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:
Control of a Vehicle
Braking, steering, and accelerating are important factors in helping to control
a vehicle while driving. ...
Antilock Brake System (ABS)
This vehicle has the Antilock Brake System (ABS), an advanced electronic braking system that helps prevent a braking skid.
When the engine is started and the vehicle begins to drive away, ABS checks ...
Hydraulic Power Steering
Your vehicle has hydraulic power steering. It may require maintenance. See Power Steering Fluid on page 10‑21.
If power steering assist is lost due to a system malfunction, the vehicle can be s ...