See also:

Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum capacity, this message may come on. Push to try the call again or try again after driving a few miles into ...

Special Application Services
Severe Commercial Use Vehicles Only: Lubricate chassis components every 5 000 km/3,000 mi. Have underbody flushing service performed once a year. ...

When to Add Engine Oil
If the oil is below the L mark for the L6 engine or the cross-hatched area at the tip of the dipstick for the V8 engine, you will need to add at least one quart/liter of oil. But you must use the ...