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:
Footnotes — Maintenance Schedule Additional Required Services — Normal
a) Check all fuel and vapor lines and hoses for proper hook-up, routing, and condition. Check that the purge valve, if the vehicle has one, works properly. Replace as needed.
b) Or every four years, ...
Parental Control
The RSE system may have a Parental Control feature, depending on the radio. To enable Parental Control, press and hold the radio power button for more than two seconds to stop all system features such ...
Flash-to-Pass
This feature is used to signal to the vehicle ahead that you want to pass.
If the headlamps are off or in the low-beam position, pull the turn signal lever toward you to momentarily switch to high be ...