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:
Automatic Dimming Rearview Mirror
The vehicle may have an automatic dimming inside rearview mirror.
Automatic dimming reduces the glare from the headlamps of the vehicle behind you. The dimming feature comes on and the indicator ligh ...
Delayed Entry Lighting
Delayed entry lighting illuminates the interior for a period of time after all the doors have been closed.
The ignition must be off for delayed entry lighting to work. Immediately after all the doors ...
Tire Size
The following is an example of a typical passenger vehicle tire size.
(A) Passenger (P&-Metric) Tire: The United States version of a metric tire sizing
system. The letter P as the first chara ...