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 InformationCalifornia Fuel Requirements
If the vehicle is certified to meet California Emissions Standards, it is designed
to operate on fuels that meet California specifications. See the underhood emission
control label. If this fuel is not available in states adopting California Emissions
Standards, the vehicle will operate satisf ...
Automatic Door Locks
If equipped, the vehicle is programmed so that when the doors are closed, the
ignition is on, and the shift lever is moved out of P (Park) for automatic transmissions,
or the vehicle speed is above 13 km/h (8 mph) for manual transmissions, the doors
and the liftgate will lock.
To unlock the d ...
Checking Coolant
The vehicle must be on a level surface when checking the coolant level.
It is normal to see coolant moving in the upper coolant hose return line when
the engine is running.
Check to see if coolant is visible in the coolant surge tank. If the coolant
inside the coolant surge tank is boiling, do ...