See also:

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 v ...

Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position. - The ignition should turn to LOCK/OFF only when the shift lever is in P (Pa ...

Sunroof
On vehicles with a sunroof, the switches are on the overhead console. The sunroof only operates when the ignition is in ON/RUN/START or ACC/ACCESSORY, or in Retained Accessory Power (RAP). See ...