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 
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Advisor can run a check.
See also:
SERVICE ALL WHEEL DRIVE
This message displays if a problem
occurs with the All-Wheel Drive
(AWD) system. The vehicle will run
in 2WD. This could be caused by:
- An electronics problem
- An AWD system oil overheat
- ...
Fuel
Use of the recommended fuel is an important part of the proper maintenance
of this vehicle. To help keep the engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline a ...
Trans (Transmission) Temp (Temperature) (CTS-V Only)
This display shows the transmission
fluid temperature in either degrees
Celsius (°C) or degrees
Fahrenheit (°F). ...