See also:

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 ...

Checking Engine Oil
It is a good idea to check the engine oil level at each fuel fill. In order to get an accurate reading, the vehicle must be on level ground. The engine oil dipstick handle is a yellow loop. See Engi ...

When to Check
Check the tires once a month or more. Do not forget the spare tire, if the vehicle has one. SeeFull-Size Spare Tire on page 10‑91 for additional information. ...