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:
Door Ajar Messages
DRIVER DOOR OPEN
This message displays and a chime sounds if the driver door is not fully closed and the vehicle is shifted out of P (Park). Stop and turn off the vehicle, check the door for obstruct ...
Dolly Towing (All-Wheel&-Drive Vehicles)
All-wheel&-drive vehicles should not be towed with two wheels on the ground.
To properly tow these vehicles, they should be placed on a platform trailer with
all four wheels off of the ground ...
Tire Messages
SERVICE TIRE MONITOR SYSTEM
This message displays if there is a problem with the Tire Pressure Monitor System
(TPMS). See Tire Pressure Monitor Operation on page 10‑54 for more information.
...