tire Pressure Monitoring System.
If a diagnostics check is needed between e-mails, push 
, and an Advisor can run a check.
See also:
Tire Rotation and Required Services Every 12 000 km/7,500 mi
Rotate the tires, if recommended for the vehicle, and perform the following services. See Tire Rotation on page 10‑68.
• Check engine oil level and oil life percentage. If needed, change engi ...
General Towing Information
Only use towing equipment that has been designed for the vehicle.
Contact your dealer or trailering dealer for assistance with preparing the vehicle for towing a trailer.
See the following trailer t ...
Engine Oil Additives/Engine Oil Flushes
Do not add anything to the oil. The recommended oils with the dexos specification
and displaying the dexos certification mark are all that is needed for good performance
and engine protection.
En ...