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:
Recommended Fuel
Use regular unleaded gasoline with a posted octane rating of 87 or higher.
If the octane rating is less than 87, an audible knocking noise, commonly
referred to as spark knock, might be heard when d ...
How to Inspect the Engine
Air Cleaner/Filter
To inspect the air cleaner/filter,
remove the filter from the vehicle
and lightly shake the filter to release
loose dust and dirt. If the filter
remains covered with dirt, a new
filter is re ...
Sedan and Wagon Base Model
From the inside, use the door lock
knob on the top of doors. ...