OnStar Vehicle Diagnostics can perform a vehicle check every month. It will check
the engine, transmission, antilock brakes, and other major vehicle systems. It also
checks the tire pressures, if the vehicle is equipped with the Tire Pressure Monitoring
System. If an On-Demand Diagnostics check is needed, press
, and an Advisor can run a check.
Connections
OnStar Additional InformationUniform Tire Quality Grading
The following information relates to the system developed by the United States
National Highway Traffic Safety Administration (NHTSA), which grades tires by treadwear,
traction, and temperature performance. This applies only to vehicles sold in the
United States. The grades are molded on the s ...
Parking
If the vehicle has a manual transmission, before getting out of the vehicle,
move the shift lever into R (Reverse) if parking on a downhill slope. On a level
surface or an uphill slope, use 1 (First) gear.
Firmly apply the parking brake. Turn the wheels toward the curb for a downhill
slope, o ...
Shifting out of Park
This vehicle is equipped with a shift lock control. The shift lock control is
designed to:
Prevent ignition key removal unless the shift lever is in P (Park) with
the shift lever button fully released.
Prevent movement of the shift lever out of P (Park) unless the ignition
is in ON/RUN ...